Thermotron Chamber controlled by Labview

[jd83]

Hi

I am hoping to control a Thermotron Se600-3-3 chamber that has a 7800 controller with Labview through a serial port interface.

Would it be possible to use a serial to usb connected to a computer?

The current 7800 controller has some faults on it and wont run a porgram does this matter when using labview through a serial port?

A step by step guide of how to get this started would be great or any help what so ever.

Thanks John

[ssk]

Hi, yes it would be possible to use a USB-Serial converter as your interface. You will need to know the communication protocol and commands for the chamber - do Thermotron issue those?

[jd83]

Thermotron offers the drivers that labview supports on request and im not sure if theres a fee involved, this is one of the reasons i need to know if its possible and if it is possible how difficult is it to do and is it worth my time

[NIquist]

The LabVIEW drivers are a free download from NI :  http://sine.ni.com/apps/utf8/niid_web_display.model_page?p_model_id=1367

You can probably auto-install them with LabVIEWs IDN:  Tools > Instrumentation > Find Instrument Drivers...

Be aware that many USB-Serial converters don't provide hardware handshaking.  If the oven needs it to communicate you may have to try several USB converters until you find one that works.  Or, just get a PCI card.

Depending on how complex your control App needs to be talking with these ovens is quite straight forward once you install those drivers.  Good Luck...

[jd83]

The 7800 controller that we are using at the minute is not storing any programs. For labview to control the chamber is it necessary for the controller to be working properly,

Thanks John

[jd83]

I am using a USB to Serial connection, with a 3 null RS-232 cable.

I have downloaded the drivers and placed the file in the correct location and mass complied as per instructions.

I have also placed the .dll file into the correct file which I created

Next I am trying to send commands through the visa test panel but I am still receiving a time out error

Have you any ideas were I am going wrong.

[NIquist]

The DLL's and other software are not important yet.  First you need to establish communication with the 7800.  You can write a SCPI command through the NI-MAX VISA test panel called *IDN?.  That should cause the 7800 to send back an ID string so you'll know you're communicating.  

Before that works you'll need the right cable and the right COM port settings.  I hope you have the 7800 manual because they are not readily available on the web for some reason (need to own the oven or pay?).  Check it out and see what cable is required and what the default COM setting are for the 7800.  I don't know what a "3 null RS-232 cable" is but I assume you mean a null modem cable.  That is probably not correct.  I would suspect you need a standard (straight through) DE-9 serial cable.  You will also need the port settings to match.   Baud rate, data bits, stop bits, parity and flow control must be set the same.  If you aren't sure about the settings you may have to play around a "bit" 

Try a straight cable and see if you get any response.  Hopefully you have their manual.  If not, you can get it here but you have to buy it unless you can prove ownership or some sillyness   http://www.thermotron.com/contact/replacement-request

Friendly warning:  These older ovens are not the most friendly things to program or control remotely.  Expect to need to read the entire manual. 

[jd83]

im slowly finding that these older ovens are not too friendly at all!

I have a piece of software to test the comms and send commands to the oven. At the moment i have not  made any communication with the oven.

I have the right parameters in place like baud rate etc.. the interface cable im unsure about and am testing with both a straight through rs232 cable and a rs232 cable that have the rx and tx crossed like below.

This was on advice from a thermotron engineer, but i have since got my hand on the manual and it makes no reference to this type cable.

Connector 1	Connector 2	Function
2	3	Rx		Tx
3	2	Tx		Rx
5	5	Signal ground

[Dennis_Knutson]

Please attach the manual.

[buton]

yes... please attach the manual..