Re: [EXTERNAL] Gamma DIGITEL MPCq: mismatch after 0 bytes ""

[Abdalla Ahmad via Tech-talk <tech-talk at aps.anl.gov>]

Hi

Looking at the MPCq user manual, they look very similar to the QPC. We have the QPC models installed in many sub-systems of the facility, so we have a bit of experience.

• The Ethernet interface on older firmware versions behaves really strange; what happens is that when the IOC requests pressure ("cmd 0B 1" for example) the controller returns some other command response; current, voltage, status, etc. so, the GUI gets filled with INVALID severity. A quick solution is to either restart the IOC or disconnect and re-connect the port if you have the asynRecord.db loaded in the IOC to connect to the stream device port. But the best solution is to have the device's firmware always up to date. We believe this issue was resolved in later firmware versions (1.40+ maybe).
• I have experimented with the controller's Modbus TCP port, and I think it looks more stable than the Telnet port, not to mention a bit faster. However, I only tested pressure, voltage and current, I did not test channel status, setpoints, etc.

Here is our work with QPC both Ethernet and ModBus: https://github.com/SESAME-Synchrotron/epics-gamma 

Best Regards,

Abdalla.

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Baily, Scott A via Tech-talk <tech-talk at aps.anl.gov>
Sent: Thursday, July 9, 2026 4:46 AM
To: J. Lewis Muir <jlmuir at imca-cat.org>; EPICS Tech-Talk <tech-talk at aps.anl.gov>
Subject: Re: [EXTERNAL] Gamma DIGITEL MPCq: mismatch after 0 bytes ""

The issue is the prompt. I can think of several ways to handle this, I just changed the in termination to be /r/r/n>   The prompt is sent separately to technically it’s not part of the termination, but it is always sent after the response.

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of J. Lewis Muir via Tech-talk <tech-talk at aps.anl.gov>
Sent: Wednesday, 08 July 2026 17:22:18
To: EPICS Tech-Talk <tech-talk at aps.anl.gov>
Subject: [EXTERNAL] Gamma DIGITEL MPCq: mismatch after 0 bytes ""

 

Hi, Tech-Talkers!

I'm using the driver at

  https://urldefense.com/v3/__http://github.com/epics-modules/ip/blob/master/ipApp/Db/MPC_Ethernet.template__;!!Bt8fGhp8LhKGRg!BmWtxEb5lgCs6dhQy2XSk82mrXDHxsxPCPtxPTGc_8xz2T6kAUg6_qheSTOSsqA3Jj4VDCtPHtEwLHJkB2nHQg$

to control Gamma DIGITEL MPCq devices connected via Ethernet, and it
mostly works, but I sometimes get errors on the IOC console like the
following (it seems to happen for all of them, so not limited to just
one device), and I'm wondering, does anyone know what might be going
wrong and how to fix it?

----
2026/07/08 11:50:09.782653 GAMMA5 17ida:ip9:CUR: Input ">OK 00 1.1E-04 AMPS<0d><0d><0a>>..."
2026/07/08 11:50:09.782668 GAMMA5 17ida:ip9:CUR: mismatch after 0 bytes ""
2026/07/08 11:50:09.782674 GAMMA5 17ida:ip9:CUR: got ">OK 00 1.1..." where "OK 00 " was expected
----

This same pattern of errors occurs for various values (e.g., CUR,
GAUTOS, PRES, SIZE, VOLT, and STAT).

Thanks!

Lewis