[Dsg-hallb_magnets] [New Logentry] Follow-up Re: Polarity Change PLC Logic

[beng at jlab.org]

Logentry Text:
--
<p>The polarity change code was slightly modified on <strong>only</strong> the solenoid PLC to allow for changing of the setpoint after a trip. As was found during the controlled ramp on 1/23 the code prevents stopping the ramp down until it is completed.</p><p>A snippet of previous code to compare new and previous setpoint polarity was as follows:</p><blockquote><p>(MPS.I_fromHMI > 0) XOR (Last_I > 0)</p></blockquote><p>This has been changed to the following:</p><blockquote><p>(MPS.I_fromHMI > 0) XOR (MPS.I_fromMPS > 0)</p></blockquote><p>The issue with the previous code was that during a controlled ramp Last_I would get set to zero, which is neither positive or negative.</p><p>So in lieu of using the previous setpoint the current from the MPS is used.</p><p>See attached image of a controlled ramp being stopped. As the solenoid MPS no longer physically has a polarity switch installed this change should be safe despite less than rigourous testing.</p>

---

This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/4245989
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.jlab.org/pipermail/dsg-hallb_magnets/attachments/20240131/8b0bd1b4/attachment.html>