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I have a CompactRIO
system with two NI cRIO 9401 8 Ch, 5 V/TTL High-Speed Bidirectional Digital I/O
Modules.I am trying to output digital
data on one of the NI cRIO 9401 module and read it back on the other NI cRIO 9401
module.I am using a single 25 pin cable
to connect the two cards.This does not seem
to work.What am I doing wrong?
I hope you're doing well. You should be able to read the digital outputs of one 9401 module with the digital inputs of another. I would make sure that each of the modules work individually by testing that the module is actually outputting the high and low signals as expected (simple digital multimeter should do). Also, are you mapping the pins 1 to 1 on both modules with your 25 pin cable? Be sure that the line you output your signal on is being mapped to the line that is being read from in the software as well. Besides this, the other thing to check is your software. There are shipping examples that demonstrate how to do digital input and digital output on different modules, so if you follow these, there shouldn't be anythign wrong with your VI. You can find these shipping examples by going to Help»Find Examples, then Hardware Input and Output»LabVIEW <version number> FPGA, and then Digital Input or Digital Output. Let us know if you narrow down the problem, or if you have any follow up questions. Have a great day!
Thaison V Applications Engineer National Instruments
