Wed., Dec. 14th

The ECE department approved a $750 budget for students to buy needed parts & materials for the project.  I spoke to Donna to confirm that this was FSU money, and emailed the students that they could begin contacting her to process purchases and reimbursements.

Sonja emailed me that the Tektronix cables have arrived.  This will let us finish putting together the 3rd (and last, for now) detector apparatus.  I will get it this afternoon (and turn in my timesheet and sign my Spring paperwork at the same time).

Whenever Ray is ready, we can try removing that unwanted surface-mount capacitor from the FEDM board using the techniques we reviewed yesterday on YouTube.  This will then allow us to finish putting together the timing-sync input channel and then we can test it.  I think Ray is going to buy some more tools first.

Meanwhile, I will continue working on my slides for January's workshop on the Python server code.

LabView sent us a quote for 1-year renewal of the development suite license, for some reason.  I don't think we're going to renew since we haven't been using it anyway.

We picked up the Tektronix cable.  There was only 1 cable instead of 2 as I expected - was I wrong before about how many came in the package?  Still, that's enough to assemble our 3rd detector.  Ray said that's the only other part we need.  Went ahead and did receiving on the cable.

Trying to get through to Altera on the phone to see if they can tell us why the CLK_OUT output is only producing a 1.5V pulse (instead of 3.3V as we expected).  They were in a meeting, said try again after 5 pm.

I measured the resistance between the PMT_3 node and the other side of the J60 jumper.  It is 1kohm, which is the resistance on the pullup resistor.  This kind of suggests that the PMT_3 node is somewhere shorted to the +2.5V supply directly or through a small resistance.  (Maybe that's why this supply voltage is only +2.4V as measured, because the voltage is sagging due to a short?)  Also, across JP14 which directly measures the +2.5V supply, there is only 1 kohm resistance there as well.  There is also about 2 kohm resistance (a bit more) across J59, which is consistent with a short between PMT_3 and +2.5V, plus a 1kohm between +2.5V and ground, plus the 1kohm pulldown R102.

Aha, I directly measured the resistance between PMT_3 and pin 1 of JP14 which is the +2.5V supply, and it is only 10 ohms!  (9.63 ohms, to be precise.)  This accounts for the problematic DC offset.

I'm wondering if cleaning off the board with an electronics cleaning spray might help.  Ray says try it.  I sprayed the board down pretty good in the sink, and am letting it dry overnight.

I ordered some "shorting jumpers" (what I call "jumper bridges") from Digi-Key.  Pack of 100, to be delivered to my home address.  This will cut down on the number of jumper wires we need.

Going back to the presentation now.  For reference, here is the module hierarchy I sketched yesterday in OpenOffice Impress (based on my handwritten notes from a couple of years ago).

First draft of COSMICi server module hierarchy diagram.

Now I'll start describing the new components.  I'll go bottom-up.  I'll start with "flag" (at the lower-right corner of the hierarchy).

Finished a couple of slides on flag.py and the Flag class.  Next up: timestamp.