Experimental Physics and
Industrial Control System

Maren Purves via Tech-talk <tech-talk at aps.anl.gov> · Fri, 25 Mar 2022 12:31:55 -1000

That's not what I understand to be the intention, but setting the
value to 0 if the checksum is invalid, which should be relatively
simple if the modbus module separates the value from the checksum by
just setting the value to 0 depending on the value (or validity) of
the checksum in a calc record, or would that not work?

Maren Purves,
East Asian Observatory/JCMT

On Fri, Mar 25, 2022 at 3:58 AM Mark Rivers via Tech-talk
<tech-talk at aps.anl.gov> wrote:
>
> Do you mean that you are using the EPICS modbus module?  If so, it is not possible to ignore the checksum, if it is wrong it will always generate an error.  If the checksum is wrong then there is probably something wrong with your communications line or the device firmware and you should try to fix it.
>
> I believe that with StreamDevice you can just skip the checksum and it will not be an error.
>
> Mark
>
> ________________________________
> From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of 李姣赛 via Tech-talk <tech-talk at aps.anl.gov>
> Sent: Thursday, March 24, 2022 2:31 AM
> To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
> Subject: About checksum error
>
>
> Hi all,
>
>
> I found it would be parse the response first no matter the checksum is right or error, no matter StreamDevice or modbus. Is there a good way to ignore the response or parse the record value as 0 when there happens checksum error?
>
>
> Thanks in advance,
>
> Jiaosai Li

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System