Why Do My Digital Output Lines Not Output a Digital High?Hardware: Digital I/O (DIO)>>Isolated>>PCI-6517, Digital I/O (DIO)>>Isolated>>PCI-6516
Problem: I have a device with digital output lines. When I test the card with a digital multimeter, the outputs will not output a logic high when set to high. What is wrong with my card? Solution: If your DIO device can output 24V or greater, the digital outputs require that an external power supply be connected. For example, if you are using Port 0 as an output port, you must connect VCC to the positive lead of an external power supply and COM (GND) to the negative lead of the power supply. The power supply voltage should range from 5V to a voltage below the maximum digital output voltage rating of the device. The digital output port will then switch between 0V and the supplied voltage. Depending on your device, there may also be +5V reference pins that are not outputting a high. This is because the voltage is derived from the user-provided VCC. If the VCC is powered using an external power supply then the 5V lines will behave as expected. For more information about how to connect the power supply to the correct pins on your device, consult the user manual for your device. Related Links: Product Manual: NI 651x User Manual (March 2007) Product Manual: NI 6232/6233 User Manual (July 2006) Attachments:
Report Date: 11/28/2006 Last Updated: 10/17/2008 Document ID: 43RHELQ0 |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
