Dear all,

I have a "slow control" frontend which reads out 100 slow control parameters.
When I'm interactively adding a parameter to a history plot, 
a nice "Add history variable" pops up .. , but with 100 parameters in the list, 
it doesn't fit within the screen... 

The browser becomes passive, and I didn't find any easy way of scrolling.

In the attached example, adding a channel 32 variable becomes rather cumbersome, 
not speaking about channel 99.

Two questions:

a) how do people get around this "no-scrolling" issue? - perhaps there is a workaround

b) how big of a deal is it to add a scroll bar to the "Add history variables" popup ? 
   - I do not know javascript myself, but could find help to contribute..

-- many thanks, regards, Pasha

We switched from the history files from MIDAS to FILE, so we have *.dat files now (per variable), instead of the old *.hst. 

How shoul
d one now extract data from these data files? With the old *,hst files I can e.g. mhdump -E 102 231010.hst 

but with the new *.dat files I get

...2023/history$ mhdump -E 0 -T "Run number" mhf_1697445335_20231016_run_transitions.dat | head -n 15
event name: [Run transitions], time [1697445335]
tag: tag: /DWORD 1 4 /timestamp
tag: tag: UINT32 1 4 State
tag: tag: UINT32 1 4 Run number
record size: 12, data offset: 1024
record 0, time 1697557722, incr 112387
record 1, time 1697557783, incr 61
record 2, time 1697557804, incr 21
record 3, time 1697557834, incr 30
record 4, time 1697557888, incr 54
record 5, time 1697558318, incr 430
record 6, time 1697558323, incr 5
record 7, time 1697558659, incr 336
record 8, time 1697558668, incr 9
record 9, time 1697558753, incr 85

not very intelligible

Yes, I can do csv export on the webpage. But it would be nice to be able to extract from just the files. Also, the webpage export only saves the data shown ( range limited and/or downsampled)

> Hi Stefan, thanks a lot !
> 
> I just thought that for the EQ_SLOW type equipment calls to sleep() could be hidden in mfe.cxx 
> and handled based on the requested frequency of the history updates.

Most people combine EQ_SLOW with EQ_POLLED, so they want to read out as quickly as possible. Since 
the framework cannot "guess" what the users want there, I removed all sleep() in the framework.



> Doing the same in the user side is straighforward - the important part is to know where the 
> responsibility line goes (: smile :) 


Pushing this to the user gives you more freedom. Like you can add sleep() for some frontends, but not 
for others, only when the run is stopped and more.

Stefan

Hi Stefan, thanks a lot !

I just thought that for the EQ_SLOW type equipment calls to sleep() could be hidden in mfe.cxx 
and handled based on the requested frequency of the history updates.

Doing the same in the user side is straighforward - the important part is to know where the 
responsibility line goes (: smile :) 

-- regards, Pasha

Put a 

  ss_sleep(10);

into your frontend_loop(), then you should be fine.

The event loop runs as fast as possible in order not to miss any (triggered) event, so no seep in the 
event loop, because this would limit the (triggered) event rate to 100 Hz (minimum sleep is 10 ms). 
Therefore, you have to slow down the event loop manually with the method described above.

Best,
Stefan

Dear all,

I have implemented a number of slow control frontends which are directed to update the 
history once in every 10 sec, and they do just that. 

I expected that such frontends would be spending most of the time sleeping and waking up 
once in ten seconds to call their respective drivers and send the data to the server. 

However I observe that each frontend process consumes almost 100% of a single core CPU time 
and the frontend driver is called many times per second. 

Is that the expected behavior ?

So far, I couldn't find the place in the system part of the frontend code (is that the right 
place to look for?) which regulates the frequency of the frontend driver calls, so I'd greatly 
appreciate if someone could point me to that place.

I'm using the following commit:

commit 30a03c4c develop origin/develop Make sure line numbers and sequence lines are aligned.

-- many thanks, regards, Pasha

> I found the first issue: The link to
> https://midas.triumf.ca/MidasWiki/index.php/Custom_plots_with_mplot

fixed.

https://midas.triumf.ca/Custom_plots_with_mplot

also works.

