Controlling a RS-232 hot water bath

[jakers]

Hello, 

I am looking for suggestions on hot to control a water bath using a RS-232.  About a week ago I go the computer communicating with the hot water bath, using an LabView example called "basic read and write". Now I want to setup an experiment.  I want the Hot water bath to hit the following temperatures 30,50, and 30 again over a 3-hour time period.  The temperature increase from 30 C to 50 C should be gradual and the decrease from 50 C to 30 C should be gradual as well.  What kind of code do I have to write in order to do this?

Where should I start? Any help is much appreciated!

Jack

[Albert.Geven]

maybe give us some more information on the water bath and even the documentation that came, how to use basic serial read/write

[jakers]

The water bath is a VWR water bath, model 1167P, circulating bath. (see link below)

https://us.vwr.com/stibo/hi_res/VWR_Signature_Circulators_Operation_Manual.pdf

I found the basic read and write example in LabView.  LabView-->Help-->Find examples.

Then Search: Basic Serial Write and Read.

Once that was open there are two boxes. 1. string to write and 2. read string.

In box #1 I wrote in the format given on pg 41 of the Operator Manual for a set point.

In the second box it gave me a ! meaning that it read it, and the temperature slowly increased to the setpoint of 25 degrees C

Jack

[Albert.Geven]

Seems to work then. Cable seems ok, and all You have to do is find somebody close that helps you with the easy labview programming. 

Most of the time people have already a real driver layer ready and still don't get it so far.

An alternative isto wait until somebody has done this already

[jakers]

OK.  

I have been looking at this website

http://cnx.org/content/m12211/latest/?collection=col10241/latest

What topics should I focus on?

Jack

[jakers]

Hello,

I was trying to set a setpoint going off the manual(see above) using the format SSxxx.xx[CR]

This is how I put it into lab view to get a setpoint of 30 Degrees C   SS030.00\r

Shouldn't that work?

[jakers]

Also How would I get an Internal Temperature if the format is RT[CR]

Jack

[johnsold · Accepted solution]

Jack,

When you sent "SS030.00\r" to the device, did you have the constant or control set to '\' Codes Display?  String controls and constants have multiple display modes.  Depending on the mode, what you see is not necessarily what you get.

That string in a Normal display mode would end with the characters backslash and "r". If the display is in the '\' Codes Display mode then it would end in <carriage return>.

Lynn

[Dennis_Knutson]

The setpoint command should work as long as your string control/constant is set for \ Codes Display. This is a right click option.

To read, send the RT\r with a VISA Write and then do a VISA Read.