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
• General discussion

Need two things:

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:

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