Experimental Physics and
Industrial Control System

Ralph Lange <[email protected]> · Wed, 15 Feb 2012 16:58:02 +0100

Hi Mark,

I only have the choice between Modbus serial/RTU and weird serial/ASCII.

Stream does handle byte order and checksums reasonably, that was
actually a minor issue, e.g.
   # Read word parameter         $1 = address, $2 = parameter (word) no.
   rdWord  { out $1 3 0 $2 0 1 "%#<crc16>"; in $1 3 2 "%0.2r%#<crc16>" }
That didn't look too bad.

Right now the device does not answer any of the two modes though ....
maybe I have things to fix on the physical layer first.

Thanks,
~Ralph

On 15.02.2012 15:16, Mark Rivers wrote:
> Hi Ralph,
>
> Is it serial/ASCII or serial RTU?
>
> It seems difficult to do Modbus with Stream.  Your protocol would have to worry about byte order, CRC, etc.
>
> Mark
>
> ________________________________________
> From: [email protected] [[email protected]] on behalf of Ralph Lange [[email protected]]
> Sent: Wednesday, February 15, 2012 3:44 AM
> To: EPICS Tech Talk
> Subject: Modbus/serial using Stream?
>
> Hi,
>
> has anyone ever tried to talk to a Modbus server (Modbus/serial) using
> Stream device?
> I am trying to get my unresponsive units to answer me, and looking at a
> working Modbus protocol file would really really help me.
>
> I know there is Mark's modbus driver, but I was more comfortable adding
> another protocol file instead of adding another software package.
> Until now, maybe?!
>
> Thanks a lot,
> ~Ralph
>

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System