RS232 communication with Device

[theboybatis]

Hello,

I am trying (with little success) to control a valve controller using Labview VISA. I've enclosed a PDF of the manual, I'm using the DIN protocol/BDZ + Syntax described on page 41.

I'm using a program similar to the the basic read and right, I've got the Serial Configure function set with the values in the manual and the VISA write sending <ADR> (01 in this case) and <ENQ> as described in the manual on page 43. I've got the DIP switches set to address 01. I've got a scope on the TxD wires and the message is going. I've got VISA read coming out but nothing is being recieved ( should be <ADR> <ACK>), I've got a scope on the RxD wire and nothing is signalled whatever I do. Apparently I should get a  <NCK> response to all incorrect commands.

Does anyone have any thoughts, any help would be much appreciated.

Many thanks

Stephen

[Dennis_Knutson]

You really need to attach your program so someone can see how you are sending the commands. Sending the strings <ADR> and <ENQ> would be certainly wrong.

If you have a string control that you use to enter commands, enter the command in the control and then select  Edit>Make Current Value Default. Save the VI and attach it.

You will also need to verify that you are using the correct cable if nothing is shown on the instruments RxD line. If you have the incorrect cable, the instrument will not receive anythingat all to acknowledge.