EPICS RE: StreamDevice return state error

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You could try turning on debug messages in streamDevice, by adding this to the IOC shell:

var streamDebug 1

and also make sure error messages are turned on (but it seems like they are):

var streamError 1

And also printout all the record fields for RCV_STATE before and after the error:

dbpr RCV_STATE, 10

Surely RCV_STATE will be in error state, but the output from the above command will tell us one way or another.

I’m also not sure what the ‘out’ statement actually does in that protocol function. It might be trying to write the current state of STATE_RTN (ie. ‘OK’) back out to the device, which is probably not what you wanted?

Cheers,

Matt

From: Barrett (US), Patrick E <patrick.e.barrett at boeing.com>
Sent: Tuesday, June 28, 2022 1:22 PM
To: Pearson, Matthew <pearsonmr at ornl.gov>; tech-talk at aps.anl.gov
Subject: [EXTERNAL] RE: StreamDevice return state error

Sorry.. the message I get in the IOC with these suggested records is:

‘…RCV_STATE: Record does not accept input "MONITOR"’

From: Barrett (US), Patrick E <>
Sent: Tuesday, June 28, 2022 1:21 PM
To: 'pearsonmr at ornl.gov' <pearsonmr at ornl.gov>; 'tech-talk at aps.anl.gov' <tech-talk at aps.anl.gov>
Subject: RE: StreamDevice return state error

I tried this and get the same error. The Alarm state is not getting set in the record. It’s almost like the StreamDevice is handling/returning the error without putting the bad request into the record itself. Any other suggestions?

Thanks,

Patrick

From: Pearson, Matthew <pearsonmr at ornl.gov>
Sent: Tuesday, June 28, 2022 12:59 PM
To: Barrett (US), Patrick E <patrick.e.barrett at boeing.com>; tech-talk at aps.anl.gov
Subject: [EXTERNAL] RE: StreamDevice return state error

EXT email: be mindful of links/attachments.

Hi,

I’m assuming you mean that the STATE_RTN record should go to ERROR state if there’s a problem with the RCV_STATE record?

One way to do this is to use the STAT and/or SEVR fields of the RCV_STATE record. They should indicate a problem if either of those is !=0, and so you could do something like:

record(mbbi, "RCV_STATE")

{

field(DESC, "SYSTEM:STATE P01")

field(DTYP, "stream")

field(SCAN, "I/O Intr")

field(INP, "@simCmd.proto readSystemState(STATE_RTN) $(PORT) 0")

field(ZRST, "STANDBY")

field(ZRVL, "0")

field(ONST, "OPERATE")

field(ONVL, "1")

field(TWST, "SELFTEST")

field(TWVL, "2")

field(UNSV, "INVALID")

field(FLNK, “RCV_CALC”)

}

record(calcout, “RCV_CALC”)

{

field(INPA, “RCV_STATE.STAT”)

field(CALC, “A!=0?1:0”)

field(OOPT, “Every Time”)

field(DOPT, “Use CALC”)

field(OUT, “STATE_RTN PP”)

}

record(bi, "STATE_RTN")

{

field(DESC, "State Return")

field(DTYP, "Soft Channel")

field(SCAN, "Passive")

field(ZNAM, "OK")

field(ONAM, "ERROR")

field(VAL, 0)

field(PINI, 1)

}

Or, something along those lines.

Depending on which client you use, the RCV_STATE record itself should also indicate there’s a problem, and you can also display the STAT and/or SEVR fields if necessary.

Cheers,

Matt

From: Tech-talk <tech-talk-bounces at aps.anl.gov> On Behalf Of Barrett (US), Patrick E via Tech-talk
Sent: Tuesday, June 28, 2022 12:37 PM
To: tech-talk at aps.anl.gov
Subject: [EXTERNAL] StreamDevice return state error

I am working to simulate a SCPI type device with an IOC. I am using I/O Intr records to read in the SCPI and set the state of the mbbi record. The IOC should return ERROR if an error occurs, such as if an invalid state is requested. I can see the error message in the IOC when an invalid state is requested, but do not know how to capture the error in the protocol file or db setup to send a return string of “ERROR”.

The error I get is when sending the IOC “SYSTEM:STATE MONITOR” is: ’… RCV_STATE: Record does not accept input "MONITOR"’

Proto definition:

readSystemState

{

in "SYSTEM:STATE %s";

out "%(\$1)s";

}

Record definition: