IOC And Device Trouble Shooting

Wiki > Trouble-shooting > IOC and device trouble shooting

After diagnosing the problem If you needed to go down to the instrument please correct/update any connection information to Specific Device IOC page.

General tips

I am having an Issue with a Specific IOC

Some IOC have important details which may help see if it is listed in Specific Device IOC.

checking stream device/asyn serial port settings

At the IOC command prompt, type:

dbior("drvAsyn",2)

It doesn't work What Should I Do?

1. Connect over hyperterminal (see Connect over hyperterminal)
2. Check command set is correct (look at documentation)
3. Start the IOC and check it is not in SIM mode
4. Set the IOC mask (see What is Passing between the IOC and the Stream Device)
5. If you don't think records are processing correctly, try setting the TPRO (trace processing) field of the relevant records to a non-zero value. This will print a message to the IOC log whenever the record processes.

Connect over hyperterminal

Start hyper-terminal set up connection to device. Find a command that is returns something or that changes something on the display. Run that command look for the change. Try

1. Reading
2. Writing

If it doesn't work check:

1. Protocol (RS232, RS422, RS482)
2. Baud Rate
3. Com Port
4. Stop Bits
5. Parity
6. Line ending/Termination characters.
7. Flow control

If this doesn't work check the moxa logging (see data over the moxa connection). If this doesn't work there is a device that can be plugged into a serial port to intercept all traffic.

It won't work in the IOC initially, but with no changes works after connecting to hyperterminal

If the IOC doesn't work on startup, but does after using hyperterminal, at a command prompt run a mode com1 on the appropriate com port (example is for COM1) before and after running hyperterminal. If there is a change that isn't duplicated by starting the IOC, then there is possibly a setting missing in asyn.

It did work and then freezes

This may be due to a low control issue e.g. Xon/Xoff has been incorrectly specified and some binary character happens to match Xoff. You should see asyn still sending character when you enable trace, but non getting through. If you run the dbior command at level 2 you may see waiting as seen Xoff.

What is Passing between the IOC and the Stream Device

It is possible to put stream into a debug mode where everything sent and received is written to the console. To do this simply add to you st.cmd file (defined on your aysn port) :

asynSetTraceMask("L0",-1,0x9) 
asynSetTraceIOMask("L0",-1,0x2)

where is the port name you used in the asyn setup eg drvAsynSerialPortConfigure(<port>...

This will include the terminator character, if you don't see it it is not being sent or received. If no reply is given this will include a message "No reply from device in XXXms"

See ASYN-Trace-Masks for more details on specifying trace masks

Is the MOXA seeing anything?

It is sometime useful to see if the moxa is seeing any traffic. If you are in the cabin you can look at the flashing lights (remember to take away 4 to convert from com number to port number). There is one light for send and one for receive both should flash.

If you want to do it remotely then you can by using the moxa web page. The address is on the nagios page (standard log on). Look at Hosts -> MOXA_ the IP address is at top of the page in the middle. Enter the IP in a web browser and enter password from password page. Then Monitor -> Asyn shows received and sent byte count.

Environment Variable not getting set from MASTER_RELEASE

Varibles are transferred from ...EPICS\configure\MASTER_RELEASE to ...EPICS\ioc\master\<IOCNAME>\iocBoot\<IOCNAME>\envPaths when the ioc is made. You will have to delete the file to get the newest macros in and the paths have to exist.

I get a UDF alarm on by bi record that's getting its value from a calcout

This was observed whilst programming the GEMORC IOC. We had records like so:

record(calc, "$(P)CALC")
{
	field(INPA, "$(P)LONGIN1")
	field(INPB, "$(P)LONGIN2")
	field(CALC, "A+B==0")	
	field(OUT, "$(P)BI")
}

record(bi, "$(P)BI")
{
	field(ZNAM, "No")
	field(ONAM, "Yes")
}

The result was a UDF alarm on the bi because the RVAL wasn't being updated in line with the VAL. We tried a lot of things to sort this. In the end we changed the OUT field of the CALC to a FLNK and added the following field to the bi: field(INP, "$(P)CALC"). We don't know why this solution worked over the many others we tried.

IOC Crashes on debug the exception in "Unhandled exception at ... : Stack cookie instrumentation code detected a stack-based buffer overrun."

