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    User name V. Sulkosky

    Log entry time 22:28:55 on September 16, 2008

    Entry number 243282

    This entry is a followup to: 243210

    keyword=Re: Scaler gates and target signals in L-HRS

    I connected the scaler gates (helicity and target spin) from the LeCroy 4616 (ECL-NIM converter) that Kalyan installed yesterday to the first channel of the I/O of the scaler modules in the LHRS trigger supervisor. Here is the gate map to scaler module: 
    4616 Channel        TS Slot           Description
=========================================================
1  (ECL - gray)        2         hel+, tar+ gate (normpp)
2  (ECL - red)         3         hel+, tar- gate (normpm)  
3  (ECL - purple)      4         hel-, tar+ gate (normmp)
4  (NIM)               5         hel-, tar- gate (normmm)
    The three ECL cables are very close in length and are about 2" longer than the NIM cable. I checked to see if the gates were working as expected. First I couldn't see anything from the 4616, then I discovered that gray ribbon cable was inverted. The red cable was in channel 16 not 1. While running the DAQ, I was able to verify both by the LEDs on the scaler modules and the xscaler display that the gates were working properly for the modules in slots 2, 3 and 5. The module in slot 4 appears to be ignoring the gate signal, i.e. the scaler is always counting. I checked the cable and signal from channel 3 in the LeCroy 4616. The signal is good and will gate any of the other scaler modules. I then used the gate from channel 2 to test the module, but this module still refused to respond to the gate. We will need to check this module to find the cause of this problem.

    A copy of this log entry has been emailed to: rom@jlab.org,kalyan@jlab.org,ycwang@jlab.org,