I'm trying to communicate with a Hart 1502 temp meter. It's easy and works with an interactive terminal (PuTTY, in serial mode) but does not work with LabVIEW. Well, as far as I know, the meter works fine but something is subtly different about the communications and I hope someone here can shed some light.
Basically, when I send "t\n" it returns a temperature and some other stuff.
I've been using the same serial-port VIs for a while and have had success connecting to a variety of other hardware.
Things I've tried:
0. Got out a DMM and checked the cable
1. Checked, re-check, re-re-checked the serial settings of the device. This includes rate, data bits, parity, stop bits, and hardware control.
2. The termination character from the meter is CR or CR+LF. I've set to CR+LF and set the VISA init function so.
3. I've tried sending "t\n" and "t" followed by "\n" in case the meter is confused by line-by-line input instead of character-by-character input. Shouldn't be a problem but it was suggested elsewhere so I tried it.
4. Re-starting the computer, in case of some unlikely VIAS issue
5. Used a co-worker's set of VIs for opening the port. Same issue.
6. Turned full-duplex on. At first, I observed only the echo of my "t" transmission but nothing else. Also, turned it off.
Does anyone know what's going on here? Even if you don't know, give me a homework assignment that could illuminate the situation.
I'm using the init, close, and first read-until-expected-string functions in the attached library.