07-28-2010 10:24 AM
Hi all,
I am not sure if this is the correct board to post in, but it seems related.
I am trying to decide on what type of hardware will work best for controlling the on/off of a relay with a temperature read-out from a K-type thermocouple.
Will a DAQ do this? or should I use a watlow product? Any ideas?
Thanks,
J
07-28-2010 10:43 AM
Here are some additional requirements:
We expect to be using two K-type channels for input.
RS-232 or 485
Relay outputs for high limit (preferably NC, so circuit/power failure prevents beam)
these relay outputs are for 24V, ~10mA - so mechanical relays are probably best.
We want to monitor the temps remotely and be able to reset a high temp alarm trip (over serial)
07-29-2010 03:29 PM
Hi J,
It's not a great idea to make thermocouple readings and control relays serially. Is there another form factor that would work for you? With this application, you would need Digital outputs and Analog inputs with built-in CJC channels. Here is the Data Acquisition product page. You can minimize your search parameters on the left side of the page. For example, you may want to take a look at the compactDAQ platform. With this platform, you can easily combine temperature measurements and digital generations with high-speed USB and NI signal streaming technology. Let me know if you have any specific questions about narrowing down your search.
You can perform instrument control serially. If you had a Watlow device with an RS-232 or 485 connection, you could connect it via RS-232 or 485 and utilize an instrument driver (on ni.com/idnet if it is available). These instrument drivers are free to download and use with LabVIEW or CVI, depending on the specific instrument driver.
Let me know if you need more information.