Re: asyn trace masks on modbus reconnect

[Mark Rivers via Tech-talk <tech-talk@aps.anl.gov>]

Hi John,

> Am I correct in assuming that if this was because the IOC lost its connection to the plc, this would be reported as an error in the IOC console [asynTraceMask is not explicitly set so it is the default value of 1?]

Yes.  Starting in Modbus R2-17 (September 2017) each Modbus asyn port driver prints a single error message when a read operation from the PLC returns an error, and a single message when a read operation succeeds again.

Here is an example from when we were having some network issues recently:

[Tue Dec 21 12:06:01 2021] 2021/12/21 12:06:00.927 drvModbusAsyn::doModbusIO port K1_Yn_In_Bit error calling writeRead, error=164.54.160.197:502 read error: S_errno_EWOULDBLOCK, nwrite=6/6, nread=0

[Tue Dec 21 12:06:01 2021] 2021/12/21 12:06:01.027 drvModbusAsyn::doModbusIO port K1_Yn_In_Bit writeRead status back to normal having had 1 errors, nwrite=6/6, nread=6

Mark

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From: John Dobbins <john.dobbins@cornell.edu>
Sent: Thursday, March 31, 2022 7:54 PM
To: Mark Rivers <rivers@cars.uchicago.edu>; Mark Rivers via Tech-talk <tech-talk@aps.anl.gov>
Subject: Re: asyn trace masks on modbus reconnect

 

No documentation directory but if I look at modbusInterpose.c I see that it matches commits up to June 28,2019 which would make it 3-0 !

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From: Mark Rivers <rivers@cars.uchicago.edu>
Sent: Thursday, March 31, 2022 8:33 PM
To: Mark Rivers via Tech-talk <tech-talk@aps.anl.gov>
Cc: John Dobbins <john.dobbins@cornell.edu>
Subject: Re: asyn trace masks on modbus reconnect

 

If ii is older look in release notes in  documentation directory.

Sent from my iPhone

On Mar 31, 2022, at 7:24 PM, Mark Rivers via Tech-talk <tech-talk@aps.anl.gov> wrote:

 Look at the RELEASE.md in the top level directory.

Sent from my iPhone

On Mar 31, 2022, at 7:18 PM, John Dobbins <john.dobbins@cornell.edu> wrote:



Funny you should ask.  I am looking at this IOC built by someone else and modbus is installed with no obvious version label. Any easy well to tell?

John

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From: Mark Rivers <rivers@cars.uchicago.edu>
Sent: Thursday, March 31, 2022 8:11 PM
To: John Dobbins <john.dobbins@cornell.edu>
Cc: tech-talk@aps.anl.gov <tech-talk@aps.anl.gov>
Subject: Re: asyn trace masks on modbus reconnect

 

What version of the Modbus module?

Sent from my iPhone

On Mar 31, 2022, at 6:57 PM, John Dobbins via Tech-talk <tech-talk@aps.anl.gov> wrote:



All,

We have  a WAGO plc which we read via modbus. There are just 18 PVs in this IOC, read as two blocks from the plc. All the PVs briefly go invalid for ~ 5 seconds (as reported by clients like Alarm Server, Archive Appliance)

Am I correct in assuming that if this was because the IOC lost its connection to the plc, this would be reported as an error in the IOC console [asynTraceMask is not explicitly set so it is the default value of 1?]

Thanks,

John Dobbins

Research Support Specialist

Cornell High Energy Synchrotron Source

Cornell University

www.chess.cornell.edu