Why Can't I Reset the Excitation Voltage of my SCXI-1520 After I Power Cycle It? Hardware: SCXI>>Modules>>SCXI-1520
Problem: I am running a SCXI-1000 chassis with a SCXI-1520 strain gague module. I can run my LabVIEW program that sets up the DAQmx virtual channel and set the excitation voltage to 5 volts. After power cycling the SCXI chassis the excitation voltage returns to zero (this is expected). If I run the program again, the excitation voltage does NOT get reset to 5 volts. However, if I try to set the excitation voltage to something different after power cycling it (4 volts for example) it works. How can I set the excitation voltage to the same value as it was before I power cycled my chassis? Solution: The SCXI-1520 uses an internal DAC to generate the excitation voltage. When you power cycle the device, it returns to its default state (no excitation voltage). The software driver for the device is unaware of the power cycling and still thinks that the excitation voltage is at 5 volts. It will not change the voltage (reset it) until it is assigned a different value. There is a way around this. You can simply place the "DAQmx Device Reset" subVI before you set up your virtual channel in LabVIEW. This reset will allow you to configure your excitation voltage even after power cycling the chassis. Related Links: Attachments:
Report Date: 10/05/2004 Last Updated: 10/08/2004 Document ID: 3E489HTY |
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