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Entry  26 Jan 2022, Frederik Wauters, Forum, .gz files 
I adapted our analyzer to compile against the manalyzer included in the midas repo.

All our data files are .mid.gz, which now fail to process :(

frederik@frederik-ThinkPad-T550:~/new_daq/build/analyzer$ ./analyzer -e100 -s100 ../../run_backup_11783.mid.gz 
...
...n
Registered modules: 1
file[0]: ../../run_backup_11783.mid.gz
Setting up the analysis!
TMReadEvent: error: short read 0 instead of -1193512213

Which is in the TMEvent* TMReadEvent(TMReaderInterface* reader) class in the midasio.cxx file

Reading the unzipped files works. But we have always processed our .gz files directly, for the unzipping we would need ~2x disk space.

Am I doing something wrong? I see that there is some activity on lz4 in the midasio repo, is gunzip next?
    Reply  26 Jan 2022, Konstantin Olchanski, Forum, .gz files 
> I adapted our analyzer to compile against the manalyzer included in the midas repo.
> TMReadEvent: error: short read 0 instead of -1193512213

I think this problem is fixed in the latest version of midasio and manalyzer, but this update
was not pulled into midas yet. (Canada is in the middle of a covid wave since December).

What happens is you do not have the gzip library installed on your computer and
your analyzer is built without support for gzip.

The fix is done the hard way, the gzip library is no longer optional, but required.

You do not say what linux you use, so I cannot give exact instructions, but for:
ubuntu: apt -y install libz-dev
centos7: installed by default
centos8: installed by default
debian11/raspbian: same as ubuntu

K.O.
       Reply  31 Jan 2022, Frederik Wauters, Forum, .gz files 
> > I adapted our analyzer to compile against the manalyzer included in the midas repo.
> > TMReadEvent: error: short read 0 instead of -1193512213
> 
> I think this problem is fixed in the latest version of midasio and manalyzer, but this update
> was not pulled into midas yet. (Canada is in the middle of a covid wave since December).
> 
> What happens is you do not have the gzip library installed on your computer and
> your analyzer is built without support for gzip.
> 
> The fix is done the hard way, the gzip library is no longer optional, but required.
> 
> You do not say what linux you use, so I cannot give exact instructions, but for:
> ubuntu: apt -y install libz-dev
> centos7: installed by default
> centos8: installed by default
> debian11/raspbian: same as ubuntu
> 
> K.O.

My libz under ubuntu

-- Found ZLIB: /usr/lib/x86_64-linux-gnu/libz.so (found version "1.2.11") 
-- MIDAS: Found ZLIB version 1.2.11

I got both the manalyzer example and mine going with
* the latest midas dev
* + the latest manalyzer (cf6c233)
* + almost latest midasio (568a617, otherwise I get an linking error 

./libmidas.a(midasio.cxx.o): In function `Lz4Error(int)':
midasio.cxx:(.text+0x359): undefined reference to `MLZ4F_getErrorName(unsigned long)'

So this works, I will assume that in the near future this all will come together in the standard midas release.

thanks  
Entry  29 Jan 2022, Isaac Labrie Boulay, Forum, MIDAS and GRIF-16 digitizer (Standalone Mode). 
Hi all,

I was sent a version of the frontend for the TIGRESS Detector lab setup so that 
I can test detectors using a GRIF-16 digitizer in standalone mode.

I followed the GRIF-16 wiki (https://grsi.wiki.triumf.ca/wiki/GRIF-16#One-
level_operation) to setup the GRIF-16 through the webpage. The digitized data is 
supposed to come into my UDP port 8800 but it is never retrieved in the 
frontend.

Here's the readout scheme:
// readout sequence ...
// poll_event() true (if still have data in buffer or testmsg() true)
// -> read_trigger_event() -> read_grifc_event() - re-buffers into midas events
//                         -> grifc_eventread()  - returns single grif fragment
//                         -> grifc_dataread()   - returns single net-pkt 


Here's poll_event():
INT poll_event(INT source, INT count, BOOL test)
{
   int i, have_data=0;

   for(i=0; i<count; i++){
      if( data_available ){ break; }
      have_data = ( testmsg(data_socket, 0) > 0 );
      if( have_data && !test ){ break; }
   }
   return( (have_data || data_available) && !test );
}

This being said, testmsg() always returns empty and "data_available" is only set 
to TRUE when there's leftover data after a GRIF-C reading (I'm obviously not 
using a GRIF-C).

I know that when GRIF-16 is in standalone mode, MIDAS does not change GRIF-16s 
settings based on the ODB, it has to be done through the GRIF-16 webpage. Is the 
user frontend code even responsible for the GRIF-16 data readout in standalone 
mode? If not, could it just be that my UDP offloader is incorrectly setup?

Here are its current settings:

SETTINGS/UDP
- Offloader: ON
- Dst IP: my IP
- Dst Port: 8800 (DATA_PORT)

SETTINGS/MIDAS
- Use MIDAS: OFF
- MIDAS Hostname: my hostname
- MIDAS IP: same as Dst IP from UDP settings
- Dst Port: 8080 (I'm assuming that this is the mhttpd port)

Again, the frontend runs but I get 0 events. What might I be missing?

Thanks for helping me out!

Isaac
Entry  22 Oct 2021, Francesco Renga, Forum, mhttpd error 
Dear all,
      I am trying to make the MIDAS web server for my DAQ project accessible from other machines. In the ODB, I activated the necessary flags:

[local:CYGNUS_RD:S]/WebServer>ls
Enable localhost port           y
localhost port                  8080
localhost port passwords        n
Enable insecure port            y
insecure port                   8081
insecure port passwords         y
insecure port host list         y
Enable https port               y
https port                      8443
https port passwords            y
https port host list            n
Host list
                                localhost
Enable IPv6                     y
Proxy                           
mime.types

Following the instructions on the Wiki I enabled the SSL support. When running mhttpd, I get these messages:

Mongoose web server will use HTTP Digest authentication with realm "CYGNUS_RD" and password file "/home/cygno/DAQ/online/htpasswd.txt"
Mongoose web server will use the hostlist, connections will be accepted only from: localhost
Mongoose web server listening on http address "localhost:8080", passwords OFF, hostlist OFF
Mongoose web server listening on http address "[::1]:8080", passwords OFF, hostlist OFF
Mongoose web server listening on http address "8081", passwords enabled, hostlist enabled
[mhttpd,ERROR] [mhttpd.cxx:19166:mongoose_listen,ERROR] Cannot mg_bind address "[::0]:8081"
Mongoose web server will use https certificate file "/home/cygno/DAQ/online/ssl_cert.pem"
Mongoose web server listening on https address "8443", passwords enabled, hostlist OFF
[mhttpd,ERROR] [mhttpd.cxx:19166:mongoose_listen,ERROR] Cannot mg_bind address "[::0]:8443"

and the server is not accessible from other machines. Any suggestion to solve or better investigate this problem?

Thank you very much,
         Francesco
    Reply  22 Oct 2021, Stefan Ritt, Forum, mhttpd error 
> Enable IPv6                     y

Probably the IPv6 problem, see here elog:2269

I asked to turn off IPv6 by default, or at least mention this in the documentation,
but unfortunately nothing happened.

Stefan
       Reply  25 Oct 2021, Francesco Renga, Forum, mhttpd error 
It worked, thank you very much!

Francesco

> > Enable IPv6                     y
> 
> Probably the IPv6 problem, see here elog:2269
> 
> I asked to turn off IPv6 by default, or at least mention this in the documentation,
> but unfortunately nothing happened.
> 
> Stefan
       Reply  26 Jan 2022, Konstantin Olchanski, Forum, mhttpd error 
> > Enable IPv6                     y
> 
> Probably the IPv6 problem, see here elog:2269
> 
> I asked to turn off IPv6 by default, or at least mention this in the documentation,
> but unfortunately nothing happened.

