Instrument Control (GPIB, Serial, VISA, IVI)

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Hexadecimal code for VISA-Temperature Controller

Greetings,

 

First, I am not a programmer by any means so please excuse my ignorance.  I'm trying to control an Accuthermo FTC100D temperature controller using LabVIEW 2013.  I'd like to be able to send it a temperature input (Set Value) at a specific time, hold it at that temperature for a specified duration, and be able to read back the temperature it went to (Process Value). 

 

I have controller attached to the computer using a USB/serial converter.  I know it's wired properly because it works with the Accuthermo software that was made for it.

 

Pages 8-11 of the attached manual specify how messages should be written and received from the computer to the temp controller.  According to the manual, "Both command and response messages consist of three fields — Address, Function code, and Data — sent in this same order. For all fields, the allowable characters transmitted are hexadecimal 0~9 & A~F."

 

Right now I just want to read back value at PV register, which is code 04 in the manual.  I also know that the controller should be address 1, as that is factory set and I haven't changed it.

So I tried sending the controller messages by sending a String constant--> VISA using some of the VI's in the topic below:

 

http://digital.ni.com/public.nsf/allkb/6C24F2F07BC23BB78625722800710865

 

However, the VISA kept timing out and I was not able to get a response from the controller.  I feel like this must be an issue with how I'm framing the message, but I'm pretty lost as to what I need to change.

 

Any help on this would be greatly appreciated!

 

Laura

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please post the vi  you used, but first save it after you have executed the edit command "make current values default".

 

In that we can inspect a possible error.

 

Another good thing is a serial catch of the data of the working program.

 

greetings from the Netherlands
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I don't know how helpful this will be, but this is what I tried.  Thanks for taking a look.

 

Laura

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I miss at least the initialisation code for the serial port.

38400 is not a normal default in windows

I'm now reading the manual further.

greetings from the Netherlands
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The next error is that you only send 4 bytes where 6 are needed for function 4.

So your starting address should be two bytes and the number of words should be two bytes.

 

greetings from the Netherlands
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