[dsg-hallb_rtpc] [EXTERNAL] Re: Pressure transducer of RTPC

[Marc Mcmullen]

Thanks Mohammad,

I'll look into the spares first. Then contact you about the repair.

Regards,
Marc
________________________________
From: dsg-hallb_rtpc <dsg-hallb_rtpc-bounces at jlab.org> on behalf of mhattawy at odu.edu <mohammad.hattawy at gmail.com>
Sent: Friday, July 24, 2020 11:16 AM
To: dsg-hallb_rtpc at jlab.org <dsg-hallb_rtpc at jlab.org>
Subject: Re: [dsg-hallb_rtpc] [EXTERNAL] Re: Pressure transducer of RTPC

Hello Marc,
    The magnets will be energized starting from 3:30 pm today to Monday morning. You won’t be able to get to the gas panel, that is within the fields of the magnets.


Mohammad

On Fri, Jul 24, 2020 at 11:11 Marc Mcmullen <mcmullen at jlab.org<mailto:mcmullen at jlab.org>> wrote:
Hi Jiwan,

I am going to see if we have some spare supplies for that chassis. When I have the swap out in  hand, I'll need to coordinate with your group to complete the repair.

The chassis will have to be de-energized and removed from the rack for repair. This means the MFC and the other connected sensors will have to be shut down while I make the repairs.

Additionally, I will be doing this work either on the weekend or after hours, to avoid coming into contact with others.

I'll let you know the status of the spares sometime today, so we can coordinate the system outage.

Regards,
Marc
________________________________
From: dsg-hallb_rtpc <dsg-hallb_rtpc-bounces at jlab.org<mailto:dsg-hallb_rtpc-bounces at jlab.org>> on behalf of Jiwan Poudel <jpoudel at jlab.org<mailto:jpoudel at jlab.org>>
Sent: Friday, July 24, 2020 9:33 AM
To: dsg-hallb_rtpc at jlab.org<mailto:dsg-hallb_rtpc at jlab.org> <dsg-hallb_rtpc at jlab.org<mailto:dsg-hallb_rtpc at jlab.org>>
Subject: Re: [dsg-hallb_rtpc] [EXTERNAL] Re: Pressure transducer of RTPC

Hello Brian,

Those power pins are not showing what it should show. Pin 6 and 5 showing -28.7V and pins 7 and 5 showing only 1.3V.

Thank you,
Jiwan

On Jul 23, 2020, at 2:29 PM, Brian Eng <beng at jlab.org<mailto:beng at jlab.org>> wrote:

Thanks Mohammad,

Fortunately it already has the pinout on it.

Unplug that connector and measure between pins 6 & 5 for -15 VDC, 7 & 5 for +15 VDC. If those are good then it isn't power.

Next open the backshell of that connector and connect probes to 2 & 12 to see if it is reading the same voltage as the cRIO (~4 VDC). If the reading at the sensor matches the cRIO it probably isn't the cabling.

Lastly I would disconnect the detector and open the valves so that sensor is exposed to ambient pressure and see what it reads, if it's still ~400 torr then it is most likely the sensor, but could be the cabling/chassis.

To eliminate that possibility the sensor would need to be removed and tested on a bench using the same pins as listed above.

I don't think we (DSG) have a direct replacement for that, so I'd try Hall B and if not you'd need to talk with Bob as that involves changing a pressure system component.

________________________________
From: dsg-hallb_rtpc <dsg-hallb_rtpc-bounces at jlab.org<mailto:dsg-hallb_rtpc-bounces at jlab.org>> on behalf of mhattawy at odu.edu<mailto:mhattawy at odu.edu> <mohammad.hattawy at gmail.com<mailto:mohammad.hattawy at gmail.com>>
Sent: Thursday, July 23, 2020 1:21 PM
To: dsg-hallb_rtpc at jlab.org<mailto:dsg-hallb_rtpc at jlab.org> <dsg-hallb_rtpc at jlab.org<mailto:dsg-hallb_rtpc at jlab.org>>
Subject: [dsg-hallb_rtpc] [EXTERNAL] Re: Pressure transducer of RTPC

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On Thu, Jul 23, 2020 at 12:38 Brian Eng <beng at jlab.org<mailto:beng at jlab.org>> wrote:
Hi Jiwan,

The voltage being read back by the cRIO is ~4V which is being converted correctly to ~400 torr.

Can you get the full model number of PT334 so I can better give some suggestions on what you guys could measure to help troubleshoot?

Off-hand some of the things that could be wrong is: the sensor not getting proper supply voltage, a loose connection of the output to the cRIO as it is getting some voltage back, or a bad sensor (let's hope it isn't that as that was the only one we had in that range).

________________________________
From: Jiwan Poudel <jpoudel at jlab.org<mailto:jpoudel at jlab.org>>
Sent: Thursday, July 23, 2020 11:20 AM
To: Brian Eng <beng at jlab.org<mailto:beng at jlab.org>>
Cc: dsg-hallb_rtpc at jlab.org<mailto:dsg-hallb_rtpc at jlab.org> <dsg-hallb_rtpc at jlab.org<mailto:dsg-hallb_rtpc at jlab.org>>
Subject: Pressure transducer of RTPC

Hello Brian,

RTPC abs. Pressure transducer seems not working properly. This should show around 760 torr (~ 1 atm), but showing about 400 torr only. What could be the reason?

Thank you,
Jiwan

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Best regards,
Mohammad Hattawy.
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