But IPv4 and IPv6 code is completely separate, if IPv6 bind fails, IPv4 should still 
work.

This is all very strange.

It does not help that the OP does not say in which way things do not work,
"the server is not accessible from other machines" is not an error message
reported by any browser, and we do not know what URL he is using
to access mhttpd - http: or https:

Also he is enabling the "insecure" port 8081, I am pretty sure the documentation
is pretty clear, either use the secure https port or the insecure port,
but not both at the same time.

In any case, I see current version of mongoose have removed support
for password files, so all this stuff will likely become reworked
and at the end mhttpd will only listen to localhost ports. To make it "accessible
to other machines", one will have to use the apache https proxy. (or mtpcproxy from 
midas).

K.O.
Entry  29 Oct 2021, Kushal Kapoor, Bug Report, Unknown Error 319 from client Screenshot_2021-10-26_114015.png
I’m trying to run MIDAS using a frontend code/client named “fetiglab”. Run stops 
after 2/3sec with an error saying “Unknown error 319 from client “fetiglab” on 
localhost.

Frontend code compiled without any errors and MIDAS reads the frontend 
successfully, this only comes when I start the new run on MIDAS, here are a few 
more details from the terminal-

11:46:32 [fetiglab,ERROR] [odb.cxx:11268:db_get_record,ERROR] struct size 
mismatch for "/" (expected size: 1, size in ODB: 41920)

11:46:32 [Logger,INFO] Deleting previous file 
"/home/rcmp/online3/run00621_000.root"

11:46:32 [ODBEdit,ERROR] [midas.cxx:5073:cm_transition,ERROR] transition START 
aborted: client "fetiglab" returned status 319

11:46:32 [ODBEdit,ERROR] [midas.cxx:5246:cm_transition,ERROR] Could not start a 
run: cm_transition() status 319, message 'Unknown error 319 from client 
'fetiglab' on host "localhost"'

TR_STARTABORT transition: cleanup after failure to start a run

&#8204;

I’ve also enclosed a screenshot for the same, any suggestions would be highly 
appreciated. thanks
    Reply  26 Jan 2022, Konstantin Olchanski, Bug Report, Unknown Error 319 from client 
> I’m trying to run MIDAS using a frontend code/client named “fetiglab”. Run stops 
> after 2/3sec with an error saying “Unknown error 319 from client “fetiglab” on 
> localhost.

actually run never starts.

> 11:46:32 [fetiglab,ERROR] [odb.cxx:11268:db_get_record,ERROR] struct size 
> mismatch for "/" (expected size: 1, size in ODB: 41920)

this is the error that causes run start to fail. for reasons unknown
your frontend is trying to do a db_get_record() from "/" (ODB root top directory).

if this is an mfe.c frontend, I do not think I have ever seen it do something
like this.

so, a puzzle.

K.O.
Entry  01 Dec 2021, Lars Martin, Bug Report, Off-by-one in sequencer documentation 
The documentation for the sequencer loop says:

<quote>
LOOP [name ,] n ... ENDLOOP	To execute a loop n times. For infinite loops, "infinite" 
can be specified as n. Optionally, the loop variable running from 0...(n-1) can be accessed 
inside the loop via $name.
</quote>

In fact the loop variable runs from 1...n, as can be seen by running this exciting 
sequencer code:

1 COMMENT "Figuring out MSL"
2 
3 LOOP n,4
4   MESSAGE $n,1
5 ENDLOOP
    Reply  02 Dec 2021, Stefan Ritt, Bug Report, Off-by-one in sequencer documentation 
> The documentation for the sequencer loop says:
> 
> <quote>
> LOOP [name ,] n ... ENDLOOP	To execute a loop n times. For infinite loops, "infinite" 
> can be specified as n. Optionally, the loop variable running from 0...(n-1) can be accessed 
> inside the loop via $name.
> </quote>
> 
> In fact the loop variable runs from 1...n, as can be seen by running this exciting 
> sequencer code:
> 
> 1 COMMENT "Figuring out MSL"
> 2 
> 3 LOOP n,4
> 4   MESSAGE $n,1
> 5 ENDLOOP

Indeed you're right. The loop variable runs from 1...n. I fixed that in the documentation.

Stefan
       Reply  26 Jan 2022, Konstantin Olchanski, Bug Report, Off-by-one in sequencer documentation 
> > 3 LOOP n,4
> > 4   MESSAGE $n,1
> > 5 ENDLOOP
> 
> Indeed you're right. The loop variable runs from 1...n. I fixed that in the documentation.

Shades/ghosts of FORTRAN. c/c++/perl/python loops loop from 0 to n-1.

K.O.
          Reply  26 Jan 2022, Stefan Ritt, Bug Report, Off-by-one in sequencer documentation 
> Shades/ghosts of FORTRAN. c/c++/perl/python loops loop from 0 to n-1.

   for (i=1 ; i<=10 ; i++);     ;-)
             Reply  26 Jan 2022, Konstantin Olchanski, Bug Report, Off-by-one in sequencer documentation 
> > Shades/ghosts of FORTRAN. c/c++/perl/python loops loop from 0 to n-1.
> 
>    for (i=1 ; i<=10 ; i++);     ;-)

Similar code made big news just recently: (scroll down to the example main() program)

https://blog.qualys.com/vulnerabilities-threat-research/2022/01/25/pwnkit-local-privilege-escalation-
vulnerability-discovered-in-polkits-pkexec-cve-2021-4034

I forget if the FORTRAN rules were "loop once" or "never loop" or if it was different
between Fortran-4, fortran-77, DEC extensions and IBM extension, or if it was a compiler switch.

We should check that we do something reasonable with such loops to zero:

LOOP n,0
   MESSAGE $n,1
ENDLOOP

P.S. Yup. "man g77" option "-fonetrip".

K.O.
Entry  09 Nov 2021, Francesco Renga, Forum, Issue in data writing speed 
Dear all,
       I've a frontend writing a quite big bunch of data into a MIDAS bank (16bit output from a 4MP photo camera). 
I'm experiencing a writing speed problem that I don't understand. When the photo camera is triggered at a low rate (< 2 Hz) 
writing into the bank takes a very short time for each event (indeed, what I measure is the time to write and go back 
into the polling function). If I increase the rate to 4 Hz, I see that writing the first two events takes a sort time, 
but the third event takes a very long time (hundreds of ms), then again the fourth and fifth events are very fast, and 
the sixth is very slow. If I further increase the rate, every other event is very slow. The problem is not in the readout 
of the camera, because if I just remove the bank writing and keep the camera readout, the problem disappears. Can you 
explain this behavior? Is there any way to improve it?

Below you can also find the code I use to copy the data from the camera buffer into the bank. If you have any suggestion 
to improve it, it would be really appreciated.

Thank you very much,
          Francesco



  const char* pSrc = (const char*)bufframe.buf;

  for(int y = 0; y < bufframe.height; y++ ){

    //Copy one row
    const unsigned short* pDst = (const unsigned short*)pSrc;

    //go through the row
    for(int x = 0; x < bufframe.width; x++ ){

      WORD tmpData = *pDst++; 

      *pdata++ = tmpData;

    }

    pSrc += bufframe.rowbytes;

  }
 
    Reply  10 Nov 2021, Stefan Ritt, Forum, Issue in data writing speed 
Midas uses various buffers (in the frontend, at the server side before the SYSTEM buffer, the SYSTEM buffer itself, on the 
logger before writing to disk. All these buffers are in RAM and have fast access, so you can fill them pretty quickly. When
they are full, the logger writes to disk, which is slower. So I believe at 2 Hz your disk can keep up with your writing 
speed, but at 4 Hz (2x8MBx4=32 MB/sec) your disk starts slowing down the writing process. Now 32MB/s is pretty slow for
a disk, so I presume you have turned compression on which takes quite some time.