This is caused when something bad happens to the stack. There are many underlying causes to this, in my case it was that the IOC had loaded a dll which used an incorrect version of visual studio in its build. The dlls that are loaded (with their paths) can be seen in debug -> Windows -> Modules in VS. To check if it is this error delete the offending dll and try the process again. To fix the error convert the IOC to use build dependencies instead of the master release list, instructions are in Reducing Build Dependencies

Log shows currentTime::getCurrentTime(): XXX sec time discontinuity detected

The log for all IOCs shows the message:

currentTime::getCurrentTime(): XXX sec time discontinuity detected

It is caused by the time going backwards due to a correction; the underlying cause is unknown. However, this seems to disappear once the host machine is restarted.

Autosave

Lost autosave values (especially on Galils)

This is based on ticket: https://github.com/ISISComputingGroup/IBEX/issues/2180

Possible symptoms include:

• Autosaved values mysteriously changing when the IOC is restarted
  • This includes Galils not retaining their position
• Errors of the form `[DATE] dbFindRecord for 'MY_PV.FIELD' failed
• Autosave files containing just a header and <END> tag

This has been observed primarily on Galils since they create custom monitor sets but it is feasible the issue could be seen elsewhere. The Galils pass macros to their monitor sets. If no macros are passed (e.g. if GALILADDR0n is not set) then no monitor will be created and no values will be saved. This will mean the device (e.g. the motor) will start with its default values. If the macro is reintroduced then those default values will become the new autosave values. The previous values can be recovered by restoring a previous autosave file (e.g. copy GALIL_02_settings.sav_170309-144116 to GALIL_02_settings.sav and restart the IOC).

Motors

Limit switches not active at the limit position

https://github.com/ISISComputingGroup/IBEX/issues/2174

In the motor record (C:\Instrument\Apps\EPICS\support\motor\master\motorApp\MotorSrc\motorRecord.cc) the limit flag is only activated if the motor's limit switch bit is active and motor's command direction (CDIR) is correct. Correct in this context means that the motor is moving out of range. That is, the motor is moving in a positive direction past an upper limit or in a negative direction past the lower limit. The command direction is only set when a command (e.g. home, move) is sent. If the IOC is restarted, the value isn't saved (and cannot be auto saved) so the limit flag behaviour will depend on the initial value of the command direction.

In summary, being at the limit position is insufficient to cause the limit flag to be active. This is expected behaviour, though can be slightly unintuitive at first.

Readbacks from device keep twitching

This may be because of variances in the signal returned from the motor. This is true, for example, on the jaws set on Merlin. It also causes the motor status label on the bumpstrip to keep switching. Note that leaving it in this state can increase dramatically the amount of information sent to the archiver.

To fix, use caput for the relevant PV in the motor record:

IN:[INST]:MOT:MTR0n0m.MDEL: Sets the motor deadband. This will stop the position readback from oscillating IN:[INST]:MOT:MTR0n0m.ADEL: Sets the archiver deadband. This will stop values being written to the archiver unless the value changes by more than the deadband value IN:[INST]:MOT:MTR0n0m_EDEL_SP: Sets the encoder deadband. No readbacks will be updated unless the encoder varies by this amount.

McLennan OPI controls all red

• Does the panel on the front of the controller display a letter?
  • r
    • Can happen owing to a communication issue when the IOC starts if the baud rate/stop bits aren't set correctly
  • t
    • Tracking abort. Usually happens if the encoder resolution is incorrect. Is the ERES macro fraction the right way around?
  • n
    • Observed once on Merlin after the McLennan had been idle for a long time. Only happened after homing the motor. Restarting the controller (with the IOC stopped) fixed the issue
  • No
    • Try restarting the IOC, then move the motor through a significant operation (a home or jog to limit). Sometimes restarting the IOC is enough, sometimes the move causes the underlying issue to reveal itself (see n above)

Logging

I Changed the logging setting but it uses old settings

To sync up changes in logging from the DB file to the logging you must:

1. Restart the IOC so the logging info fields are pushed to the database
2. If any new PVs are being archived or settings have been changed the ARINST needs restarting
3. The ARACCESS needs restarting so it picks up the configuration changes from the database

There was an error which I have fixed but I missed a log file

To regenerate log files set the date in the c:\Logs\LOG_last_active_time to the time you want to start generating files from, if this is more than delta days ago (2nd line of the log file) increase this number too. Then restart the ARACCESS

I want to Generate a Log file from some PVs Now

This can be done between two dates see ...EPICS\ISIS\inst_servers\master\ArchiverAccess\log_file_generator.py as an example.

which process owns a serial port

From an administrator (i.e. gamekeeper) prompt, run the sysinternals handle command like:

handle.exe -a | findstr "Serial pid:"

This will print a list of PIDs and any matches to a serial port allocated, take the pid number above the relevant \Device\Serial line