Anyone with experience on RS-232 comms with Tenma DC power supply, ThermoOrion pH meter or kdScientific syringe pump?

[Maria Villareal]

I am using LV 6.1 with Windows 2000 and trying to communicate serially with Tenma power supply, ThermoOrion pH meter and kdScientific syringe pumps via RS-232 cable. I've done the hardware test to ensure the serial cables are working and the computer can send and receive signals. However, when I use "Serial Communication.vi" to talk with each instrument, there is little evidence that anything is happening:
Tenma power supply--goes into "REM"ote mode, showing it recognizes something from computer, but then only makes 3 or 4 beeps when writing a command to the power supply

ThermoOrion pH meter--no evidence that commands from computer even get to met
er

kdScientific syringe pumps--will go into "REMOTE" mode and every once in a while will provide some feedback to the computer, as if it's trying to respond, but response is gibberish and commands from computer have no effect on operation

If there is further information I can provide that might help, please let me know.

Adios

[DiegoF]

Hi Maria,

Make sure the serial the serial settings match between the device and the PC:

- Baud Rate
- Number of data bits
- Number of stop bits
- Parity
- Handshaking mode

You can also use the Windows Hyperterminal as a good troubleshooting tool. Do you get the same behavior if you use Hyperterminal?.

DiegoF
National Instruments.

[Maria Villareal]

Hello, Diego,
Thank you for your feedback. I've since been able to control the power supply through LabVIEW. I'm holding off on the pH meter and concentrting on the syringe pumps now.
I checked all of the attributes you noted and they match between the syringe pump and the LabVIEW program. I used the Windows hyperterminal with the pumps and were able to control them just fine, so only when I go to LabVIEW control via "Serial Communication.vi" do I get the sporadic communications. Any further insight?

Thank you.

[DiegoF]

Hi,

What exactly do you mean by speradic communication. If you get random timeout errors, I would suggest increasing the timeout value. You might not be giving the device enough time to process the data and send the response.

DiegoF
National Instruments.