IntegrationDaq 210730
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Meeting information
Meeting time: 3:30pm Eastern BlueJeans calling instructions: Toll-Free Number (U.S.& Canada): 888-240-2560 Other BlueJeans access phone numbers are listed at https://www.bluejeans.com/premium-numbers Bluejeans CODE: 641 252 323 Bluejeans link: https://bluejeans.com/641252323
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
- 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. -- apparently Robin Wines made a template but I didn't find it yet.
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.
Minutes
Recording on Bluejeans.com:
Participants:
