ASCII Read & Write in ControlLogix

Hi,

I'm having some problems getting the ARD instruction to work for me in a CLX L-62. I have configured the Serial Port for ASCII and have being able to write sucessfully to both HyperTerminal and my ASCII device.


For a read I am inputting a string in Hyper Terminal but when i execute an ARD the Serial Port Control returns an error 004Hex.

Has anyone any suggestions.

Has anyone else experienced this?

This is my approach, this is a compact logix.

I'm send program and serial port config.

This is a bar code reader.

Hi Bill,

My config is the same. My ACB count is always zero and .ER is always active. I have tried setting this up with Hyper Terminal too and still cannot perform a read?

This error normally happens if your serial port is configured as System... is it?

Should be configured as USER, otherwise read is not possible.

- [font=comic sans ms,sans-serif]fuzzy logic[/font]

Verify cable from pc to serial port, it can be the same cable used for programming, check hyperterminal config, try to clear the buffer as shown in first rung. .ER should be off.

Guys,

I had Serial Port set for System. Oops!I have changed this to user and now Im getting a little further. The .ER is gone now but I'm still not reading any data. I am attempting to read 4 characters from HyperTerminal.

Any more suggestions? I'll post a zip my logic. Cant figure out how to past a screen shot here.

Thanks

Morphius, your logic is ok, if your pc is connected to the plc serial port and you´re running hyperterminal just write down something on hyperterminal and then press return that should be enough to send some caracters from pc to serial port.

Ok. Have it working. Sort Of!!! I'm reading back some jibberish from the device. I think its because the amount of characters been sent is always varying.

Have to see if the device sends some sort of temrinating character to tell me when it has sent me the reply to my request.

Morphuis, yes when you type several keys on your keyboard while on hyperterminal and you then hit RETURN, what you have typed is sent to the serial port together with control characters like line feed and carriage return, so please take into acount this characters, i know there is a way to configure sending characters in order not to carry control characters, but that has to be done inside the device that is sending data toward the plc, otherwise take into account all the characters being sent and enhance your buffer and number of characters expected.