To verify this, disable logging. The disable compression and keep logging. Then report back here again.

> Dear all,
>        I've a frontend writing a quite big bunch of data into a MIDAS bank (16bit output from a 4MP photo camera). 
> I'm experiencing a writing speed problem that I don't understand. When the photo camera is triggered at a low rate (< 2 Hz) 
> writing into the bank takes a very short time for each event (indeed, what I measure is the time to write and go back 
> into the polling function). If I increase the rate to 4 Hz, I see that writing the first two events takes a sort time, 
> but the third event takes a very long time (hundreds of ms), then again the fourth and fifth events are very fast, and 
> the sixth is very slow. If I further increase the rate, every other event is very slow. The problem is not in the readout 
> of the camera, because if I just remove the bank writing and keep the camera readout, the problem disappears. Can you 
> explain this behavior? Is there any way to improve it?
> 
> Below you can also find the code I use to copy the data from the camera buffer into the bank. If you have any suggestion 
> to improve it, it would be really appreciated.
> 
> Thank you very much,
>           Francesco
> 
> 
> 
>   const char* pSrc = (const char*)bufframe.buf;
> 
>   for(int y = 0; y < bufframe.height; y++ ){
> 
>     //Copy one row
>     const unsigned short* pDst = (const unsigned short*)pSrc;
> 
>     //go through the row
>     for(int x = 0; x < bufframe.width; x++ ){
> 
>       WORD tmpData = *pDst++; 
> 
>       *pdata++ = tmpData;
> 
>     }
> 
>     pSrc += bufframe.rowbytes;
> 
>   }
>  
    Reply  26 Jan 2022, Konstantin Olchanski, Forum, Issue in data writing speed 
Francesco, when you say "writing an event is slow", do you mean it in the frontend
or in the output data file?

Stefan is quite right about the data file, it can take seconds between generating
an event in the frontend and seeing it written to the data file. (if compression
buffers are too big, an event can sit there forever, until pushed out by next events
or by run stop).

But maybe you see this on the frontend side.

What you are looking at is "real time" performance of the frontend and of the linux kernel.

The mfe.c frontend has many problems with real time performance, it can stall and take a long
time between calls to read_event(), for many reasons.

There are ways around that, but it is simpler to switch to the tmfe c++ frontend
that was designed for good real time performance.

In the tmfe frontend, if you use the polled equipment and enable the poll thread,
your frontend will be limited only by the linux kernel real time performance (i.e.
on a single-core CPU, other programs will delay execution of your frontend
and you will see it as long delays (usec, millisec) between calls to your read_event().

Next limit to real time performance (common to mfe.c and tmfe frontends) is the writing
of event data to the midas shared event buffer. One has to lock the shared memory semaphore
and this has to wait until other users of the event buffer finish their reading
or writing and unlock it. Arbitrary amount of time (usec, millisec, sec) can pass.
(there is also problems with "fairness" of the linux semaphores, a different story, again).

Making things more interesting, midas event buffers implement a write cache (default size 100 kbytes),
events smaller than the cache are quickly accumulated (no need to lock the shared memory semaphore),
them flushed to shared memory when cache is full. This is done to reduce the number
of shared memory semaphore locks per event, in the case of very high rate of very small events.

Solution to all this is to use 2 threads: read the data from hardware in one thread and write the data to midas
in a different thread. Between the threads would be an event fifo (circular buffer in mfe.c,
std::deque<EVENT> in tmfe c++ frontends).

For remote connected frontends, things are a bit different. Event data is written directly
into the TCP socket and as long as socket buffers are big enough, there is no real-time delays,
unless SYSTEM buffer is very congested and mserver does not read the TCP socket quickly enough.
So depending on event size, data rate and tcp socket buffer size, the extra 2nd thread
may not be necessary and poll thread real time performance may be good enough.

I hope this clarifies the situation somewhat.

K.O.

> Dear all,
>        I've a frontend writing a quite big bunch of data into a MIDAS bank (16bit output from a 4MP photo camera). 
> I'm experiencing a writing speed problem that I don't understand. When the photo camera is triggered at a low rate (< 2 Hz) 
> writing into the bank takes a very short time for each event (indeed, what I measure is the time to write and go back 
> into the polling function). If I increase the rate to 4 Hz, I see that writing the first two events takes a sort time, 
> but the third event takes a very long time (hundreds of ms), then again the fourth and fifth events are very fast, and 
> the sixth is very slow. If I further increase the rate, every other event is very slow. The problem is not in the readout 
> of the camera, because if I just remove the bank writing and keep the camera readout, the problem disappears. Can you 
> explain this behavior? Is there any way to improve it?
> 
> Below you can also find the code I use to copy the data from the camera buffer into the bank. If you have any suggestion 
> to improve it, it would be really appreciated.
> 
> Thank you very much,
>           Francesco
> 
> 
> 
>   const char* pSrc = (const char*)bufframe.buf;
> 
>   for(int y = 0; y < bufframe.height; y++ ){
> 
>     //Copy one row
>     const unsigned short* pDst = (const unsigned short*)pSrc;
> 
>     //go through the row
>     for(int x = 0; x < bufframe.width; x++ ){
> 
>       WORD tmpData = *pDst++; 
> 
>       *pdata++ = tmpData;
> 
>     }
> 
>     pSrc += bufframe.rowbytes;
> 
>   }
>  
       Reply  26 Jan 2022, Konstantin Olchanski, Forum, Issue in data writing speed 
> Francesco, when you say "writing an event is slow", do you mean it in the frontend
> or in the output data file?

Another explanation just occurred to me. We do not know your event size and we do not
know the size of your SYSTEM buffer. But if you have an unlucky combination,
this can happen:

Consider event size is 6 Mbytes, buffer size is 8 Mbytes, enough space for only 1 event.

First event is written quickly (buffer is empty).
Second event will be delayed, there is not enough free space in the buffer, we have
to wait for mlogger to finish reading the first event.

Same thing happens if event size is 3 Mbytes, the first 2 events will write quickly,
writing the 3rd event will be delayed until mlogger does it's thing.

The mlogger reads the SYSTEM buffer "fast" and "quickly", but it can be delayed
for a number of reasons, i.e. handling a history event, a delay writing to disk,
a delay writing to network connected storage, etc.

In general, it is best to size the SYSTEM buffer to hold about 1 second worth
of data (of average size, average rate). If your event size is 4 Mbytes, and you
record them at 10/sec, SYSTEM buffer should be at least 40 Mbytes big. (this is
set in ODB /Experiment/Buffer Sizes). (MIDAS event buffer size is limited to 2 GBytes).

K.O.
Entry  09 Nov 2021, Hunter Lowe, Forum, MityCAMAC Login  
Hello all,

I've recently acquired a MityCAMAC system that was built at TRIUMF and I'm 
having issues accessing it over ethernet.

The system: Ubuntu VM inside Windows 10 machine.

I've tried reconfiguring the network settings for the VM but nmap and arp/ip 
commands have yielded me no results in finding the crate controller. 

I was getting help from Pierre Amaudruz but I think he is now busy for some 
time. I have the mac address of the crate controller and its name. The 
controller seems to initialize fine inside of the CAMAC crate. The windows side 
of the workstation also tells me that an unknown network is in fact connected.

I suspect I either need to do something with an ssh key (which I thought we 
accomplished but maybe not), or perhaps the domain name in the controller needs 
to be changed. 

If anybody has experience working with MityARM I would appreciate any advice I 
could get.

Best,
Hunter Lowe
UNBC Graduate Physics
    Reply  11 Nov 2021, Thomas Lindner, Forum, MityCAMAC Login  
Hi Hunter 

This sounds like a Triumf specific problem; 
not a MIDAS problem.  Please email me directly 
and we can try to solve this problem.

