Below are the steps we used to increase the maximum number of frontends that we could run.

In midas.h

#define MAX_CLIENTS            64

changed to

#define MAX_CLIENTS            128

In msystem.h:

#define MAX_RPC_CONNECTION     64

changed to

#define MAX_RPC_CONNECTION     128

In odb.c:

assert(sizeof(BUFFER_HEADER) == 16444); 

GUESS: 256*64+60 = 16444, so change 64 to 128

changed to:                                                                                                                         

assert(sizeof(BUFFER_HEADER) == 32828); //256*128+60

 

DATABASE_HEADER = 64 + 64*DATABASE_CLIENT = 64 + 64*8256 = 528448

changed to:

DATABASE_HEADER = 64 + 128*DATABASE_CLIENT = 64 + 128*8256 = 1056832.

Hi. We've just updated our midas installation to the newest version, and we now see repeated errors from the 
mserver in messages. Mostly we see

11:17:02.994 2018/08/21 [ODBEdit,TALK] Program mserver restarted

which happens 2-3 times per minute. 

We have also been seeing occasional dropped rpc connections to our frontends, which could be related. 

The version we were running with previously was ~1 year old, and we have just updated to the newest version 
on bitbucket. 

Thanks,
Wes

Hi,

I am attempting to compile and run analysis code on a completely different,
unconnected system than the DAQ computer for the experiment. The analyzer was
developed previously and my goal is to get it running and then update it to
achieve my needs. Before compiling the analyzer, I load a backup ODB file in
odbedit, and compile experim.h. I then compile the analyzer with that experim.h
file. When I run the analyzer I get the following output:

> MIDAS version 2.1ROOT version 5.34/36Root server listening on port 9090...
> Running analyzer offline. Stop with "!"
> Configuration file "/somedir/switches.odb" loaded
> [Analyzer,INFO] Set run number 1290 in ODB
> Load ODB from run 1290...[Analyzer,INFO] cannot load value "Client Notify":
write protected
> [Analyzer,INFO] cannot load value "Prompt": write protected
.
.
.
> [Analyzer,INFO] cannot load value "LANSCE-ops": write protected
> MIDAS version 2.1ROOT version 5.34/36OK
> Configuration file "/somedir/switches.odb" loaded
> Data_Raw/run01290.mid.gz:16355  Data_Analyzed/run01290.root:15208  events, 0.43s

I have confirmed all files being used have read/write access to all users. The
analyzer does populate a .root output file with filled histograms, however not
all histograms are filled. I believe this is because histograms that relied on
an ODB paramater that failed to load did not populate. Any idea as to what I am
doing wrong or how I could resolve this issue are greatly appreciated.

Thanks,
William Moore

Hi,

I have been trying to use db_check_record() in order to verify that a subtree in the ODB has the correct 
variables, variable order, and overall size. I'm going off the documentation 
(https://midas.psi.ch/htmldoc/group__odbfunctionc.html) and use a string to compare against the ODB 
structure.  Since the string format is not specified for db_check_record(), I'm formatting my string 
according to the db_create_record() example.

Instead of db_check_record() checking the entire ODB subtree against all the variables represented in the 
string, I'm finding that only the first variable is checked.  The later variables in the string can be 
misspelled, out of order, or inexistent, and db_check_record() will still return 1.

Am I using db_check_record incorrectly?  

Thank you for any help with this issue.


I also believe that some of the documentation for db_check_record is outdated.  For example, init_string 
is referenced in the documentation but isn't part of the function definition.

Hi,

Attempting to copy a subtree to a new location in the ODB using odbedit with "copy <src> <dest>" is 
occasionally not copying the entire <src> subtree.

I am experiencing this issue consistently when trying to copy subtrees from the "/Equipment" ODB tree to 
a new location.  The first 2-3 variables/directories of the <src> subtree will be copied to <dest> but the 
full subtree will not be copied over.

Hello,

I am wondering if there is a function that checks the access mode for a key? I 
found the db_set_mode() function that allows me to set the access mode for a key, 
but failed to find its counterpart get function.

Thanks in advance,
Yan

Thank you!

Yan

> > Hello,
> > 
> > I am wondering if there is a function that checks the access mode for a key? I 
> > found the db_set_mode() function that allows me to set the access mode for a key, 
> > but failed to find its counterpart get function.
> > 
> > Thanks in advance,
> > Yan
> 
> 
>   KEY k;
>   db_get_key(hDB, handle, &k);
>   std::cout << k.access_mode << std::endl;
> 
> /Stefan

