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
From: John Dobbins <john.dobbins at cornell.edu>
Sent: Thursday, March 31, 2022 7:54 PM
To: Mark Rivers <rivers at cars.uchicago.edu>; Mark Rivers via Tech-talk <tech-talk at 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 !
From: Mark Rivers <rivers at cars.uchicago.edu>
Sent: Thursday, March 31, 2022 8:33 PM
To: Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>
Cc: John Dobbins <john.dobbins at 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 at 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 at 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
From: Mark Rivers <rivers at cars.uchicago.edu>
Sent: Thursday, March 31, 2022 8:11 PM
To: John Dobbins <john.dobbins at cornell.edu>
Cc: tech-talk at aps.anl.gov <tech-talk at 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 at 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
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