I tried to get rid of redirect to daq00 completely and make the whole MidasWiki show up 
under midas.triumf.ca, but discovered/remembered that I cannot do this without changing 
MidasWiki config [$wgServer = "https://daq00.triumf.ca";] which causes mediawiki to 
redirect everything to daq00 (using the 301 "moved permanently" reply, ouch!). In theory, 
if I change it to "https://midas.triumf.ca" it will redirect everything there instead, 
but I am hesitant to make this change. It has been like this since forever and I have no 
idea what else will break if I change it.

K.O.

> > git pull
> > git submodule update
> 
> confirmed. just run into this myself. I think "make" should warn about out of 
> date git modules. Also check that the build git version is tagged with "-dirty".
> 
> K.O.

The submodule business becomes kind of annoying. I updated the documentation at

https://daq00.triumf.ca/MidasWiki/index.php/Quickstart_Linux#MIDAS_Package_Installatio
n

to tell people to use 

1) "git clone ... --recurse-submodules" during the first clone
2) "git submodule update --init --recursive" in case they forgot 1)
3) "git pull --recurse-submodules" for each update or to use
4) "git config submodule.recurse true" to make the --recurse-submodules the default

I use 4) since a while and it works nicely, so one does not have to remember to pull 
recursively each time.

Stefan

> the DNS alias for midas.triumf.ca moved from old ladd00.triumf.ca to new 
> daq00.triumf.ca. same as before it redirects to the MidasWiki and to the midas 
> forum (elog) that moved from ladd00 to daq00 quite some time ago. if you see any 
> anomalies in accessing them (broken links, bad https certificates), please report 
> them to this forum or to me directly at olchansk@triumf.ca. K.O.

I found the first issue: The link to

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

does not work any more. The link

https://daq00.triumf.ca/MidasWiki/index.php/Custom_plots_with_mplot

however does work. Same with

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

and

https://daq00.triumf.ca/MidasWiki/index.php/Sequencer

I have a few cases in mhttpd where I link directly to our documentation. I prefer
to have those link with "midas.triumf.ca" instead of "daq00.triumf.ca" in case you
change the machine again in the future.

Best,
Stefan

the DNS alias for midas.triumf.ca moved from old ladd00.triumf.ca to new 
daq00.triumf.ca. same as before it redirects to the MidasWiki and to the midas 
forum (elog) that moved from ladd00 to daq00 quite some time ago. if you see any 
anomalies in accessing them (broken links, bad https certificates), please report 
them to this forum or to me directly at olchansk@triumf.ca. K.O.

> git pull
> git submodule update

confirmed. just run into this myself. I think "make" should warn about out of 
date git modules. Also check that the build git version is tagged with "-dirty".

K.O.

MidasWiki was updated to current mediawiki LTS 1.39.6 supported until Nov 2025, 
see https://www.mediawiki.org/wiki/Version_lifecycle

as downside, after this update, I see large amounts of "account request" spam, 
something that did not exist before. I suspect new mediawiki phones home to 
subscribe itself to some "please spam me" list.

if you want a user account on MidasWiki, please email me or Stefan directly, we 
will make it happen.

K.O.

Custom plots including scatter, histogram and color map plots have been 
implemented. This lets you plot graphs of X/Y data or histogram data stored in the 
ODB on a custom page. For some examples and documentation please go to

https://daq00.triumf.ca/MidasWiki/index.php/Custom_plots_with_mplot

Enjoy!
Stefan

> Also, I think that having a sine wave displayed by midas/examples/slowcont/scfe.cxx 
> would make this example even more helpful.

Indeed. I reworked the example to have a out-of-the-box sine wave plotter, including the
automatic creation of a history panel. Thanks for the hint.

Best,
Stefan

Hi Sfefan, thanks a lot for taking time to reproduce the issue! 

Here comes the resolution, and of course, it was something deeply trivial :  

the definition of the HV equipment in midas/examples/slowcont/scfe.cxx has 
the history logging time in seconds, however the comment suggests milliseconds (see below), 
and for a few days I believed to the comment (:smile:)

Easy to fix. 

Also, I think that having a sine wave displayed by midas/examples/slowcont/scfe.cxx 
would make this example even more helpful.

-- thanks again, regards, Pasha

--------------------------------------------------------------------------------------------------------
EQUIPMENT equipment[] = {

   {"HV",                       /* equipment name */
    {3, 0,                      /* event ID, trigger mask */
     "SYSTEM",                  /* event buffer */
     EQ_SLOW,                   /* equipment type */
     0,                         /* event source */
     "FIXED",                   /* format */
     TRUE,                      /* enabled */
     RO_RUNNING | RO_TRANSITIONS,        /* read when running and on transitions */
     60000,                     /* read every 60 sec */
     0,                         /* stop run after this event limit */
     0,                         /* number of sub events */
     10000,                     /* log history at most every ten seconds */ // <------------ this is 10^4 seconds, not 10 seconds
     "", "", ""} ,
    cd_hv_read,                 /* readout routine */
    cd_hv,                      /* class driver main routine */
    hv_driver,                  /* device driver list */
    NULL,                       /* init string */
    },


https://bitbucket.org/tmidas/midas/src/7f0147eb7bc7395f262b3ae90dd0d2af0625af39/examples/slowcont/scfe.cxx#lines-81

Hello,

Since commit bc227a8a34def271a598c0200ca30d73223c3373 I've been getting the compilation error below (on a Raspberry Pi 3 Model B Plus Rev 1.3).

The fix is obvious from the reported error, but I am wondering whether this should be fixed in the main git??

Thanks,

Zaher

> > 3) Make /Sequencer/State/Path relative to <exp>/userfiles. Like if /Sequencer/State/Path=test would then result to a final directory <exp>/userfiles/sequencer/test
> > 
> > I'm kind of tempted to go with 3), since this allows the experiment to define different subdirectories under <exp>/userfiles/sequencer/... depending on the situation of the experiment.
> > 
> > Best,
> > Stefan
> 
> For me the option 3) seems the most coherent one.
> Andreas

Ok, I implemented option 3) above. This means everybody using the midas sequencer has to change /Sequencer/State/Path to an empty string and move the 
sequencer files under <exp>/userfiles/sequencer as a starting point. I tested most thing, including the INCLUDE statements, but there could still be
a bug here or there, so please give it a try and report any issue to me.

Best,
Stefan

First of all it's important to understand that the slow control system has nothing to do
with events. So if you look at event statistics, these are the events with the slow control
data sent to the midas data file, not the history database. So the logging period (the one you 
decreased from 60s to 10s to 6s) only affect the generation of events. 

What is important in your case is the number of events sent to the ODB. You see these in the
screen output of the slow control frontend (see attachment). This number show increase every
second.

I tried your modification (change nulldev with a sine function), and left the sc_fe.cxx
otherwise untouched. I then started with a fresh ODB ("rm /"). Started logger, mhttpd, sc_fe
and started a run. In the attachments is what I see. So I don't understand what your problem
is.

Dear MIDAS developers,

I'm trying to understand handling of the history (slow control) variables in MIDAS,
and it seems that the behavior I'm observing is somewhat counterintuitive. 
Most likely, I just do not understand the implemented logic.

As it it rather difficult to report on the behavior of the interactive program,
I'll describe what I'm doing and illustrate the report with the series of attached 
screenshots showing the history plots and the status of the run control at different 
consecutive points in time.

Starting with the landscape:

- I'm running MIDAS, git commit=30a03c4c (the latest, as of today).

- I have built the midas/examples/slowcont frontend with the following modifications.
  (the diffs are enclosed below):
  
  1) the frequency of the history updates is increased from 60sec/10sec to 6sec/1sec
     and, in hope to have updates continuos, I replaced (RO_RUNNING | RO_TRANSITIONS)
     with RO_ALWAYS.

