Functional difference between VISA resource name ASRL1::INSTR and COM1

[THzMan]

Thanks for both replies. I figured the port I was using and how to set them up using MAX. I can communicate (write commands) with the device (LakeShore 208 Thermometer) now, but I still cannot read it.

I get the timeout error. My vi is really simple but I still dont know what I am doing wrong with it. All the values for the VISA Serial Config are the ones that my device's manual specifies.

I also included a jpeg in case you cant open the vi. Its on an old version of labview (v 6.0).

I would really appreciate any help. Thanks.

[Dennis_Knutson]

First of all, did you first try verifying communication with a program such as Hyperterminal? If that works, you know you've got the correct settings and are using the correct type of cable. Second, you are sending a command followed by a space. Is that the correct format or do you need a termination character such as a CR or LF at the end. There is no error checking on commands being written so verify that.

[THzMan]

I checked the com port with hyperterminal and it seems to be fine. Besides like I said before, I can write commands to the device, but my problem is that i cannot read from it. About the space and the termnating commands you are right.

That space should not have been there and I was using \n (from MAX's I/O with the port) as a terminating command, but I tried with and without that and it did not a difference.

[Dennis_Knutson]

But are you sending the \n correctly? In the VI that you attached, the string constant is not set for '\' Codes Display. Right click on it to change and see if that makes a difference.

[THzMan]

Wow! I would have never figured that out on my own. I had no idea about the '\' Code Display for strings.

Thank you very much. It works now.

[com3]

i am a new developer. i was using rs-232 com port previously in the desktop, but i need to switch over to usb port now. It shows me now ASLR:INSTR3 now in my laptop and i want to know if it is talking abount my usb port or what else

[Dennis_Knutson]

If you have a USB-RS232 converter plugged in, it's that. If you have a built-in RS-232 port, it's that.