Thomas Lindner
TRIUMF DAQ


 Hello all,
> 
> I've recently acquired a MityCAMAC system 
that was built at TRIUMF and I'm 
> having issues accessing it over ethernet.
> 
> The system: Ubuntu VM inside Windows 10 
machine.
> 
> I've tried reconfiguring the network 
settings for the VM but nmap and arp/ip 
> commands have yielded me no results in 
finding the crate controller. 
> 
> I was getting help from Pierre Amaudruz but 
I think he is now busy for some 
> time. I have the mac address of the crate 
controller and its name. The 
> controller seems to initialize fine inside 
of the CAMAC crate. The windows side 
> of the workstation also tells me that an 
unknown network is in fact connected.
> 
> I suspect I either need to do something with 
an ssh key (which I thought we 
> accomplished but maybe not), or perhaps the 
domain name in the controller needs 
> to be changed. 
> 
> If anybody has experience working with 
MityARM I would appreciate any advice I 
> could get.
> 
> Best,
> Hunter Lowe
> UNBC Graduate Physics
       Reply  26 Jan 2022, Konstantin Olchanski, Info, MityCAMAC Login  
For those curious about CAMAC controllers, this one was built around 2014 to 
replace the aging CAMAC A1/A2 controllers (parallel and serial) in the TRIUMF 
cyclotron controls system (around 50 CAMAC crates). It implements the main
and the auxiliary controller mode (single width and double width modules).

The design predates Altera Cyclone-5 SoC and has separate
ARM processor (TI 335x) and Cyclone-4 FPGA connected by GPMC bus.

ARM processor boots Linux kernel and CentOS-7 userland from an SD card,
FPGA boots from it's own EPCS flash.

User program running on the ARM processor (i.e. a MIDAS frontend)
initiates CAMAC operations, FPGA executes them. Quite simple.

K.O.
Entry  16 Dec 2021, Zaher Salman, Forum, Device driver for modbus 
Dear all, does anyone have an example of for a device driver using modbus or modbus tcp to communicate with a device and willing to share it? Thanks.
    Reply  26 Jan 2022, Konstantin Olchanski, Forum, Device driver for modbus 
> Dear all, does anyone have an example of for a device driver using modbus or modbus tcp to communicate with a device and willing to share it? Thanks.

I have not seen any modbus devices recently, so all my code and examples are quite old.

Basic modbus/tcp communication driver is in the midas repo:

daq00:midas$ find . | grep -i modbus
./drivers/divers/ModbusTcp.cxx
./drivers/divers/ModbusTcp.h
daq00:midas$ 

This driver worked for communication to a modbus PLC (T2K/ND280/TPC experiment in Japan).

An example program to use this driver and test modbus communication is here:
https://bitbucket.org/expalpha/agdaq/src/master/src/modbus.cxx

Because at the end, we do not have any modbus devices in any recent experiment,
I do not have any example of using this driver in the midas frontend. Sorry.

K.O.
Entry  19 Nov 2021, Jacob Thorne, Forum, Sequencer error with ODB Inc 
Hi,

I am having problems with the midas sequencer, here is my code:

1  COMMENT "Example to move a Standa stage"
2  RUNDESCRIPTION "Example movement sequence - each run is one position of a single stage
3  
4  PARAM numRuns
5  PARAM sequenceNumber
6  PARAM RunNum
7  
8  PARAM positionT2
9  PARAM deltapositionT2
10 
11 ODBSet "/Runinfo/Run number", $RunNum
12 ODBSet "/Runinfo/Sequence number", $sequenceNumber
13 
14 ODBSet "/Equipment/Neutron Detector/Settings/Detector/Type of Measurement", 2
15 ODBSet "/Equipment/Neutron Detector/Settings/Detector/Number of Time Bins", 10
16 ODBSet "/Equipment/Neutron Detector/Settings/Detector/Number of Sweeps", 1
17 ODBSet "/Equipment/Neutron Detector/Settings/Detector/Dwell Time", 100000
18 
19 ODBSet "/Equipment/MTSC/Settings/Devices/Stage 2 Translation/Device Driver/Set Position", $positionT2
20 
21 LOOP $numRuns
22  WAIT ODBvalue, "/Equipment/MTSC/Settings/Devices/Stage 2 Translation/Ready", ==, 1
23  TRANSITION START
24  WAIT ODBvalue, "/Equipment/Neutron Detector/Statistics/Events sent", >=, 1
25  WAIT ODBvalue, "/Runinfo/State", ==, 1
26  WAIT ODBvalue, "/Runinfo/Transition in progress", ==, 0
27  TRANSITION STOP
28  ODBInc "/Equipment/MTSC/Settings/Devices/Stage 2 Translation/Device Driver/Set Position", $deltapositionT2
29 
30 ENDLOOP
31 
32 ODBSet "/Runinfo/Sequence number", 0

The issue comes with line 28, the ODBInc does not work, regardless of what number I put I get the following error:

[Sequencer,ERROR] [odb.cxx:7046:db_set_data_index1,ERROR] "/Equipment/MTSC/Settings/Devices/Stage 2 Translation/Device Driver/Set Position" invalid element data size 32, expected 4

I don't see why this should happen, the format is correct and the number that I input is an int.

Sorry if this is a basic question.

Jacob
    Reply  02 Dec 2021, Stefan Ritt, Forum, Sequencer error with ODB Inc 
Thanks for reporting that bug. Indeed there was a problem in the sequencer code which I fixed now. Please try the updated develop branch.

Stefan
Entry  29 Oct 2021, Frederik Wauters, Bug Report, midas::odb::iterator + operator 
I have 16 array odb key

{"FIR Energy", {
            {"Energy Gap Value", std::array<uint32_t,16>(10) },

I can get the maximum of this array like 


uint32_t max_value = *std::max_element(values.begin(),values.end());

but when I need the maximum of a sub range

uint32_t max_value = *std::max_element(values.begin(),values.begin()+4);

I get

/home/labor/new_daq/frontends/SIS3316Module.cpp:584:62: error: no match for ‘operator+’ (operand types are ‘midas::odb::iterator’ and ‘int’)
  584 |   max_value = *std::max_element(values.begin(),values.begin()+4);
      |                                                ~~~~~~~~~~~~~~^~
      |                                                            |  |
      |                                                            |  int
      |               

As the + operator is overloaded for midas::odb::iterator, I was expected this to work.

(and yes, I can find the max element by accessing the elements on by one)
    Reply  29 Oct 2021, Frederik Wauters, Bug Report, midas::odb::iterator + operator | work around 
ok, so retrieving as a std::array (as it was defined) does not work

    std::array<uint32_t,16> avalues = settings["FIR Energy"]["Energy Gap Value"];

but retrieving as an std::vector does, and then I have a standard c++ iterator which I can use in std stuff

    std::vector<uint32_t> values = settings["FIR Energy"]["Energy Gap Value"];

> I have 16 array odb key
> 
> {"FIR Energy", {
>             {"Energy Gap Value", std::array<uint32_t,16>(10) },
> 
> I can get the maximum of this array like 
> 
> 
> uint32_t max_value = *std::max_element(values.begin(),values.end());
> 
> but when I need the maximum of a sub range
> 
> uint32_t max_value = *std::max_element(values.begin(),values.begin()+4);
> 
> I get
> 
> /home/labor/new_daq/frontends/SIS3316Module.cpp:584:62: error: no match for ‘operator+’ (operand types are ‘midas::odb::iterator’ and ‘int’)
>   584 |   max_value = *std::max_element(values.begin(),values.begin()+4);
>       |                                                ~~~~~~~~~~~~~~^~
>       |                                                            |  |
>       |                                                            |  int
>       |               
> 
> As the + operator is overloaded for midas::odb::iterator, I was expected this to work.
> 
> (and yes, I can find the max element by accessing the elements on by one)
Entry  25 Oct 2021, Francesco Renga, Forum, Logger crash 
Hello,
     I'm experiencing crashes of the mlogger program on the time scale of a couple 
of days. The only messages from MIDAS are:

05:34:47.336 2021/10/24 [mhttpd,INFO] Client 'Logger' (PID 14281) on database 
'ODB' removed by db_cleanup called by cm_periodic_tasks (idle 10.2s,TO 10s)
05:34:47.335 2021/10/24 [mhttpd,INFO] Client 'Logger' on buffer 'SYSMSG' removed 
by cm_periodic_tasks (idle 10.2s, timeout 10s)

Any suggestion to further investigate this issue?

