problems with connecting to SP Scientific Chiller, MPC

[rhelling]

I am trying to connect to an SP Scientific RC211 Chiller. I attached the relevant part of the PDF manual. It says the chiller has an MPC, which I was assuming was MultiProtocol? I have an RS232 cable connected with a null modem adapter as the manual says to do. When I connect the chiller I never can get anything to show up in the Device Manager, and I wrote a .vi (LV 2015) that should be communicating with the COM port that the chiller is connected to, but I get an error that says I probably dont have the correct drivers. Is there a MPC driver that you can download? Anyone have experience connecting with these things? I have the serial parameters set up correctly. Thanks in advance any input is appreciated. 

[Dave_Brandt]

You have to send ASCII commands (text) to the chiller. Anything you get back will be readable text. So you need to check your settings. Baud rate, parity, flow control, stop bits. Both sides must be the same or your data will be useless. Check that first. Also do a loop back test on your pc to ensure you have the correct setup on your pc such as com port. (remove cable from chiller and Short pins 2 and 3 on your cable) This will loop back what is sent form your pc. Read some basics of rs-232

http://www.engineersgarage.com/articles/what-is-rs232

[rhelling]

I am sending text commands to the chiller. I get an error before I even get to the VISA WRITE. The first part of my test code is VISA OPEN and this is where I get an error. I have baud rate, parity, etc. all correct. I have not done the loop back test, but I have tried using a USB to Serial converter which is being recognized by the PC. If there was a way to see that the chiller was being recognized by the PC that would be helpful. Can i just send ASCII data to the chiller straight from Labview or should there be a certain driver installed?

Also usually when you put a constant next to one of the VISA modules you get a drop down that has different COM ports selectable. Currently nothing shows up...

[RavensFan]

When you say you have an error message, then tell us what the error message says.  Does it have an error number?

Your USB to serial adapter is what you need to install drivers for.  Does it show up in Windows Device Manager?  Does it show up as a serial port in Measurement and Automation Explorer?

There would be no driver for the chiller itself.  Windows and LabVIEW have no idea of the existence of the chiller.  All they know is there is a serial port that you send ASCII commands out of and expect to receive ASCII responses back from.

[rhelling]

The error message is -1073807202 which is "Unable to start operation because setup is invalid (due to attributes being set to an inconsistent state)". 

The USB to Serial Adapter shows up in the device manager and I have the latest driver for it. 

Good to know that there is no driver for the chiller itself, think I was getting hung up on that a little. Maybe I need to convert the text to a numerical value? 

[RavensFan · Accepted solution]

That description doesn't match that error number when I look it up.

I see this:

"Error -1073807202 occurred at an unidentified location

Possible reason(s):

LabVIEW:  (Hex 0xBFFF009E) VISA or a code library required by VISA could not be located or loaded.  This is usually due to a required driver not being installed on the system.
=========================
VISA:  (Hex 0xBFFF009E) VISA or a code library required by VISA could not be located or loaded.  This is usually due to a required driver not being installed on the system."

Going by that description, I question whether you have VISA installed properly.

Have you tried opening up a session within MAX and sending a simple command?

[rhelling]

So the problem was definitely what RavensFans described, the VISA software was not installed on the computer. Guess that is pretty obvious, but I have never had to install it before I figured it would install with the software.. Once I installed the software I was able to create a VI that interfaces with the chiller. Thanks for the help everyone. One weird thing is I am unable to control the chiller via NI MAX, however it works in Labview as well as Hyperterminal... Not too worried about this because it works in Labview.