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LET: Mezei Neutron Spin Flipper #3738

Closed Kevin-Woods-Tessella closed 5 years ago

Kevin-Woods-Tessella commented 5 years ago

As a LET scientist, I want to control the Mezei Neutron Spin Flipper, so that I can perform experiments with polarised neutrons.

The Mezei Neutron Spin Flipper is a collection of devices (power supplies, signal generators & control PC) housed in a mobile rack. The control PC runs a Python script to control the power supplies & signal generators. The Python script accepts a set of simple commands. SECI provides a simple GUI which sends the appropriate commands to the Python script. All IBEX needs to do is replicate the functionality of the existing SECI GUI (VI), sending the appropriate commands to the Python script running on the control PC (housed in the mobile rack).

The Mezei Neutron Spin Flipper is currently used on LET and POLREF, although it could be used on other instruments, if required.

Acceptance Criteria

  1. I can control the Mezei Neutron Spin Flipper from the IBEX GUI
  2. I can control the Mezei Neutron Spin Flipper from genie_python
  3. I can control more than one Mezei Neutron Spin Flipper from either IBEX GUI or genie_python.
  4. Solution to be ready for mid-Cycle 2018/04 (experiment is scheduled for 13th March).

Notes

  1. The Mezei Neutron Spin Flipper will be used in Cycle 2018/04.
  2. For details see the LET Wiki page.
  3. There is an existing VI to control the Mezei Neutron Spin Flipper, located here: C:\LabVIEW Modules\Instruments\POLREF\POLREF Flipper. Consult with Goran Nilsson or Andrew Caruana for more details.
  4. See also the notes provided by Tom & Gareth below.
  5. For the avoidance of doubt: any mention of He3 in relation to this ticket is a red-herring (caused by an initial misunderstanding of which equipment was to be used).
Tom-Willemsen commented 5 years ago

Talk with Christy and Andrew (Polref) as well as LET.

Summary of what was discussed in sprint backlog pruning:

There was a question raised about whether this is the best approach. An alternative solution under IBEX would be to run this new IOC directly on the separate PC, cutting out the intermediate TCP connection.

Confirm how many flippers they are using (1 or 2). It may be possible to run multiple flippers at the same time. Note (added 31/01/2019): There will be occasions when scientists want to run 2 flippers.

Kevin-Woods-Tessella commented 5 years ago

@Tom-Willemsen - is the He3 flipper on LET the same as the one on POLREF (i.e. is it the same device or the same design (if there is more than one He3 flipper))? Note (added 31/01/2019): The Flipper used on LET & POLREF is a Mezei Neutron Spin Flipper. There is a He3 Flipper, but it is a different beast.

John-Holt-Tessella commented 5 years ago

Ask Rob H who is responsible for this code? Note (added 31/01/2019): The scientists are responsible for the Python code that runs on the flipper control PC.

GDH-ISIS commented 5 years ago

The original development for this equipment came from Goran Nilsen on LET. Written with LabVIEW server and client. Used a Daq card with dual output and located on a seperate PC and four Genesys power supplies. This was then subsequently developed on the server side using a Python script by a PC under the supervision of Goran.

Subsequently, POLREF has adopted a similar system, but the system has been further developed. POLREF instrument scientist Andrew Caruana has further developed the python code, and the SECI LabVIEW client has been updated to cater for this. A version of this LabVIEW client has been put on LET.

To cut a long story short, before this work is undertaken, I think it would be worth talking to Goran Nilsen with the POLREF and LET instrument scientists for clarification of everything - there is certainly some common development here, although LET may be a single flipper, POLREF a dual Flipper.

Please note : this equipment is still going through development on POLREF. I am less certain of circumstances on LET. That said, the server client relationship has been via simple TCP protocol for both systems.

kjwoodsISIS commented 5 years ago

Update information from David Voneshen: He3 spin flipper is not likely to be needed until mid-March. I will push this ticket down the priority list.

From: Voneshen, David (STFC,RAL,ISIS) Sent: 08 January 2019 15:16 To: Woods, Kevin (Tessella,RAL,ISIS); Bewley, Robert (STFC,RAL,ISIS) Cc: Howells, Gareth (STFC,RAL,ISIS) Subject: RE: LET: He3 Spin Flipper

Hi Kevin,

Yes, we haven’t scheduled from 1st March yet but there will likely be an experiment starting on the 13th of March which will need this (I wont be able to confirm for another week or so but I am 95% sure it will be here).

If you need any more details on this I would suggest speaking to Gøran Nilsen about this as it is really his equipment.

Tom-Willemsen commented 5 years ago

Andrew has given us the code used on the remote machine as a reference point, it is located here: \\isis\shares\ISIS_Experimental_Controls\external_code\Mezei Neutron Spin Flipper

Tom-Willemsen commented 5 years ago

PRs: