I am working on a VB.net project. My hardware consist of NI PCI 6221, a SCXI chassis and a NI-SCXI 1102 board. I am reading 32 channels of continuous data, but sometimes the channels shift. Chanel # 1 moves to #3 and so on.... If I go to NI explorer the channels are also shifted in there. The ony way to set the channels back to normal is to reset the computer. already tried to reset the boards using NI explorer and it did not work. My hardware activates ansd deactivates relay. It seems that the noise of the commutation sets the hardware crazy and shift channels. My relays already have diodes in parallel with the coils and all my signals are shielded. Does any body have an idea?