[Rich] [Dsg-rich] FPGA temp alarm

Tue Oct 16 13:52:00 EDT 2018

Chris, 

For the hardware interlocks, if any of the cRIO-based system's sensors (RTDs, humidity, airflow, air pressure, N2 flow; sensors not dependent on FPGA DAQ readout) go out of limit, the cRIO disables HV and LV by opening a relay contact to the Interlock port on the CAEN mainframe. 

This disables HV and LV and will only allow HV and LV to be re-enabled if the interlock is clear and a user has reset the interlock. 

Regards, 
Tyler 

From: "Chris Cuevas" <cuevas at jlab.org> 
To: "Valery Kubarovsky" <vpk at jlab.org>, "Mirazita Marco" <Marco.Mirazita at lnf.infn.it> 
Cc: rich at jlab.org, "dsg-rich" <dsg-rich at jlab.org> 
Sent: Tuesday, October 16, 2018 1:38:14 PM 
Subject: Re: [Rich] [Dsg-rich] FPGA temp alarm 

Hi All, 

The FPGAs have a firmware set point for the die temperature. Ben can verify this set point, but it sure sounds like the 'interlock' systems rely on software code. Are there watchdog timers set up in case the code stops running? 

For a true hardware interlock, one that does not depend on software, there should be temperature probes coupled directly to a comparator circuit which latches off the Low_Voltage outputs to the FPGA boards. From these email threads, it sounds like all the temperature devices are monitored with software, and if a software set point threshold is violated, then the Low_Voltage is turned OFF. If the monitored temperature devices go below the software set point threshold, is the Low_Voltage power reapplied automatically? 

Thanks, 

-Chris 

~~~~~~~~~~~~~~~~~ 
On 10/16/2018 9:40 AM, Valery Kubarovsky wrote: 

The detector (actually LV in this particular case, because the HV was off at that moment) 
was shut down by software interlock that monitors the FPGS temperature. 

BQ_BEGIN
From: "Marco Mirazita" <Marco.Mirazita at lnf.infn.it> 
To: "Tyler Lemon" <tlemon at jlab.org> 
Cc: "Valery Kubarovsky" <vpk at jlab.org> , rich at jlab.org , "dsg-rich" <dsg-rich at jlab.org> 
Sent: Tuesday, October 16, 2018 9:37:41 AM 
Subject: Re: [Rich] [Dsg-rich] FPGA temp alarm 

BQ_BEGIN
But we have a soft interlock shutting down the system if fpga 
temperature goes above 75 deg. 

Il 2018-10-16 14:24 Tyler Lemon ha scritto: 
> Hello Marco, 
> 
> The hardware interlock system does not monitor FPGA temperatures. It 
> monitors the RTDs installed in the EP. 
> 
> The hardware interlock system did not trip off the electronics because 
> the strange temperature readings were only seen on the FPGA 
> temperature readouts. 
> 
> Best regards, 
> Tyler 
> 
> ------------------------- 
> 
> FROM: "Mirazita Marco" <Marco.Mirazita at lnf.infn.it> 
> TO: "Valery Kubarovsky" <vpk at jlab.org> 
> CC: rich at jlab.org , "dsg-rich" <dsg-rich at jlab.org> 
> SENT: Tuesday, October 16, 2018 8:16:06 AM 
> SUBJECT: Re: [Rich] [Dsg-rich] FPGA temp alarm 
> 
> Hi Valery, 
> thank you, in fact my main worry was that the interlock didn't shut 
> down 
> the electronics. 
> It would be anyway good to understand why we had this event. 
> I saw from the strip charts that also the LV currents and voltages 
> have 
> frequent random spikes. 
> Marco 
> 
> Il 2018-10-16 13:55 Valery Kubarovsky ha scritto: 
>> Marco, 
>> If you take a more careful look you will find out that the LV was 
> shut 
>> down. 
>> The HV was off. We investigate the reason. It is the first time we 
> had 
>> such an event. 
>> Probably it was connected with the software update that was done 
>> approximately at the same time. 
>> Regards, 
>> Valery 
>> 
>> ------------------------- 
>> 
>>> FROM: "Marco Mirazita" <Marco.Mirazita at lnf.infn.it> 
>>> TO: dsg-rich at jlab.org , rich at jlab.org 
>>> SENT: Tuesday, October 16, 2018 4:03:24 AM 
>>> SUBJECT: [Dsg-rich] FPGA temp alarm 
>> 
>>> Hi all, 
>>> yesterday at about 4:20 pm jlab time I received several alarm 
>>> messages 
>>> saying that the FPGA temperatures reached values around 115 deg. 
>>> Since it looked like a readout error, I checked the strip chart, 
>>> where 
>>> there is actually a spike in the readout at that time, but to 
> values 
>>> of 
>>> the order of -10^5. See the attached plot. 
>>> So, it is clear that it was a readout error, but it is strange that 
>>> the 
>>> alarm message and epics report different values. 
>>> Also, according to the logbook, the electronics was not shut down 
> by 
>>> the 
>>> interlocks, as should have happened if the temperature really went 
>>> above 
>>> 100 deg. 
>>> So, perhaps the values reported in the alarm messages are not the 
>>> correct ones? 
>>> Marco 
>>> 
>>> _______________________________________________ 
>>> Dsg-rich mailing list 
>>> Dsg-rich at jlab.org 
>>> https://mailman.jlab.org/mailman/listinfo/dsg-rich 
>> 
>> _______________________________________________ 
>> Dsg-rich mailing list 
>> Dsg-rich at jlab.org 
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> https://mailman.jlab.org/mailman/listinfo/rich 

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