scb41 232 with ascii

[JPM1 0]

I have a cqm1h with a scb41 and I am using the #0100 port to talk ascii to a pump. I am able to send one command to start the pump but when I send the stop command or any other command it does not activate. I think that the comm port is staying open. I can talk to the pump using hyperterminal and start and stop it like I want. But once hooked to plc it seems to locke open the comm port. The command string is as follows 1GO==node 1 pump start and 1ST== node 1 pump stop. I am using no start code with crlf as end code. I have tried in hyperterminal the 1GOCRLF and it works fine. I can start and stop as I wish. I am not sure what the difference is between hyper and the plc. I am not sure what could be causing this problem. Regards, Joey Tell me ill forget, Show me ill remember, include me and ill learn.

[PdL 71]

Please post a screenshot of the SCB port settings and your ladder code. This will help finding the cause of the problem.

[JPM1 0]

omron1.bmpI have included a screen shot in the attached file. Thanks for all your help. Edited 11 Dec 2008 by JPM1

[PMCR 66]

At first look, you may have a timing problem. Your use of 201.05 is correct. Is InitiateComms staying on? If so, it will always have first crack at the serial port, as it is higher up in ladder. Try using a DIFU instruction to create a one shot condition on the TXD. @TXD would not work in this situation, as the port ready flag would keep going off and on, retriggering the @TXD.