[Hallb-engineering] Fwd: Hall B - Instrumentation on magnets

[Dave Kashy]

----- Forwarded Message -----
From: "Ruben Fair" <rfair at jlab.org>
To: "Robert Miller" <rmiller at jlab.org>, "Volker Burkert" <burkert at jlab.org>, "Stepan Stepanyan" <stepanya at jlab.org>, "Eugene Pasyuk" <pasyuk at jlab.org>, "Doug Tilles" <tilles at jlab.org>, "Denny Insley" <dinsley at jlab.org>
Cc: "Probir Ghoshal" <ghoshal at jlab.org>, "kashy" <kashy at jlab.org>, "Renuka Rajput-Ghoshal" <renuka at jlab.org>, "Scot Spiegel" <spiegel at jlab.org>, "Nick Sandoval" <sandoval at jlab.org>, "Pablo Campero Rojas" <campero at jlab.org>, "Wesley Moore" <wmoore at jlab.org>, "Brian Eng" <beng at jlab.org>, "Krister Bruhwel" <bruhwel at jlab.org>, "George Biallas" <biallas at jlab.org>
Sent: Friday, November 10, 2017 12:41:22 PM
Subject: Hall B - Instrumentation on magnets

Good afternoon, 

It has been brought to my attention that a hall sensor was removed from the Hall B Solenoid to make room for a detector. 

That in itself is not a huge issue as obviously the detector needed to be installed. 

However, we were not informed of this sensor removal and the first indication that we had an issue was when we were running the Solenoid on Wednesday evening. 

Now, as it turns out the hall sensor is not part of any critical magnet operational procedure so the magnet and its sub-systems were not in any danger of being damaged. 

However, we spent time (on Wednesday evening and again yesterday and today) trying to troubleshoot this issue and had to carry out some temporary wiring modifications within the instrumentation racks. In fact we will have to do a bit more re-wiring to make this change permanent. 

We will now also have to modify the PLC code and magnet power supply EPICS control screen as the individual hall sensor readings are used to calculate and display the central field. 

In the future, please DO NOT remove or alter any instrumentation or controls on either of the magnets without consulting with me first or at the very least inform me at the earliest opportunity if you have made any changes. 

Please note that this request also applies to any changes to the immediate environment of the magnets - e.g. placing ferromagnetic material in close proximity to the magnet. 

As I am sure you will appreciate we cannot afford to have any delays in starting up and running our Physics experiments. In this instance, no delays occurred but it could have been worse if something else had been affected. 

Please pass this note on to any other Hall B staff as necessary. 

Regards 

Ruben