Thank you very much,
         Francesco
    Reply  25 Oct 2021, Stefan Ritt, Forum, Logger crash 
The short term solution would be to increase the logger timeout in the ODB under

/Programs/Logger/Watchdog timeout

and set it to 6000 (one minute). But that is curing just the symptoms. It would be 
interesting to understand the cause of this error. Probably the logger takes more than 10 
seconds to start or stop the run. The reason could be that the history grow too big (what 
we have right now in MEG II), or some disk problems. But that needs detailed debugging on 
the logger side.

Stefan
Entry  14 Oct 2021, Amy Roberts, Suggestion, Adding (or improving discoverability) of TID for odbset 
Creating an ODB key requires users to know the Type ID that are defined in 
https://bitbucket.org/tmidas/midas/src/develop/include/midas.h starting at line 320.

I can't find any information on the Midas Wiki about these values or how to find 
them.

Am I missing something obvious?  Is there a way to improve how to find these values?  
Or is this not the best way to interact with the ODB?
    Reply  15 Oct 2021, Stefan Ritt, Suggestion, Adding (or improving discoverability) of TID for odbset 
> Creating an ODB key requires users to know the Type ID that are defined in 
> https://bitbucket.org/tmidas/midas/src/develop/include/midas.h starting at line 320.
> 
> I can't find any information on the Midas Wiki about these values or how to find 
> them.
> 
> Am I missing something obvious?  Is there a way to improve how to find these values?  
> Or is this not the best way to interact with the ODB?

Well, you found them in midas.h, so where is the problem?

If you want a more detailed description, just look in the midas documentation (RTFM):

https://midas.triumf.ca/MidasWiki/index.php/Midas_Data_Types

If you want a more modern interface to the ODB without these data types, look here:

https://midas.triumf.ca/MidasWiki/index.php/Odbxx

Best regards,
Stefan
Entry  11 Oct 2021, Konstantin Olchanski, Forum, midas forum updated, moved 
The midas forum software (elogd) was updated to latest version and moved from our old server 
(ladd00.triumf.ca) to our new server (daq00.triumf.ca).

The following URLs should work:

https://daq00.triumf.ca/elog-midas/Midas/ (new URL)
https://midas.triumf.ca/elog/Midas/ (old URL, redirects to daq00)
https://midas.triumf.ca/forum (link from midas wiki)

The configuration on the old server ladd00.triumf.ca is quite tangled between
several virtual hosts and several DNS CNAMEs. I think I got all the redirects
correct and all old URLs and links in old emails & etc still work.

If you see something wrong, please reply to this message here or email me directly.

K.O.
Entry  11 Oct 2021, Konstantin Olchanski, Forum, test 
test, no email. K.O.
    Reply  11 Oct 2021, Konstantin Olchanski, Forum, test 
> test, no email. K.O.

test reply, no email. K.O.
       Reply  11 Oct 2021, Konstantin Olchanski, Forum, test image.png
> > test, no email. K.O.
> 
> test reply, no email. K.O.

test attachment, no email. K.O.
          Reply  11 Oct 2021, Konstantin Olchanski, Forum, test 
> > > test, no email. K.O.
> > 
> > test reply, no email. K.O.
> 
> test attachment, no email. K.O.

test email. K.O.
Entry  11 Oct 2021, Stefan Ritt, Info, Modification in the history logging system 
A requested change in the history logging system has been made today. Previously, history values were
logged with a maximum frequency (usually once per second) but also with a minimum frequency, meaning
that values were logged for example every 60 seconds, even if they did not change. This causes a problem.
If a frontend is inactive or crashed which produces variables to be logged, one cannot distinguish between
a crashed or inactive frontend program or a history value which simply did not change much over time.
The history system was designed from the beginning in a way that values are only logged when they actually
change. This design pattern was broken since about spring 2021, see for example this issue:

https://bitbucket.org/tmidas/midas/issues/305/log_history_periodic-doesnt-account-for

Today I modified the history code to fix this issue. History logging is now controlled by the value of 
common/Log history in the following way:

* Common/Log history = 0 means no history logging
* Common/Log history = 1 means log whenever the value changes in the ODB
* Common/Log history = N means log whenever the value changes in the ODB and 
  the previous write was more than N seconds ago

So most experiments should be happy with 0 or 1. Only experiments which have fluctuating values due to noisy 
sensors might benefit from a value larger than 1 to limit the history logging. Anyhow this is not the preferred 
way to limit history logging. This should be done by the front-end limiting the updates to the ODB. Most of the 
midas slow control drivers have a “threshold” value. Only if the input changes by more then the threshold are 
written to the ODB. This allows a per-channel “dead band” and not a per-event limit on history logging 
as ‘log history’ would do. In addition, the threshold reduces the write accesses to the ODB, although that is
only important for very large experiments.

Stefan
Entry  29 Sep 2021, Richard Longland, Bug Report, nstall clash between MIDAS 2020-08 and mscb 
Thank you, Stefan.

I found these instructions under
1) The changelog: https://midas.triumf.ca/MidasWiki/index.php/Changelog#2020-12
2) Konstantin's elog announcements (e.g. https://midas.triumf.ca/elog/Midas/2089)

I do see reference to updating the submodules under the TRIUMF install 
instructions 
(https://midas.triumf.ca/MidasWiki/index.php/Setup_MIDAS_experiment_at_TRIUMF#Inst
all_MIDAS) although perhaps it can be clarified.

Cheers,
Richard
    Reply  29 Sep 2021, Stefan Ritt, Bug Report, nstall clash between MIDAS 2020-08 and mscb 
> Thank you, Stefan.
> 
> I found these instructions under
> 1) The changelog: https://midas.triumf.ca/MidasWiki/index.php/Changelog#2020-12
> 2) Konstantin's elog announcements (e.g. https://midas.triumf.ca/elog/Midas/2089)
> 
> I do see reference to updating the submodules under the TRIUMF install 
> instructions 
> (https://midas.triumf.ca/MidasWiki/index.php/Setup_MIDAS_experiment_at_TRIUMF#Inst
> all_MIDAS) although perhaps it can be clarified.
> 
> Cheers,
> Richard

Hi Richard,

I updated the documentation at

https://midas.triumf.ca/MidasWiki/index.php/Changelog#Updating_midas

by putting the submodule update command everywhere.

Best,
Stefan
Entry  28 Sep 2021, Richard Longland, Bug Report, Install clash between MIDAS 2020-08 and mscb 
All,

I am performing a fresh install of MIDAS on an Ubuntu linux box. I follow the 
usual installation procedure:

1) git clone https://bitbucket.org/tmidas/midas --recursive
2) cd midas
3) git checkout release/midas-2020-08
4) mkdir build
5) cd build
6) cmake ..
7) make

Step 3 warns me that 
"warning: unable to rmdir 'manalyzer': Directory not empty" and 
"warning: unable to rmdir 'midasio': Directory not empty"

Step 7 fails.
Compilation fails with an mhttp error related to mscb:
mhttpd.cxx:8224:59: error: too few arguments to function 'int mscb_ping(int, 
short unsigned int, int, int)'
 8224 |             status = mscb_ping(fd, (unsigned short) ind, 1);


I was able to get around this by rolling mscb back to some old version (commit 
74468dd), but am extremely nervous about mix-and-matching the code this way.

Any advice would be greatly appreciated.

Cheers,
Richard 
    Reply  28 Sep 2021, Stefan Ritt, Bug Report, Install clash between MIDAS 2020-08 and mscb 
> 1) git clone https://bitbucket.org/tmidas/midas --recursive
> 2) cd midas
> 3) git checkout release/midas-2020-08
> 4) mkdir build
> 5) cd build
> 6) cmake ..
> 7) make

When you do step 3), you get

~/tmp/midas$ git checkout release/midas-2020-08
warning: unable to rmdir 'manalyzer': Directory not empty
warning: unable to rmdir 'midasio': Directory not empty
M	mjson
M	mscb
M	mvodb
M	mxml

The 'M' in front of the submodules like mscb tell you that you
have an older version of midas (namely midas-2020-08), but the 
*current* submodules, which won't match. So you have to roll back
also the submodules with:

3.5) git submodule update --recursive

This fetched those versions of the submodules which match the
midas version 2020-08. See here for details: 

https://git-scm.com/book/en/v2/Git-Tools-Submodules

From where did you get the command

git checkout release/xxxx ???

If you tell me the location of that documentation, I will take
care that it will be amended with the command

git submodule update --recursive

Best,
Stefan
Entry  19 Sep 2021, Stefan Ritt, Bug Fix, Chat working again Screenshot_2021-09-19_at_21.27.19_.png
Not sure how many people are using it, but the Chat facility in midas was broken 
for some time now and got fixed today again.

Just for your information: Chat can be used like WhatsApp & Co, and connects all 
people who access a midas experiment through their browser. It's good to 
communicate between shift crew members located at different places. One advantage 
is that the chat messages can get 'spoken' by the text-to-speech engine of your 
browser, so it can be used to "wake up" shifters. Can be configured through the 
"Config" page.

Stefan
Entry  06 Sep 2021, Andreas Suter, Forum, mhttpd crash 
midas version used: midas-2019-05-cxx-1461-g906be8b

I find in the systemd log every couple of days/weeks the following error message related to the mhttpd:

[mhttpd,ERROR] [mhttpd.cxx:18886:on_work_complete,ERROR] Should not send response to request from socket 28 to socket 26, abort!

with various socket numbers of course.

Can anybody hint me what is going wrong here?

The bad thing on the crash is, that sometimes it is leading to a "chain-reaction" killing multiple midas frontends, which essentially stop the experiment.

Help would be very much appreciated!

Andreas 
    Reply  06 Sep 2021, Konstantin Olchanski, Forum, mhttpd crash 
> [mhttpd,ERROR] [mhttpd.cxx:18886:on_work_complete,ERROR] Should not send response to request from socket 28 to socket 26, abort!
> Can anybody hint me what is going wrong here?
> The bad thing on the crash is, that sometimes it is leading to a "chain-reaction" killing multiple midas frontends, which essentially stop the experiment.

This is my code. I am the culprit. I had a bit of discussion about this with Stefan.

Bottom line is something is rotten in the multithreading code inside mhttpd and under conditions unknown,
it sends the wrong data into the wrong socket. This causes midas web pages to be really confused (RPC replies
processed as CSS file, HTML code processed at RPC replies, a mess), this wrong data is cached by the browser,
so restarting mhttpd does not fix the web pages. So a mess.

I find this is impossible to replicate, and so cannot debug it, cannot fix it. Best I was able to do
is to add a check for socket numbers, and thankfully it catches the condition before web browser caches
become poisoned. So, broken web pages replaced by mhttpd crash.

This situation reinforces my opinion that multi-threading and C++ classes "do not mix" (like H2 and O2 do not mix).
If you write a multithreaded C++ program and it works, good for you, if there is a malfunction, good luck with it,
C++ just does not have any built-in support for debugging typical multithreading problems. I think others have come
to the same conclusion and invented all these new "safe" programming languages, like Rust and Go.

Back to your troubles.

1) If you see a way to replicate this crash, or some way to reliably cause
the crash within 5-10 minutes after starting mhttpd, please let me know. I can work with that
and I wish to fix this problem very much.

2) My "wrong socket" check calls abort() to produce a core dump. In my experience these core dumps
are useless for debugging the present problem. There is just no way to examine the state of each
thread and of each http request using gdb by hand.

3) this abort() causes linux to write a core dump, this takes a long time and I think it causes
other MIDAS program to stop, timeout and die. You can try to fix this by disabling core dumps (set "enable core dumps"
to "false" in ODB and set core dump size limit to 0), or change abort() to exit(). (You can also disable
the "wrong socket" check, but most likely you will not like the result).

4) run mhttpd inside a script: "while (1) { start mhttpd; sleep 1 sec; rinse, repeat; }" (run mhttpd without "-D", yes?)

In other news, the mongoose web server library have a new version available, they again changed their
multithreading scheme (I think it is an improvement). If I update mhttpd to this new version, it is very
likely the code with the "wrong socket" bug will be deleted. (with new bugs added to replace old bugs, of course).

K.O.
       Reply  07 Sep 2021, Andreas Suter, Forum, mhttpd crash 
Dear Konstantin,

thanks for the prompt response, this helps a lot!

> 1) If you see a way to replicate this crash, or some way to reliably cause
> the crash within 5-10 minutes after starting mhttpd, please let me know. I can work with that
> and I wish to fix this problem very much.

I wished I could! This happens 3-4 times per year only, so close to impossible to trigger.

> 2) My "wrong socket" check calls abort() to produce a core dump. In my experience these core dumps
> are useless for debugging the present problem. There is just no way to examine the state of each
> thread and of each http request using gdb by hand.
> 
> 3) this abort() causes linux to write a core dump, this takes a long time and I think it causes
> other MIDAS program to stop, timeout and die. You can try to fix this by disabling core dumps (set "enable core dumps"
> to "false" in ODB and set core dump size limit to 0), or change abort() to exit(). (You can also disable
> the "wrong socket" check, but most likely you will not like the result).
> 

I changed now to exit() rather than abort on the production machine. Perhaps this should be the default?

Andreas
          Reply  17 Sep 2021, Stefan Ritt, Forum, mhttpd crash mhttpdScreenshot_2021-09-17_at_21.11.15_.png
To limit the impact of the numerous crashes of mhttpd, I installed the monit tool at MEG at PSI 
(https://en.wikipedia.org/wiki/Monit). It monitors mhttpd, and if it cannot connect to it for a certain
time, it kills the process and restarts it. This covers endless loops, simple crashes (caused by the
known multi-threading issue in mongoose), and also cases where mhttpd develops a memory leak and becomes
unresponsive. 

To configure monit for mhttpd, first install the package, make sure the daemon gets started automatically
after reboot (typically "sysemctl enable monit"), and put the attached file into

/etc/monit.d/mhttpd

You have to adjust the <path-to-midas> according to your midas installation, and probably also the port
under which mhttpd is listening (8082 in my case). Put 

set daemon 10

into /etc/monitrc if you want monit to check mhttpd every 10 seconds (default is 30 seconds). Then, every
10 seconds monit request "midas.css" from mhttpd, and if it cannot obtain it after 30 seconds, it kills
mhttpd and restarts it.

Loading long history plots taking more than 30 seconds should probably not be an issue since mhttpd is 
multi-threaded, but I haven't tested this in detail.

Attached below is a typical status page produced by monit, which has its own built-in web server (normally
listening at port 2812, accessible only from localhost by default).

I hope this helps some of you.

