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Ok. My understanding is that there is a remote control input which operates like a switch with open=On and closed=Off which is opposite what we would normally think of, but which allows the unit to operate normally with this input completely disconnected and
unused. There is also a 5Vsb input that puts the supply into standby mode when 5V@0.5A is input. Multiply that by 43 zones and that's 21.5A of current on the input just to keep it in standby. Correct me if I misunderstand the documentation (attached). Furthermore,
both of these control circuits (remote control and standby), go through black box processing/detection circuits. How much of a neutron dose before you lose that control and the heater is stuck on? We don't know, although we will have a better idea after our
prototype in-beam test this Fall. Given that these controls are governed by unknown circuitry, I am recommending not using them for emergency controls. Ideally, we should have a standalone controller not linked in any way to our temperature control system
and certainly not dependent on the LabVIEW GUI that simply shuts down the whole system if the temperature gets too high on any one of an array of thermocouples.</div>
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-Don</div>
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Donald Jones</div>
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Hall A/C Staff Scientist</div>
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Jefferson Lab</div>
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Newport News, VA</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Marc Mcmullen <mcmullen@jlab.org><br>
<b>Sent:</b> Wednesday, July 5, 2023 8:31 AM<br>
<b>To:</b> Donald Jones <jonesdc@jlab.org><br>
<b>Cc:</b> dsg-halla_ecal@jlab.org <dsg-halla_ecal@jlab.org><br>
<b>Subject:</b> Re: emergency shutdown for ECal</font>
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<div dir="ltr">Using an AC relay on the 120V is an option.</div>
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<div dir="ltr"> 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. </div>
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<div dir="ltr">I’ll look at my schedule and let you know when I’m available to meet. </div>
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<div dir="ltr">Marc</div>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Donald Jones <jonesdc@jlab.org><br>
<b>Sent:</b> Wednesday, July 5, 2023 7:54:59 AM<br>
<b>To:</b> Marc Mcmullen <mcmullen@jlab.org><br>
<b>Cc:</b> dsg-halla_ecal@jlab.org <dsg-halla_ecal@jlab.org><br>
<b>Subject:</b> Re: emergency shutdown for ECal</font>
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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.</div>
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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 <u>start</u> 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.</div>
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-Don</div>
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Donald Jones</div>
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Hall A/C Staff Scientist</div>
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Jefferson Lab</div>
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<div id="x_x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Marc Mcmullen <mcmullen@jlab.org><br>
<b>Sent:</b> Wednesday, July 5, 2023 6:39 AM<br>
<b>To:</b> Donald Jones <jonesdc@jlab.org><br>
<b>Cc:</b> dsg-halla_ecal@jlab.org <dsg-halla_ecal@jlab.org><br>
<b>Subject:</b> Re: emergency shutdown for ECal</font>
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Hi Don,</div>
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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.</div>
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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.</div>
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I will set a meeting sometime this month and we can discuss the overall controls safety.</div>
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Marc<br>
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<div id="x_x_x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Donald Jones <jonesdc@jlab.org><br>
<b>Sent:</b> Monday, July 3, 2023 3:58 PM<br>
<b>To:</b> Marc Mcmullen <mcmullen@jlab.org><br>
<b>Cc:</b> dsg-halla_ecal@jlab.org <dsg-halla_ecal@jlab.org><br>
<b>Subject:</b> emergency shutdown for ECal</font>
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Hi Marc,</div>
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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.</div>
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-Don</div>
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<img class="x_x_x_x_ContentPasted0 x_x_x_x_w-1882 x_x_x_x_h-1058" size="393477" style="max-width:100%" data-outlook-trace="F:4|T:4" src="cid:2f54876a-4459-4239-85da-b81d4eb44dce"><br>
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-Don</div>
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Donald Jones</div>
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Jefferson Lab</div>
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