Dear MIDAS developers and colleagues,

    This is Yu CHEN of School of Physics, Sun Yat-sen University, China, working in the PandaX-III collaboration, an experiment under development to search the neutrinoless double 
beta decay. We are working on the DAQ and slow control systems and would like to use Midas framework to communicate with the custom hardware systems, generally via Ethernet 
interfaces. So currently we are focusing on the development of the FRONTEND program of Midas and have some questions and discussions on its ODB structure. Since I’m still not 
experienced in the framework, it would be precious that you can provide some suggestions on the topic.
    The current structure of the frontend ODB tree we have designed, together with our understanding on them, is as follows:
      /Equipment/<frontend_name>/
        ->  /Common/: Basic controls and left unchanged.
        ->  /Variables/: (ODB records with MODE_READ) Monitored values that are AUTOMATICALLY updated from the bank data within each packed event. It is done by the update_odb() 
function in mfe.cxx.
        ->  /Statistics/: (ODB records with MODE_WRITE) Default status values that are AUTOMATICALLY updated by the calling of db_send_changed_records() within the mfe.cxx.
        ->  /Settings/: All the user defined data can be located here. 
            -> /stat/: (ODB records with MODE_WRITE) All the monitored values as well as program internal status. The update operation is done simultaneously when 
db_send_changed_records() is called within the mfe.cxx.
            -> /set/: (ODB records with MODE_READ) All the “Control” data used to configure the custom program and custom hardware.

    For our application, some of the our detector equipment outputs small amount of status and monitored data together with the event data, so we currently choose not to use EQ_SLOW 
and 3-layer drivers for the readout. Our solution is to create two ODB sub-trees in the /Settings/ similar to what the device_driver does. However, this could introduce two 
troubles:
    1) For /Settings/stat/: To prevent the potential destroy on the hot-links of /Variables/ and /Statistics/ sub-trees, all our status and monitored data are stored separately in 
the /Settings/stat/ sub-tree. Another consideration is that some monitored data are not directly from the raw data, so packaging them into the Bank for later showing in /Variables/ 
could somehow lead to a complicated readout() function. However, this solution may be complicated for history loggings. I have find that the ANALYZER modules could provide some 
processes for writing to the /Variables/ sub-tree, so I would like to know whether an analyzer should be used in this case.
    2) For /Settings/set/: The “control” data (similar to the “demand” data in the EQ_SLOW equipment) are currently put in several /Settings/set/ sub-trees where each key in 
them is hot-linked to a pre-defined hardware configuration function. However, some control operations are not related to a certain ODB key or related to several ODB keys (e.g. 
configuration the Ethernet sockets), so the dispatcher function should be assigned to the whole sub-tree, which I think can slow the response speed of the software. What we are 
currently using is to setup a dedicated “control key”, and then the input of different value means different operations (e.g. 1 means socket opening, 2 means sending the UDP 
packets to the target hardware, et al.). This “control key” is also used to develop the buttons to be shown on the Status/Custom webpage. However, we would like to have your 
suggestions or better solutions on that, considering the stability and fast response of the control.

    We are not sure whether the above understanding and troubles on the Midas framework are correct or they are just due to our limits on the knowledge of the framework, so we 
really appreciate your knowledge and help for a better using on Midas. Thank you so much!

I am trying to start a program (fronend) from a custom page. What is the best
way to do that? Would ODBRpc() do this? if so can anyone give me an example of
how to do this. Thanks.

> > I am trying to start a program (fronend) from a custom page. What is the best
> > way to do that? Would ODBRpc() do this? if so can anyone give me an example of
> > how to do this. Thanks.
> 
> You have a look at the documentation:
> 
> http://ladd00.triumf.ca/~daqweb/doc/midas-old/html/RC_mhttpd_defining_script_buttons.html
> 
> Cheers,
> Stefan

Hi Stefan, thanks for the quick reply. I guess my question was not clear enough.

My aim is to create a button which mimics the "Start/Stop" button functionality in the
"Programs" page where we start all the front-ends for the various equipment. The idea is that
the user will use a simple interface in a custom page (not the status page) which sets up the
equipment needed for a specific type of measurement.

thanks
Zaher

Thank you very much, this is exactly what I need and it works.

Zaher

> All functions in midas are controlled through special URLs. So the URL
> 
> http://<host:port>/?cmd=Start&value=10
> 
> will start run #10. Similarly with ?cmd=Stop. Now all you need is to set up a custom button, and use the 
> OnClick="" JavaScript method to fire off an Ajax request with the above URL. 
> 
> To send an Ajax request, you can use the function XMLHttpRequestGeneric which ships as part of midas in the 
> mhttpd.js file. Then the code would be
> 
> <input type="button" onclick="start()">
> 
> and in your JavaScript code:
> 
> ...
> function start()
> {
>    var request = XMLHttpRequestGeneric();
> 
>    url = '?cmd=Start&value=10';
>    request.open('GET', url, false);
>    request.send(null);
> }
> ...
> 
> 
> Cheers,
> Stefan

Just in case anyone needs this in the future I am adding a comment about this issue. After a few months of working
with this solution we noticed that when using

request.open('GET', url, false);

on firefox it could cause the javascript to stop at that point, possibly due to a delayed response from the
server. A simple solution is to send an asynchronous requests

request.open('GET', url, true);

Zaher

> Thank you very much, this is exactly what I need and it works.
> 
> Zaher
> 
> > All functions in midas are controlled through special URLs. So the URL
> > 
> > http://<host:port>/?cmd=Start&value=10
> > 
> > will start run #10. Similarly with ?cmd=Stop. Now all you need is to set up a custom button, and use the 
> > OnClick="" JavaScript method to fire off an Ajax request with the above URL. 
> > 
> > To send an Ajax request, you can use the function XMLHttpRequestGeneric which ships as part of midas in the 
> > mhttpd.js file. Then the code would be
> > 
> > <input type="button" onclick="start()">
> > 
> > and in your JavaScript code:
> > 
> > ...
> > function start()
> > {
> >    var request = XMLHttpRequestGeneric();
> > 
> >    url = '?cmd=Start&value=10';
> >    request.open('GET', url, false);
> >    request.send(null);
> > }
> > ...
> > 
> > 
> > Cheers,
> > Stefan

I am embedding histories into a custom page within an SVG,

<image x="21000" y="1000" width="6000" height="6000"
href="../HS/SampleCryo/SampleTemp.gif?width=230&scale=0.5h"/>

this works fine. However, I would like to update this regularly without
refreshing the full page via

<meta http-equiv="Refresh" content="60">

is there a good way to do that? By the way, the "Periodic update of parts of a
custom page" from the documentation does not seem to work here.

I am getting the following error alert in a custom page whenever a run starts

json parser exception: SyntaxError: Unexpected token < in JSON at position 985, batch request: method: "db_get_values", params: [object Object], id: 1598691925697 method: "get_alarms", params: null, id: 1598691925697 method: "cm_msg_retrieve", params: [object Object], id: 1598691925697 method: "cm_msg_retrieve", params: [object Object], id: 1598691925697

Does anyone know why and what causes this? This does not affect anything and things seem to continue running fine.

thanks.

I have a history that is embedded in a custom page using

<div class="mjshistory" data-group="SampleCryo" data-panel="SampleTemp" data-scale="30m" style="'+size+' position: relative;left: 640px;top: -205px;"></div>

this works fine when I load the page but seems to cause a timeout when reloading (F5) the page. It used to work fine last year but since a midas update this year it does not work. 

When I manually stop the script when firefox reports that it is slowing down the browse I get the following in the console:

Script terminated by timeout at:
binarySearch@http://xxx.psi.ch:8081/mhistory.js:1051:11
MhistoryGraph.prototype.findMinMax@http://xxx.psi.ch:8081/mhistory.js:1583:28
MhistoryGraph.prototype.loadInitialData/<@http://xxx.psi.ch:8081/mhistory.js:780:15

any ideas what may be causing this?

thanks.

Another hint to the problem, the custom page is accessible via 
http://xxx.psi.ch:8081/?cmd=custom&page=SampleCryo&
once loaded the address changes to where A and B change values as time passes (I guess B-A=30m).
http://xxx.psi.ch:8081/?cmd=custom&page=SampleCryo&&A=1614173369&B=1614175169

Is it possible to embed modbvalue in an SVG for use within a custom page?

thanks.

I found a way to embed modbvalue into a SVG:

<text x="100" y="100" font-size="30rem">
Run=<tspan class="modbvalue" data-odb-path="/Runinfo/Run number"></tspan>
</text>

This seems to behave better that the suggestion below.

> You can't really embed it, but you can overlay it. You tag the SVG with a 
> "relative" position and then move the modbvalue with an "absolute" position over 
> it:
> 
> <svg style="position:relative" width="400" height="100">
>   <rect width="300" height="100" style="fill:rgb(255,0,0);stroke-width:3;stroke:rgb(0,0,0)" />
>   <div class="modbvalue" style="position:absolute;top:50px;left:50px" data-odb-path="/Runinfo/Run number"></div>
> </svg>

We had the same issue here, which comes from mhttpd.js line 2395 on the current git version. This seems to happen mostly when there is an alarm triggered or when there is an error message.

Anyway, the easiest solution for us was to define m at the beginning of mhttpd_message function 

let m;

and replace line 2395 with

if (m !== undefined) {


> > I see this mhttpd error starting MSL-script: 
> > Uncaught (in promise) ReferenceError: m is not defined
> > at mhttpd_message (VM2848 mhttpd.js:2304)
> > at VM2848 mhttpd.js:2122
> 
> your line numbers do not line up with my copy of mhttpd.js. what version of midas 
> do you run?
> 
> please give me the output of odbedit "ver" command (GIT revision, looks like this: 
> IT revision:       Wed Feb 3 11:47:02 2021 -0800 - midas-2020-08-a-84-g78d18b1c on 
> branch feature/midas-2020-12).
> 
> same info is in the midas "help" page (GIT revision).
> 
> to decipher the git revision string:
> 
> midas-2020-08-a-84-g78d18b1c means:
> is commit 78d18b1c
> which is 84 commits after git tag midas-2020-08-a
> 
> "on branch feature/midas-2020-12" confirms that I have the midas-2020-12 pre-
> release version without having to do all the decoding above.
> 
> if you also have "-dirty" it means you changed something in the source code 
>  and warranty is voided. (just joking! we can debug even modified midas source 
> code)
> 
> K.O.

It seems that a modbselect triggers a "change" in an ODB which has a hot link. This happens onload (or whenever the custom page is reloaded) and otherwise it behaves as expected, i.e. no change unless the modbselect is actually changed. Is this the intended behaviour? can this be modified?

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.