IntegrationDaq 210730

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Meeting information

 Meeting time:  3:30pm Eastern
 
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Agenda

• Progress on prototype
• Requirements document needed. From Jim's message: "we need to get the requirements for trigger/DAQ documented and Rev 0 approved prior to our annual review this fall"
• Follow-up on discussion of input impedance to match beamline signals
  • Some signals will be from SEE electronics and some from new receivers; need to follow up further about new electronics
• General discussion

Need two things by end of August (no hard deadline). Some of this is just cut/paste from existing docs.

1. Design requirements document -- examples and template : http://userweb.jlab.org/~rom/mollerdaq/design

2. ICD -- interface control document(s). -- apparently Robin Wines made a template and it's on sharepoint. It seems we need several of these (infrastructure to DAQ; detectors to DAQ, etc).

Resources

Response from Tom Powers about beamline sample and hold card output

Here is a schematic of one of the channels, which is in the EECAD directory as well as document control.

The LM6321 is a 50 Ohm driver with a gain of 1. The topology of having the 50 Ohm resistor where it is makes it such that the circuit can put out as much as +/-10 V to a high impedance load and +/-5 V to a 50 Ohm load. The topology is also such that the output voltage remains the same if you have a high impedance load or a 50 Ohm load and so long as you do not exceed +/-5 V.

The target value for the SEE wire signals is about 3.5 V or minus 3.5 V depending on which output channel you use. Thus it is a don't care on the load type.

My advice is that you can use high impedance for a local data acquisition system but it is recommended that you use a 50 Ohm termination if you are running long cables. Just remember that you only get one 50 Ohm load per signal.

Response from Jay Benesch about BPMs in the Hall

Five of the seven BPMs in the hall proper will be short machined striplines which use the digital receivers designed for arc 10 and Hall D. Only these will fit given optics requirements and keeping the polarimeter locations fixed. The other two may be existing SEE BPMs or may be changed as there is space downstream of the Moller polarimeter where shielding was once to go.

...

All the BPMs in the BSY and alcove will remain SEEs.

Minutes

Recording on Bluejeans.com: [1]

Participants: P. King, J. Fast, R. Michaels, M. Gericke, B. Moffit, B. Shaw, W. Gu, J. Pan, D. Bishop, B. Blaikie

• Progress on prototype
  • Daryl has finished and has passed the layout and BOM to Jie to send it out for manufacture (Daryl will be on vacation for the next month)
  • Michael suggests seeing if there are parts on back-order that we can swap out without a redesign
  • Daryl also suggests checking with the fabrication company to see if they might have some of the back-ordered components in stock
• Follow-up on discussion of input impedance to match beamline signals
  • Daryl says that he did change the footprint for the input connectors so that we could use either the twin-ax or BNC connectors, and could select 50 ohm input impedance or not, so we ought to be able to handle either the 50ohm or high impedance connections
  • Bob suggests bringing Mark Pitt into the discussion with John Musson about what the beam monitor needs for parity are
  • Bob recalls that PREX2/CREX didn't end up using the digital cavity BPMs in the analysis. MOLLER will need to be able to use the digital receiver signals, so we need to be sure we're getting what we do need from them
• Requirements document needed
  • Bob and I will work on these together first, then bring others in
• General discussion
  • Michael asks Bryerton about the firmware work for the prototype board