Serial Communications link to Eurotherm mo. 818 controller

[Timman]

In the past I have had no problems in Lab View 5.0 communicating with Eurotherm 808 or 818 controllers.  I send a remote temperature setpoint that controls temperature to a heated plate.  Also I send a message that locks the power at a percent that maintains the steady state temperature set point.

When I converted to LabView 8.0 I now am unable to communicate with the Eurotherm 818.

Our field service guy - Brigham Steele tried unsuccessfully to remedy our situation.  I have done as he has instructed by reinstalling LabView 8.0 and installed all of the updated software and drivers.  I also went to NI serial and obtained all of the updated but not supported Eurotherm VIs and installed them.  I can perform a serial loopback test on the PCI 8431/2 485 card and the old 485/AT catd (LabVew 5.0) and they both test OK using either the serial communications vi in 8.0 or the read vi and the write vi in 5.0.  When I try to establish a communications link with the Eurotherm 818 I get two error messages about having no data at the serial port - like the Eurotherm fails to respond or doesn't send any message back to the PCI card in the computer.  This model controller worked great in Lab View 5.0.  I even tried going back to Lab View 5.0 computer with the 485/AT card but got the same error messages.  No data at the serial port error (-1073807343).

The Eurotherm 818 is set up for ASCII transmit and receive messages per the 485 4 wire communications card internal to the device.

I have sent a technical request into Eurotherm as well but have not received a response back yet.

It has got to be something simple I am overlooking - maybe.  Any help out there?

Thanks,

Tim

[Brian_Beal]

Tim-

Did your program use the old serial VIs?  Are you now using VISA?  Download a SCADA program called Specview, www.specview.com.  It is free and will run for 10 minutes without a license.  It will autodetect the 818.  Just tell is what protocol you are using (Bisync) and the comm port to look on.  This is an excellent way to test your wiring, etc.  Other than that, check your wiring, since Eurotherm's 485 nomenclature is backwards from almost everyone elses.

[Chris_R.]

Hi Tim,
Also, make sure to update and reinstall your NI-VISA drivers.  I recommend the latest version.  Click here to access the download page if needed.  VISA needs to be reinstalled after LabVIEW 8.0 is installed so the new LabVIEW 8.0 directory has the VISA functions.  As Brian suggested, also check that you are using the new VISA VIs and not the old Serial VISA VIs from older versions of LabVIEW.  Let me know if you have any questions!

Chris R.
Applications Engineer
National Instruments

[Timman]

Brian,

Thanks for the information on Specview. 

To date I have downloaded Specview.32 version 814. I go into demo mode and set up for test communications for new configurations.  In the list of devices is Eurotherm 2500, Euro_M8, and Euro 26/2700.  May I use any of these for my 818 because I do not see Eurotherm 818 as a specific option to choose from the list of devices.

Timman

[Brian_Beal]

You should have a variety of 818 types to chose from.  Any one should work, you just may not have all of the right parameters.  I don't have Specview on this computer, but the 818 is probably under EI-Bysynch in the instrument list.

[mdiflying]

Hi Tim,

We are trying to let the computer talk to the Eurotherm 818 controller.

Can I know where do you get the drivers for the communication between 818 and the computer? or did you write the code yourself?

Thanks for your reply.

Lingbo