How do I program the pedestal of the Caen 792 N QDC module using LabView?

[Shamil]

Hello everyone,

Here's a problem. I'm trying to reprogram the pedestal of the Caen 792 N QDC module and it doesn't seem to work. Using LabView I'm writing into the Iped register (Base address + 0x1060) different values for the pedestal, but the pedestal doesn't change at all. It always stays at 58 QDC bins approximately 5 bins wide.

I'm writing different values from hex 0 to hex 300, but I have no clue to what Ip (programmable current) they correspond, because the pedestal doesn't see to shift at all.

Does anyone have any good thoughts about it? What could I be doing wrong? Or is it that the QDC is "funny" and needs repair?

Thank you.

[Nitin_T]

Hello Shamil,

I had two questions

1) Which Register VI are you using to access the device.

2) Are the error outputs from these Register VIs clean ie. no errors?

Thank you

[Shamil]

I'm using XX-USB_VME_Write_16.vi from the Weiner XX-USB version 3.3 package http://www.wiener-d.com/Support/XXUSB/XX-USB_CD3_3.zip

Caen VME Crate, Weiner Controller, Caen QDC module, LabView 8.2

[Shamil]

How would I know if outputs have errors? Would the program complain and return some specific outputs? And at what outputs in particular should I look?

As far as I understand it, it doesn't complain, the DAQ program that I use to take data runs just fine, except the pedestal always remains at 60 qdc bins.

[Nitin_T]

Hello Shamil,

I would suggest using the error out line that is available on the Call Library Function Node of XX-USB_VME_write_16.vi. Also, check for the return value. If the dll that is being called is configured to return error values, then you will be able to see it.

Also, there are two VIs that can be used, the XX-USB_VME_write_32.vi and XX-USB_VME_write_16.vi. I believe it is talking about the size of the register you are trying to write to (32 bit or a 16 bit register).

[Shamil]

Thanks for your help. I'll try to do as you said and see what happens.