ICD LMB Interface

setup d0online
cd ~d0icd/vme/
./lmb_int.py & (Don't forget the period "." at the beginning)

The interface GUI (thanks to Marc Hohlfeld for writing the python script!) allows us to control both the DC offset (governs the amplitude of the SLP) and the delay of the TTL with respect to the trigger.

We are limited to setting only one DC offset and one delay value for each LMB (each ICD crate).

The first row of numbers corresponds to the DC offset, the second row of numbers to the delay.

There is one column for each ICD crate, Column 1 = NW, Column 2 = NE, Column 3 = SW and Column 4 = SE. The last column is for global control, mainly to turn off all at the same time. To commit a value, simply click on the Download button for the respective ICD crate, or globally. There is a single Read button on which you can click to reassure you that the correct values have been downloaded.

The DC offset values are in Volts and can be set in increments of 0.2 Volts from 0.0 to 10.0 Volts. The delay values are in ns and can be set in increments of 2 ns from 0 to 170 ns. If you try to download any other value, you will see one of the following:

For example, we initially set the DC offset to about 6.8 Volts with a delay of zero for the Southeast ICD SLP. At these settings, we saw from the pin diode readout, a value of 35 mV. The approximate conversion: 1 ADC count is about equal to 1/10 mV. At the BLS readout, the ADC value is about a factor of two smaller, such that this signal should correspond to about a signal of 180 ADC counts above pedestal. This also assumes the ICD signal is in time, which is doubtful (delay = 0). The cables going to the Northwest and Southwest quadrants are 30 feet longer than the cables to the Northeast and Southeast.

I have tried different values of voltages and delays, but the calorimeter timing has changed. At this time, I can only suggest that a minimum of 8 Volts is needed for a clear signal, but I don't have a clear recommendation for the delay.

At the end of your session, remember to set all DC offsets to 0 and then commit before closing the interface. Click on the Read button to confirm that the values are indeed zero.