Stefan
Entry  24 Jun 2021, Konstantin Olchanski, Bug Fix, changes in history plots 
I am updating the history plots. Main changes:

- the old history display code should again be easily usable (use the "open in old history display" checkbox)
- the history plot editor has an "edit in ODB" button that takes as to the plot definition in ODB (sometimes it is 
easier to editing things in the ODB editor)
- error in history plot editor that created "formula" entry of incorrect size should be fixed
- "reorder" (and "delete entry") functions in the history plot editor should work again (plus added explanation text)
- "factor" and "offset" restored in the history plot editor
- added the long desired "voffset" to simplify plot scaling and positioning
- (factor, offset and voffset do not yet work in the new history plots, TBI ASAP)
- history plot editor and generate_hist_graph() now use the same code to read plot definitions from ODB. There should 
be no more confusion about content of history plot entries in ODB and what each entry is supposed to do.

These changes have been precipitated by our inability to plot high voltage voltage and current on the same plot,
see bug https://bitbucket.org/tmidas/midas/issues/308/history-plot-formula-cannot-be-used-to

Voltage is in the range 0..1000 (volts) and current is in the range 0..50 and 0..0.100, autoscaling on voltage
makes the currents invisible at the zero line. In the past, we used the "factor" setting to scale
the graphs so we can see both voltage and currents at the same time (currents scaled up by factor 25 and 600,
as example).

The new "formula" feature was supposed to replace (and improve upon) the "factor" and "offset". But if I use
the formula "x*25", suddenly the plot is telling us that current values are not 50 uA, but 1250 uA (50*25),
and this is just wrong. We do not want to scale the micro-amps, we want to better position the plot on the graph,
like the old "factor" and "offset" allowed us to do.

So the idea is to use this computation:

y_position_on_plot = offset + factor*(formula(history_value) - voffset)

- "formula" is to transform history values into physical values (i.e. pressure meter reports bars, but we want atm, or 
voltmeter is reading in discrete units of 0.125V, we want to see volts)
- "factor" and "offset" is to position the graphs on the plot for best visual presentation of data
- I also added is the much desired "voffset", you only know it is needed if you have a non-zero "offset" and you need 
to change the "factor", surprise, "offset" has ot be changed, too, and good luck recalculating it correctly in one 
try.

The way to use this stuff:
- adjust "voffset" to bring the graph to around y=0
- increase the "factor" to zoom-in on features and stuff
- adjust "offset" to move the graph up and down relative to all the other graphs on the plot
- now one can zoom in and out as needed by changing the "factor" and the plot will stay roughly in the right place 
without having to readjust the offsets.

K.O.
    Reply  24 Jun 2021, Stefan Ritt, Bug Fix, changes in history plots 
I disagree with the proposed change to scale the HV current for a "nice" display. If values are scaled, the axis should be 
scaled in the same way. Otherwise people might read the current from the plot, look at the axis, and again get the wrong 
value (the factor of 25x you mention). Sure you can hover with the cursor over the graph, and see the right value, but think 
of taking a screen shot, putting this into a publication, and get complaints from the reviewer.

The only "correct" way in my opinion is to implement two vertical axis, as can be seen in some papers. One for the HV, and a 
new TBD right axis for the current values, then indicating for each graph if the left or right vertical axis applies. For 
the secondary axis we can have autoscaling or fixed scaling, as we have for the primary axis.

Stefan
       Reply  25 Jun 2021, Marco Francesconi, Bug Fix, changes in history plots 
We are using the new history formula as a quick way to convert signals from sensors to actual physical values (for example Voltage->Temperature, Voltage->relative humidity 
...), so it is great that the shown voltage is the calculated one.

I would like to add a point to this discussion.
In our collaboration people attach images of history plots to elogs, meeting presentation and/or physical logbooks.
The proposed scaling formula may work fine online using the cursors, but, once an image is created, I do not understand how it is possible to extract the value for a scaled 
variables.
Suppose you see a graph in a presentation with a current increase by some PSU and the current was scaled to be in the same plot of the voltage.
Looking at the delta in the image, how can you judge the current increase without any axis/grid to refer to?

So I support Stefan proposal for a secondary axis, as long as it is clear which value belong to which axis.
Maybe marking the channels in the description or using different line styles/thickness?

Best,
Marco
          Reply  25 Jun 2021, Konstantin Olchanski, Bug Fix, changes in history plots 
I will have to post an example of a scaled plot. I figure everybody forgot how they look like.

K.O.


> We are using the new history formula as a quick way to convert signals from sensors to actual physical values (for example Voltage->Temperature, Voltage->relative humidity 
> ...), so it is great that the shown voltage is the calculated one.
> 
> I would like to add a point to this discussion.
> In our collaboration people attach images of history plots to elogs, meeting presentation and/or physical logbooks.
> The proposed scaling formula may work fine online using the cursors, but, once an image is created, I do not understand how it is possible to extract the value for a scaled 
> variables.
> Suppose you see a graph in a presentation with a current increase by some PSU and the current was scaled to be in the same plot of the voltage.
> Looking at the delta in the image, how can you judge the current increase without any axis/grid to refer to?
> 
> So I support Stefan proposal for a secondary axis, as long as it is clear which value belong to which axis.
> Maybe marking the channels in the description or using different line styles/thickness?
> 
> Best,
> Marco
       Reply  25 Jun 2021, Konstantin Olchanski, Bug Fix, changes in history plots 
> I disagree ...

I am happy with disagreement and differences of opinions. Zest of life, driver of progress and improvements, etc.

I am even more happy with solutions to problems. The current problem is that the offset and factor feature
of history plots has been removed without much discussion.

I stress, we have been using this feature to run experiments for the last 20 years.

I do not understand objections to it being restored. If you do not want to use it, do not use it.

K.O.

> with the proposed change to scale the HV current for a "nice" display. If values are scaled, the axis should be 
> scaled in the same way. Otherwise people might read the current from the plot, look at the axis, and again get the wrong 
> value (the factor of 25x you mention). Sure you can hover with the cursor over the graph, and see the right value, but think 
> of taking a screen shot, putting this into a publication, and get complaints from the reviewer.
> 
> The only "correct" way in my opinion is to implement two vertical axis, as can be seen in some papers. One for the HV, and a 
> new TBD right axis for the current values, then indicating for each graph if the left or right vertical axis applies. For 
> the secondary axis we can have autoscaling or fixed scaling, as we have for the primary axis.
> 
> Stefan
          Reply  25 Jun 2021, Konstantin Olchanski, Bug Fix, changes in history plots 
> > The only "correct" way in my opinion is to implement two vertical axis, as can be seen in some papers. One for the HV, and a 
> > new TBD right axis for the current values, then indicating for each graph if the left or right vertical axis applies. For 
> > the secondary axis we can have autoscaling or fixed scaling, as we have for the primary axis.

In the past, we have done some useful plots with maybe 10 variables plotted
at the same time with different scaling and positioning on the graph.

Having 2 vertical axis is maybe useful for the specific case of plotting high voltages,
but not in the general case.

Actually, just 2 vertical axis will not work to plot high voltages in ALPHA-g, because
we have anode currents on the scale 0..0.1 uA and cathode currents on the scale 50..60 uA.

K.O.
    Reply  25 Jun 2021, Stefan Ritt, Bug Fix, changes in history plots 
A general warning: With the recent history changes implemented in the develop branch, starting from a fresh ODB and editing 
any history panel, on gets tons of errors and debug output from mhttpd:

MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Minimum" returned status 312
MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Minimum" returned status 312
MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Maximum" returned status 312
MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Maximum" returned status 312
MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Zero ylow" returned status 312
MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Log axis" returned status 312
MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Zero ylow" returned status 312
Load from ODB History/Display/Default/Trigger rate: hist plot: 2 variables
timescale: 1h, minimum: 0.000000, maximum: 0.000000, zero_ylow: 0, log_axis: 0, show_run_markers: 1, show_values: 1, 
show_fill: 1
var[0] event [System][Trigger per sec.] formula [], colour [#00AAFF] label [] factor 1.000000 offset 0.000000 voffset 
0.000000 order 10
var[1] event [System][Trigger kB per sec.] formula [], colour [#FF9000] label [] factor 1.000000 offset 0.000000 voffset 
0.000000 order 20



This has to be fixed by the original author. I strongly recommend to make such modifications on a separate branch not to 
break running experiments.

