How I can controling different pins of a serial port (DTR and RTS)

[flying_dutchman]

I have to control a switch via the serial port and for that I need to command individualy pin 4 DTR and pin 7 RTS. I undesteand that it can be done with a Visa property node but I don't have a clue how to use this property node in a VI!

[Dennis_Knutson]

Go to the VISA>VISA Advanced palette and put the property node on your diagram. Right click on it and select Change All To Write. right click again and select Properties>Modem Line Settings>DTR State. Right click on DTR State and select Create Constant. Pick the state you want (Asserted/Unasserted). You can create another separate property node for RTS or you can drag the property node to create a second element or right click and select Add Element. If you want to control the states with other than an enum, you can right click on it and select Visible Items>Digital Display to find out what the numeric value of the enum is.

[flying_dutchman]

Thank you for the reply! I must configure first my serial port with Visa configure serial port? The property node I have to connect it to something or is stand alone?

[Dennis_Knutson]

If there is a reason to configure the serial port, then do it first. If you are just controlling the handshake pins, I don't think you would need to configure it for data transmission but it wouldn't hurt. If you want to try to just use the property node, all you would need is a VISA Resource Name defined. You can simply right click on the reference input and select Create>Control or Create>Constant. Once you have a resource name, you can enter tha name of the port or click on the arrow to get a list of resources on your pc. If you are developing on a pc that doesn't have the port you will be eventually using, right click on the resource name and select Allow Undefined Names so you can enter any name you want.