  2) for convenience of debugging, midas/drivers/nulldrv.cxx is replaced with its clone,
     which instead of returning zeroes in each channel, generates a sine curve:

                  V(t) = 100*sin(t/60)+10*channel

- an active channel in /Logger/History is chosen to be FILE

- /History/LoggerHistoryChannel is also set to FILE 

- I'm running mlogger and modified, as described, 'scfe' frontend from midas/examples/slowcont

- the attached history plots include three (0,4 and 7) HV:MEASURED channels


Now, the observations:

1) the history plots are updated only when a new run starts, no matter how hard
   I'm trying to update them by clicking on various buttons.

   The attached screenshots show the timing sequence of the run control states
   (with the times printed) and the corresponding history plots. 

   The "measured voltages" change only when the next run starts - the voltage graphs 
   break only at the times corresponding to the vertical green lines.

2) No matter for how long I wait within the run, the history updates are not happening.

3) if the time difference between the two run starts gets too large,
   the plotted time dependence starts getting discontinuities

4) finally, if I switch the logging channel from FILE to MIDAS (activate the MIDAS
   channel in /Logger/History and set /History/LoggerHistoryChannel to MIDAS),
   the updates of the history plots simply stop.

MIDAS feels as a great DAQ framework, so I would appreciate any suggestion on 
what I could be doing wrong. I'd also be happy to give a demo in real time 
(via ZOOM/SKYPE etc).

-- much appreciate your time, thanks, regards, Pasha
    
------------------------------------------------------------------------------
diff --git a/examples/slowcont/scfe.cxx b/examples/slowcont/scfe.cxx
index 11f09042..c98d37e8 100644
--- a/examples/slowcont/scfe.cxx
+++ b/examples/slowcont/scfe.cxx
@@ -24,9 +24,10 @@
 #include "mfe.h"
 #include "class/hv.h"
 #include "class/multi.h"
-#include "device/nulldev.h"
 #include "bus/null.h"
 
+#include "nulldev.h"
+
 /*-- Globals -------------------------------------------------------*/
 
 /* The frontend name (client name) as seen by other MIDAS clients   */
@@ -74,11 +75,11 @@ EQUIPMENT equipment[] = {
      0,                         /* event source */
      "FIXED",                   /* format */
      TRUE,                      /* enabled */
-     RO_RUNNING | RO_TRANSITIONS,        /* read when running and on transitions */
-     60000,                     /* read every 60 sec */
+     RO_ALWAYS,        /* read when running and on transitions */
+     6000,                     /* read every 6 sec */
      0,                         /* stop run after this event limit */
      0,                         /* number of sub events */
-     10000,                     /* log history at most every ten seconds */
+     1000,                     /* log history at most every one second */
      "", "", ""} ,
     cd_hv_read,                 /* readout routine */
     cd_hv,                      /* class driver main routine */
@@ -93,8 +94,8 @@ EQUIPMENT equipment[] = {
      0,                         /* event source */
      "FIXED",                   /* format */
      TRUE,                      /* enabled */
-     RO_RUNNING | RO_TRANSITIONS,        /* read when running and on transitions */
-     60000,                     /* read every 60 sec */
+     RO_ALWAYS,        /* read when running and on transitions */
+     6000,                     /* read every 6 sec */
      0,                         /* stop run after this event limit */
      0,                         /* number of sub events */
      1,                         /* log history every event as often as it changes (max 1 Hz) */
------------------------------------------------------------------------------
[test_001]$ diff ../midas/examples/slowcont/nulldev.cxx ../midas/drivers/device/nulldev.cxx 
13d12
< #include <math.h>
150,154c149,150
<    if (channel < info->num_channels) {
<      // *pvalue = info->array[channel];
<      time_t t = time(NULL);;
<      *pvalue = 100*sin(M_PI*t/60)+10*channel;
<    }
---
>    if (channel < info->num_channels)
>       *pvalue = info->array[channel];
------------------------------------------------------------------------------