[Dsg-halla_ecal] emergency shutdown for ECal

[Marc Mcmullen]

Using an AC relay on the 120V is an option.

 However, The supply also has a 5V sense circuit that we are going to test. Essentially, removal of the 5V would disable output from the supply. But again, we have to test this with the controls before we can definitely say the best way. We will certainly rope in electrical safety on any plans.

I’ll look at my schedule and let you know when I’m available to meet.

Marc

________________________________
From: Donald Jones <jonesdc at jlab.org>
Sent: Wednesday, July 5, 2023 7:54:59 AM
To: Marc Mcmullen <mcmullen at jlab.org>
Cc: dsg-halla_ecal at jlab.org <dsg-halla_ecal at jlab.org>
Subject: Re: emergency shutdown for ECal

Thanks, Marc. Is there a time you could meet me in Physics Storage at the test setup? I am reconfiguring things and want to make sure the RTDs end up in the correct places.
We should put the controls system on high priority. I was told that we have to have a complete electrical design approved by Electrical Safety before they will provide approval to even start building ECal which was supposed to be well underway by now. Also, I don't believe the remote shutoff is sufficiently robust to pass safety muster. It will work great for controls though. It's rather weird because the default state is on (switch open) and off (switch closed). Perhaps you could change the default using a relay whose default was closed? However, as a part of the safety shutdown system without an obvious physical switch being turned off, I don't think Electrical Safety will approve. Perhaps a set of relays similar to the ones you are currently using to switch power on and off at the AC mains level would be more appropriate. Anyway, I'll stop thinking out loud, but it might be a good idea to pull Rick Adrover in to this conversation to avoid wasting time on something he won't approve.
-Don

Donald Jones
Hall A/C Staff Scientist
Jefferson Lab
Newport News, VA
________________________________
From: Marc Mcmullen <mcmullen at jlab.org>
Sent: Wednesday, July 5, 2023 6:39 AM
To: Donald Jones <jonesdc at jlab.org>
Cc: dsg-halla_ecal at jlab.org <dsg-halla_ecal at jlab.org>
Subject: Re: emergency shutdown for ECal

Hi Don,

Brian and I are looking into the controls safety for the overall detector. Currently, on the 6 supermodule test stand we are using an Omega reading a single RTD at the top of the detector to remove power to the heaters.

The new LED drivers (adjustable power supplies) have a built-in remote shutoff. We are looking into using that circuit to remove output power from the supply.

I will set a meeting sometime this month and we can discuss the overall controls safety.

Marc
________________________________
From: Donald Jones <jonesdc at jlab.org>
Sent: Monday, July 3, 2023 3:58 PM
To: Marc Mcmullen <mcmullen at jlab.org>
Cc: dsg-halla_ecal at jlab.org <dsg-halla_ecal at jlab.org>
Subject: emergency shutdown for ECal

Hi Marc,
I am trying to think through how we (you) will be able to implement the over-temperature shutdown on the ECal heater system. I think you said that the LED driver supplies, replace the relays. My understanding was that you were planning to use an Omega process controller to shut off the relays in the event of an over-temp condition. Did I understand correctly and do we need to re-introduce them? Here is the layout of the electrical system as planned which has no emergency shutoff relay. We could in principle, connect the 120 VAC plugs into relays that are powered by the AC mains.
-Don
[cid:2f54876a-4459-4239-85da-b81d4eb44dce]
-Don

Donald Jones
Hall A/C Staff Scientist
Jefferson Lab
Newport News, VA
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