RE: problems with SNL - sevr=minor ca_array_get_callback [...]: Virtual circuit disconnect

[Žiga Oven via Tech-talk <tech-talk at aps.anl.gov>]

Hi Dariush,

I would check is if the IOC that runs the sequencer has access to the PVs in the other (I assume motor) IOCs.

If you issue the command "seqcar 2" on the IOC that runs the sequencer, this should report the status of the sequencer's access to the PVs.

Sequencer does provide you option to force all PVs to be connected before it starts the program execution, by using the "+c" option during the compile time
https://urldefense.us/v3/__https://epics-modules.github.io/sequencer/Compiling.html?highlight=options*compiler-options__;Iw!!G_uCfscf7eWS!ZQOxUIoply6dshIym9TbEVSS6qzdC0jHp5f70zAY5ST32f5zez2Pi50LcoCP5lxEisEbxkRH_BK_QreD2MhNv8iv$ 

Best regards,

Žiga


> -----Original Message-----
> From: Tech-talk <tech-talk-bounces at aps.anl.gov> On Behalf Of Dariush Hampai
> via Tech-talk
> Sent: Thursday, January 8, 2026 10:20
> To: tech-talk at aps.anl.gov
> Subject: problems with SNL - sevr=minor ca_array_get_callback [...]: Virtual
> circuit disconnect
> 
> Caution: This email originated from outside of Cosylab.
> 
> 
> Dear Community,
> Dear Mark and Maurizio,
> 
> I'll try to explain my error from which I'm not able to resolve.
> I developped a SNL sequencer ablo to make a raster scan with 20 motors (but
> scalable to how many motors needed) and 20 detectors (same as motors
> number...).
> In the link you can find the code (up to now I only use "xena_snscan.stt", as the
> other ones will be the same)
> https://urldefense.us/v3/__https://github.com/Teclis77/Scan-
> Program__;!!G_uCfscf7eWS!aPQyj4WdR7O49u2p_NU4H2lPpTDgz2o1XaIePmA
> WaJUE8f9HK3CQHpkDwIJWzSP9xdgUviafCfyswv0QGFHqZ1y-Th_61Np0-g$
> 
> To test the scan I use procServ in order to start contemporary 3 different IOCs
> (mm4006 for motors, ortec for detector and the scan). Up to here all is ok.
> Using telnet I can monitor the scan IOC and after populate the
> 1) number of motors;
> 2) number of detectors;
> 3) name of motor IOCs involved in the scan;
> 4) name of detector IOCs involved in the scan;
> 5) start position for each motor;
> 6) end position for each motor;
> 7) step position for each motor
> I prepare the the loop using difdferent status_mode value (1 for populate
> motor variables in stt file, 2 for detector variables, 3 for defing the loop
> parameters) When I initialize the scan (status_mode=4), I have a strange error.
> Knowing that the variables (for motor_ma, but for the other are the same
> procedures) are built (in xena_sncscan.stt) as
> 
> ***
> sprintf(temp_string, "%s:%s", motor[i], setma); printf("%s\n", temp_string);
> pvAssign(motor_ma[i],temp_string);
> sprintf(temp_string, "%s:%s", motor[i], reqmoving); printf("%s\n",
> temp_string); pvAssign(motor_reqmov[i],temp_string);
> sprintf(temp_string, "%s:%s", motor[i], moving); printf("%s\n", temp_string);
> pvAssign(motor_mov[i],temp_string);
> sprintf(temp_string, "%s:%s", motor[i], pos); printf("%s\n", temp_string);
> pvAssign(motor_pos[i],temp_string);
> ***
> 
> with the output correct form "mm4006_1_1_1:setma",
> "mm4006_1_1_1:reqmoving", "mm4006_1_1_1:moving" and
> "mm4006_1_1_1:pos"
> (these strings work right with caput command in other cmd so they are ok)
> 
> and the status_mode=4 is the following
> /*=================== Preparing Scan =========================*/
> /*=================== status_mode = 4 ========================*/
>          state prepare_loop {
>                  when () {
>                          for (i = 0; i < num_mot; i++) {
>                                  printf("motor to move = %d\n", i);
>                                  printf("start[%d]= %f\n", i, start[i]);
>                                  motor_ma[i]=start[i];
>                                  pvPut(motor_ma[i],SYNC);
>                                  motor_reqmov[i]=1;
>                                  pvPut(motor_reqmov[i],SYNC);
>                                  pvGet(motor_mov[i],SYNC);
>                                  while(motor_mov[i]<1) {
>                                          motor_reqmov[i]=1; pvPut(motor_reqmov[i],SYNC);
>                                          pvGet(motor_mov[i],SYNC);
>                                  }
>                                  pvGet(motor_pos[i], SYNC);
>                          }
>                          flags[0]=1; // Necessary to start the run
>                          strcpy(actual_status, "Ready to Start");
>                          pvPut(actual_status,SYNC);
>                          status_mode=0;
>                          pvPut(status_mode);
>                  } state dummy_loop
>          }
> 
> in the "telnet" prompt I have the following exit sevr=minor
> ca_array_get_callback( typeToCA(type), count, var->chid, pvCaGetHandler, arg):
> Virtual circuit disconnect
> 
> coming from:
> pvPut(motor_ma[i],SYNC);
> 
> using seqChanShow xena_sncscan I obtain
> 
> #9 of 263:
>    Variable name: "start"
>      type = double
>      count = 20
>    Value = 1000 1500 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
>    Assigned to "xena:start"
>    Connected
>    Monitored
>    Not sync'ed
>    Status = 0
>    Severity = 0
>    Message =
>    Time stamp = 2026-01-08 17:26:57.769209 Next? (+/- skip count)
> 
> and
> 
> #43 of 263:
>    Variable name: "motor_ma[0]"
>      type = double
>      count = 1
>    Value = 1000
>    Assigned to "mm4006_1_1_1:setma"
>    Not connected
>    Monitored
>    Not sync'ed
>    Status = -2
>    Severity = -1
>    Message = disconnected
>    Time stamp = <undefined>
> Next? (+/- skip count)
> 
> what I'm wrong?
> awaiting your replies...
> 
> Dariush
> 
> --
> ************************************
> 
> Dr. Dariush Hampai, PhD
> 
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