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    User name mercado

    Log entry time 15:20:57 on August31,2009

    Entry number 287240


    keyword=Another HAPPEX DAQ Change

    This morning right before the access ended, I was able to go into the Hall and 
    switch out the 18bit ADC (adcx5), which was showing weird csr values. I put in 
    place another 18 bit ADC (adcx6), which has a comparable channel range.
    As part of this change, ADC channel adcx6_0 started saturating in the negative 
    again when the detector cable is connected. To remedy this, I changed the 
    on-board offset DAC for that channel, and the signal went from ~-15000 
    (negative saturation) to ~400 channels.
    I did this by going to the file ~/dev_luis/config/ped_adcx6.txt
    and changing the last parameter of the first line. This value determines the 
    pedestal offset for that channel at gain=(3,0).
    The value was changed from 1746 to 600.
    A similar change was made for adcx5 on 8/30/09.
    The value was changed from 1979 to 1000.