I'm having a problem with my input/output rack or cards. Recently one my robots have stop have stop responded to the inputs that are given in its instructions.I don't have any problems with the outputs. The following things that have I checked thus far are listed below.
1. Checked the supply voltage to the I/O cards. - Checked ok.- There is 24vdc volts being supplied to the I/O boards.
2. Checked the output voltage off the ribbon cable and the input voltage feeding the relay when the input is turned on. - Checked ok. There is 24Vdc going out from the I/O board to the I/O card when the input is turned on andv verified 120vac to turn on the relay to the input.
3. Swapped and changed I/O cards in the rack to see if the problem would follow. - No change.
4. Checked I/O cards to see if they are receiving the inputs. - YES, the led is on the I/O cards are lit when receiving the correct inputs.
5. Swapped out CPU card. - No change. Problem still exist.
6. Checked the instructions for the input in the program. - Didn't see anything or changes in the program. Made a simple program that would make the robot respond if and when the input was received.
Only thing I haven't done is swap out the back plane that connects the I/O's and the CPU. What are my chances the back plane that connects the boards in the rack going bad.
Is there anything else I should be looking at?
Help would be highly appreciated