VISA timeout error

[jmountney]

Hello,

I am trying to interface a Watow F4 Ramping Controller into the LabVIEW environment through the serial port COM1. I am currently receiving a VISA timeout error when I try to read or write data. I have checked the following which describes possible solutions: http://digital.ni.com/public.nsf/allkb/874B379E24C0A0D686256FCF007A6EA0 . I have also checked that the communication parameters are correct (baud rate, parity, etc.). The VIs that get installed along with the instrument drivers include an initializeVI.vi which sets the timeout value to 5000 ms (3000ms longer than the LabVIEW default). I also tried increasing this to 10000 ms, which results in the same error (Error -1073807346). I assume I  must be overlooking something.

Any suggestions are greatly appreciated. Thank you.

[Dennis_Knutson]

That article does not come close to explaining the more common reasons for a timeout with serial. You could have the wrong type of serial cable, the wrong termination character, or the instrument is not configured for serial.

[jmountney]

Dennis,

I agree with your comments. However, Watlow produces their own software for interfacing through the serial port which I was able to successfully use to communicate with the F4 controller and read configuration parameters from the device. So, I am almost ceratin that the hardware is good to go. Thank you for your input.

[Dennis_Knutson]

That is essential information that you should have provided in your first post. Since you say it is good to go, then i'll assume you don't need any more help.

[jmountney]

Sorry, when I said the hardware was good to go, what I meant was the controller, cable and com port all seem to working poroperly when I use Watlow's software. I am still having issues on the LabVIEW side with timeout errors. Is there some obvious configuration of the VISA that I am overlooking?

[RavensFan]

Are you doing something like not using the correct termination characters in your LabVIEW code?

This is all a guess since you haven't attached your VI so we can see what you are doing.

[jmountney]

I have attached the VI. However, in order to run it, the Watlow instrument drivers must be installed. These can be easily obtained from within LabVIEW by clicking on Tools->Instrumentation->Find Instrument Drivers. Then select 'Watlow' from the Manufacturer drop down menu and choosing wlf4 'Instrument Driver'.

I tried changing the termination character, but this did not seem to improve anyting. The error appears to originate from the Visa Open function, which is located in the initializeVi subvi. Thank you for your time and help.

[GreaseMonkey]

jmountney,

I am just getting starting on trying to control my Watlow controller.

Some things to double check,

Verify what port (COM1) make sure it is the same in LV as your OS.

Second verify your Baud rate is set correctly. (if you are using a Test Equity chamber look at their docs for the correct setting if not verify with what is set in the Watlow it self)

(I usually try to start with a basic "who are you" command that gives a single response to verify the port and basic connection is working before I get into the more complex commands/communication)

I will let you know how it goes on this end.

Ryan

[jmountney]

Thanks grease monkey,

I was finally able to get LabVIEW and the F4 controller to communicate yesterday. The problem was the termination character for reading data. However, for the life of me, I can't figure out how to get the VIs to work properly. Many of the example VIs I come across in the discussion forums still give me timeout errors. All I am trying to do is use the Static Setpoint Control mode. I am not worreied about profiles or the like. Once I can set a temp or humidity setting, I can use LabVIEW to regulate temperature as a function of time. I attached my basic VI that I have so far for configuring the port. Let me know if you make any breakthroughs.