how can i know the external input related to the alarm of wire stick

look at your wiring diagrams or back trace it in CIO

The alarm is a result of at least two bits. One is the alarm request (need to know what controller you have to tell you the address, but you can find it in the CIO manual) and the binary bit or bits to set what message is to come up, once again look in the CIO manual for the controller you have to fine the user alarm bits. Depending on who programmed this alarm to come on, there could be a common bit to make the request and the selection come on, or there could be rungs and rungs of data to make the robot do what the engineer wanted it to do. You will have to work backwards to find what makes this alarm come on.