temperature control in Labview using serial communication

[VYBH]

hi

I am using thermistors to measure temperature. Based upon their readings temperature will be controlled using programmable power supply. (LAMBDA ZUP-120)

This power supply can be serially communicated from PC.

I am planning to use Labview.

Please give me rough outline about implementaion of this  serial communication activity in Labview.

Vaibhav Khane

[Chris G in AE]

Howdy Vaibhav,

LabVIEW is a great choice for communicating with a serial instrument.  I've attached an overview of how to set one up to work with your LabVIEW program.  This uses the NI-VISA driver, which is talked about in the article.  Also, check out the basic NI-VISA tutorial.  Please let me know if this answers your questions, and have a great day!

[VYBH]

Hi Chris

Thanks for the information.

I have tried to configure the device in measurement & automation explorer.

But this device is not shown under devices & interfaces.

I am using ZUP 120 3.6 programmable power supply.

I am using Labview 8.5 & Vista as an operating system.

I am using USB to serial adapter for cable connecton.

The serial cable i am using is having DB 9 female connector on one side & 8 pin telephone ack type connector on other side.

Let me know why this device is not being shown in measurement & automation explorer.

my mail address is vaibhavkhane2u@gmail.com.

Please drop me a mail  so that we can have faster way of communication.

Vaibhav

[VYBH]

one thing forgot to mention

This device is being shown in device manager of windows as Prolific USB to Serial communiction port.

Let me know  what is the problem if any?

Vaibhav

[Dennis_Knutson]

It's a little unclear if you mean the power supply or the USB->RS232 is not showing up in MAX. If it's the power supply, it's not supposed to be listed. The USB->RS232 converter should be listed if you have installed NI-VISA. You can confirm NI-VISA is installed by expanding the software listing in MAX.

[vbk007]

I am logged in as different user.

It was not showing RS 232/USB communication port in MAX.

I connected the power supply directly to another PC  removing the USB-DB9 adapter.

After this it started showing something at COM1 port.

I tried to use VISA test panel to talk to programmable power supply.

But i am not able to talk to the programmable power supply. (tried to change the baud rate)

What might be the problem?

The specification of power supply are lambada- ZUP120 3.6

Please let me know.

[Dennis_Knutson]

Yes, you have to change the pc's serial port settings to match the instrument's but I'm not sure that is the first thing I would do. I usually use the windows program Hyperterminal to verify com settings and that the cable is correct. There are a lot of things that could be wrong with a serial connection and I think it makes sense to try a program that the instrument vendor is familiar with. Make absolutely clear that the pc's com settings match the instrument's. Then, if you still have problems, try using a different type of cable. If you are using a straight-through cable, switch to a null-modem cable and vice-versa.

I don't know why the USB adapter is not being recognized. I also don't understand your comment about something showing when you used a built-in serial port. Whether you have an instrument connected or not, the com port will be visible in MAX and you have no indication at all that something is connected.

[VYBH]

Hi

I tried to perform hyperterminal test for serial port as per procedure found on ni website.

(http://www.ni.com/support/serial/verhyper.htm)

I am not getting results as per the test. (i.e 2 characters for every one typed)

Even i tried to send commands (given by manufacturer of equipment to be controlled via serial communication)

Those commands are also not working.

I tried with different sets of cables also. But it is not working.

But the instrument in its local mode of operation is working satisfactorily.

Please suggest me other ways if any to make this serial communication work.

Vaibhav

[Dennis_Knutson]

If you cannot get the Hyperterminal test to work, you either have a dead com port on your pc or you did not do the loopback correctly. A correct loopback is simply a short between pins 2 and 3 of the db9 connector. If the loopback is correct, try it with a different port if you have one, with a USB-RS232 converter, or on a second pc.

[vbkhane]

Hi

I am logged in as different user.

Do you asked me to do loopback test or hyperterminal test mentioned in the procedure given on NI website.?

I have tried the hyperteminal test on two differnt machines using different cables. ( This is just to ensure that neither a  cable is faulty nor port is having any problem.)

On both the machines, the test is not working satisfactorily. I am not able to communicate with the equipment via serial communication.

I will try the loopback test by shorting the pins.

Please suggest me any other thing i need to try.

Vaibhav