Stefan
       Reply  25 Jun 2021, Konstantin Olchanski, Bug Fix, changes in history plots 
> A general warning: With the recent history changes implemented in the develop branch, starting from a fresh ODB and editing 
> any history panel, on gets tons of errors and debug output from mhttpd: ...

This is the reason most projects have separate development and production branches.

I recommend everybody to use the released tagged versions of midas for production.

> I strongly recommend to make such modifications on a separate branch not to 
> break running experiments.

Is there something that does not work anymore? Did I break something? The debug messages I am still
tuning.

K.O.


> 
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Minimum" returned status 312
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Minimum" returned status 312
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Maximum" returned status 312
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Maximum" returned status 312
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Zero ylow" returned status 312
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Log axis" returned status 312
> MVOdb: Error: MIDAS db_get_value() at ODB path "/History/Display/Default/Trigger rate/Zero ylow" returned status 312
> Load from ODB History/Display/Default/Trigger rate: hist plot: 2 variables
> timescale: 1h, minimum: 0.000000, maximum: 0.000000, zero_ylow: 0, log_axis: 0, show_run_markers: 1, show_values: 1, 
> show_fill: 1
> var[0] event [System][Trigger per sec.] formula [], colour [#00AAFF] label [] factor 1.000000 offset 0.000000 voffset 
> 0.000000 order 10
> var[1] event [System][Trigger kB per sec.] formula [], colour [#FF9000] label [] factor 1.000000 offset 0.000000 voffset 
> 0.000000 order 20
> 
> 
> 
> This has to be fixed by the original author. I strongly recommend to make such modifications on a separate branch not to 
> break running experiments.
> 
> Stefan
    Reply  30 Jun 2021, Konstantin Olchanski, Bug Fix, changes in history plots 
> I am updating the history plots.
> So the idea is to use this computation:
> y_position_on_plot = offset + factor*(formula(history_value) - voffset)

Stefan and myself did some brain storming on zoom. Writing it down the way I remember it.

- we distilled the gist of the problem - the numerical values we show in the plot labels and in hover-over-the-graph
are before formula is applied or after the formula is applied?

- I suggested a universal solution using a double formula: use formula1 for one case;
  use formula2 for the other case;
  use formula1 for "physics calibration", use formula2 for factor and offset for composite plots:
     numeric_value = formula1(history_value)
     plotted_value = formula2(numeric_value)

- we agree that this is way too complicated, difficult to explain and difficult to coherently present in the history editor

- Stefan suggested a simple solution, a checkbox labeled "show raw value" next to each history variable. by default, the 
value after the formula is plotted and displayed. if checked, the raw value (before the formula) is displayed, and the 
value after the formula is plotted. (so this works the same as the factor and offset on the old history plots).

- if "show raw value" is enabled, the numerical values shown will be inconsistent against the labels on the vertical axis. 
Our solution it to turn the axis labels off. (for composite plots, like oscillator frequency in Hz vs oscillator 
temperature in degC, both scaled to see their correlation, the vertical axis is unit-less "arbitrary units", of course)

- to simplify migration of old history plots that use custom factor and offset settings, we think in the direction of 
automatically moving them to the "formula". (factor=2, offset=10 automatically populates formula with "2*x+10", "show raw 
value" checked/enabled). Thus we can avoid implementing factor and offset in the new history code (an unwelcome 
complication).

- I think this covers all the use cases I have seen in the past, so we will move in this direction.

K.O.
       Reply  14 Jul 2021, Konstantin Olchanski, Bug Fix, changes in history plots 
Moving in the direction of this proposal. History plot editor is updated according to it. Remaining missing piece is the "show 
raw value" buttons and code behind them.

Changes:

- "show factor and offset" moved to the top of the page, "off" by default
- factor and offset (if not zero) are automatically migrated to the formula field (if it is empty), one needs to save the panel 
for this to take effect.

K.O.


> > I am updating the history plots.
> > So the idea is to use this computation:
> > y_position_on_plot = offset + factor*(formula(history_value) - voffset)
> 
> Stefan and myself did some brain storming on zoom. Writing it down the way I remember it.
> 
> - we distilled the gist of the problem - the numerical values we show in the plot labels and in hover-over-the-graph
> are before formula is applied or after the formula is applied?
> 
> - I suggested a universal solution using a double formula: use formula1 for one case;
>   use formula2 for the other case;
>   use formula1 for "physics calibration", use formula2 for factor and offset for composite plots:
>      numeric_value = formula1(history_value)
>      plotted_value = formula2(numeric_value)
> 
> - we agree that this is way too complicated, difficult to explain and difficult to coherently present in the history editor
> 
> - Stefan suggested a simple solution, a checkbox labeled "show raw value" next to each history variable. by default, the 
> value after the formula is plotted and displayed. if checked, the raw value (before the formula) is displayed, and the 
> value after the formula is plotted. (so this works the same as the factor and offset on the old history plots).
> 
> - if "show raw value" is enabled, the numerical values shown will be inconsistent against the labels on the vertical axis. 
> Our solution it to turn the axis labels off. (for composite plots, like oscillator frequency in Hz vs oscillator 
> temperature in degC, both scaled to see their correlation, the vertical axis is unit-less "arbitrary units", of course)
> 
> - to simplify migration of old history plots that use custom factor and offset settings, we think in the direction of 
> automatically moving them to the "formula". (factor=2, offset=10 automatically populates formula with "2*x+10", "show raw 
> value" checked/enabled). Thus we can avoid implementing factor and offset in the new history code (an unwelcome 
> complication).
> 
> - I think this covers all the use cases I have seen in the past, so we will move in this direction.
> 
> K.O.
          Reply  14 Jul 2021, Konstantin Olchanski, Bug Fix, changes in history plots 
> Moving in the direction of this proposal. Remaining missing piece is the "show 
> raw value" buttons and code behind them.

added "show raw value" button, updated on-page instructions.

I think this is the final layout of the history panel editor, conversion
to html+javascript will be done "as is". If you have suggestions to improve
the layout (add/remove/move things around, etc), please shoult out (on the elog
here or by direct email to me).

I am thinking in the direction of changing the control flow of the history editor:

- midas "history" manu button click redirects to
- current history panel selection (with checkbox to open old history plots), click on "new plot" button redirects to
- new page for creating new plots. this will present a list of all history variables, click on variable name creates a new history 
panel containing just this one variable and redirects to it.

In other words, to see the history for any history variable:
- click on "history" menu button
- click on "new"
- click on desired history variable
- see this history plot

From here, click on the "wheel" button to open the existing history panel editor and add any additional variables, change settings, 
etc.

In the history panel editor, I am thinking in the direction of replacing the existing drop-down selection of history variables (now 
very workable for large experiments) with an overlay dialog to show all history variables, with checkboxes to select them, basically 
the same history variable select page as described above. Not sure yet how this will work visually.

K.O.
             Reply  24 Aug 2021, Stefan Ritt, Bug Fix, changes in history plots 
One addition I would be in favour of is to remove the "Order" and replace it with drag&drop handles, because this is what people are more 
used to today. Only the old guys like us remember the /etc/init.d/xx_yy scheme where one uses an integer number in the file name to 
determine an order. 

See for example: https://jsbin.com/hijetos/edit?js,output

But instead of relying on a foreign library, I would rather implement that myself, since I need the same thing later for the to-be-
implemented ODB editor (next year? next lockdown?)

Stefan
ELOG V3.1.4-2e1708b5