Board, Interrupted

Came in at 3:00 pm on Tuesday to see how run was going, only to find it had stopped at some point.

Looking back at the transcript file (C:\SHARED\Server Code\node0.uart.trnscr), the run started at 5:14 pm, with a 250 mV threshold and 100 mV ladder steps.  (Note that DAC level 2 is unset.)

Mon Oct 03 17:14:32 2011 + 209 ms: < DAC_LEVELS,-0.250,-2.500,-0.350,-0.450,-0.550,-0.650

The end of the run, when the firmware hung, was 6:31 pm - around the time I left?

Mon Oct 03 18:31:19 2011 + 668 ms: < PULSE,1,30100,804013730552,1,(0,5)
Mon Oct 03 18:31:19 2011 + 669 ms: < PULSE,2,56923,804017705582,1,(0,4)
I'm wondering if something I did when I was leaving caused the run to halt.  Maybe I closed Eclipse while it was being used for STDOUT?

Anyway, let's try restarting.  I started a Quartus compile before I left, and it succeeded, so we can just reload everything from there.

BTW, I hooked the Peltier cooler to the ammeter function on the multimeter, and am getting readings like -0.450 A (-45 mA).  Actually, that was when the FPGA was in the crashed state; now that we're running again, the reading is decreasing (in its absolute value).  At this moment, it's -41.2 mA.

It makes sense that the reading is negative, because the device is passively responding to an outwards heat flow, so the bottom side of the plate is warmer than the top side.  To actively cool the system, we have to push current in the opposite direction from the way it flows naturally, so that the bottom side of the plate then becomes *cooler* than the top side.

Pulse rates for that 1-hour run were:

PMT#1:  30,100 pulses / 77 minutes = 390.1 ppm =   6.51 pps
PMT#2:  56,923 pulses / 77 minutes = 739.3 ppm = 12.32 pps

Stopped the current run, because Ray wants to replace the paddle assembly (scintillator + PMT) for SMA channel #1 (which is currently the one in Gun Case #2) with the third one to see if that improves things.