matt.hoy
Member
I am trying to use a ML1500 to communicate with a barcode reader via ASCII protocol. It isn't working, so I tried to verify the reading/writing using hyperterminal. I don't seem to get anything in either direction. The write instruction's done bit goes true. The read instruction errors out with a code that says the protocol changed during execution of the command.
Because this PLC has only channel 0, I have to use the default comm button to get online with it via DF1. Then once everything is downloaded, I kill RSLinx. Cancel the default comm button, then I connect with hyperterminal. I clear the buffers on the PLC by jumpering an input that is a condition for the ACL instruction. Then I send a string with hyperterminal. Then I read using the ARD instruction (again by jumpering an input terminal since I can't get online).
After all that I use the default comm button to get back online and see if it worked. (results mentioned previously)
It is almost as if the code is executing, but the buffers are never actually processed. I have tried everything I can think of! Any ideas?
Because this PLC has only channel 0, I have to use the default comm button to get online with it via DF1. Then once everything is downloaded, I kill RSLinx. Cancel the default comm button, then I connect with hyperterminal. I clear the buffers on the PLC by jumpering an input that is a condition for the ACL instruction. Then I send a string with hyperterminal. Then I read using the ARD instruction (again by jumpering an input terminal since I can't get online).
After all that I use the default comm button to get back online and see if it worked. (results mentioned previously)
It is almost as if the code is executing, but the buffers are never actually processed. I have tried everything I can think of! Any ideas?