[Halld-controls] PXI Time Stamps

[Hovanes Egiyan]

Brian, are you going to change the firmware on a PLC module? I did not 
quite

understand what is going to be upgraded and rebooted.

Hovanes.


On 09/04/2018 09:42 AM, Beni Zihlmann wrote:
> I think yes we should do this.
>
> On 09/04/2018 09:36 AM, Timothy Whitlatch wrote:
>> Hi Brian,
>>
>> We will have time this week to reboot the PXI (Just not today).
>>
>> Hovanes and Beni, do you think we should implement the fix this week?
>>
>>
>> Tim Whitlatch
>> Hall D Engineer
>> Jefferson Lab
>> 600 KELVIN DR STE 5
>> Newport News, VA 23606-4468
>> 757-269-5087
>>
>> ------------------------------------------------------------------------
>> *From: *"Brian Eng" <beng at jlab.org>
>> *To: *"Hall D Controls" <halld-controls at jlab.org>
>> *Sent: *Thursday, August 30, 2018 1:46:47 PM
>> *Subject: *[Halld-controls] PXI Time Stamps
>>
>> We recently discovered that the time used by the PLCs has a offset to 
>> it which causes them to use/provide an incorrect time.
>>
>> It manifests itself in 2 ways:
>> 1) If the CC server is the master the PLC will be 34 seconds fast
>> 2) if the PLC is the master any devices on the same subnet will be 34 
>> seconds fast
>>
>> That 34 seconds is hard-coded in the PLC ethernet module and only 
>> changed by upgrading the firmware (but it still won't be user 
>> adjustable). It comes from the offset between UTC & TAI time when the 
>> module was purchased.
>>
>> Currently we're operating in the second configuration.
>>
>> There is an option to correct this offset with Linux based NI 
>> devices, but I haven't yet tested it with the other OSes (namely the 
>> PXI which uses Phar Lap).
>>
>> Unfortunately even if I can remove this offset it will require 
>> rebooting the PXI, so my question is should I try pursuing fixing 
>> this or is knowing that there is a fixed & constant offset good 
>> enough for now?
>>
>>
>>
>>
>> P.S. This isn't like the earlier time problems we had where the time 
>> would slowly wander off, this is a fixed value with only the error of 
>> PTP coming into play which should be at the sub-ms level.
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>>
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>
>
>
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