How do i hook up a Plug-In Relay to thermocouple?

[nicholas03]

I dont know how to hook my relay to my thermocouple (USB-TC).

[jaced]

Hi,

I would like some more information on what exactly you are trying to do and what specific hardware you are using.

1. What type of Thermocouple will you be using?

2. What NI hardware will this be connecting to.

Because you posted to the Signal Conditioning forum I am assuming you are using a SCC-TC module.If this is the case you need to connect the termocouple to the positive and negative sides of the module then connect the module to the SCC carrier, which will be connected to your data acquisition card.

More information on how this is done can be found in the SCC Quick Start Guide.  For more information specific to the SCC-TC modules please refer to the SCC-TC Series Thermocouple Input Modules User Guide

If you are using the USB-9211, then more information on connecting thermocouples can be found in the USB-9211/9211A User Guide and Specifications

I hope this helps and feel free to post back if my assumptions are incorrect.

[AnalogKid2DigitalMan]

jaced:

I think it's MC's board he's using:

http://www.measurementcomputing.com/cbicatalog/cbiproduct_new.asp?dept_id=414&pf_id=1692

We also need to know the specifications of the relay- what voltage and current does it need to operate. The digital outputs on the MC card are only limited to 2.5mA sink/source

Message Edited by AnalogKid2DigitalMan on 10-11-2007 02:35 PM

[nicholas03]

My relay has 12VDC and 75mA. It is connected that MC board (USB-TC).  I need to know how to send the current into and out of the relay.

[nicholas03]

You were right the output from the USB-TC is 2.5 Volts. I have two problems, I need a relay switch that uses 2.5 volts to switch a 110 current.  I don't know how many amps but I can't imagine that it will be more than one.  The second problem is I don't know how to turn on a the relay switch from the block diagram when the temperature is greater than a number or less than another number.

[nicholas03]

Message Edited by nicholas03 on 10-14-2007 07:56 PM

[jaced]

As I understand it, you have a USB-TC which is reading a temperature reading and you wish to take this reading and use it to control a relay. The confusion is do you have the relay or are you asking for recommendations? If you have the relay you should be able to connect it to one of the digital output lines on your USB-TC device which will be controlled through LabVIEW to go high or low based on the temperature reading. I am not familiar with your USB-TC device, but from what you said, seems like you want to connect a relay to digital lines... here is more information on how to do it

Problem Controlling Relays with Digital Lines

Common Hardware Connections for Digital I/O and Counter/Timer Boards

With regards to how to accomplish this task in LabVIEW please refer back to your original post on this forum.

 One suggestion that I do have is to use a case structure with ranges in each case as follows.

0..70 relay is off.

71..80 do nothing, if the hardware operates similar to NI hardware it will hold the last written value.

81..100 relay is on.

The input to the selector terminal will be the temperature value from your acquisition.

[nicholas03]

Would the USB-ERB08 board from MCC be able to run this fan? Or something similar to it.

[jaced]

Hi,

I am not familiar with MCC hardware perhaps another user is and can answer your question. I would suggest that the best place for an answer to your question is Measurement Computing technical support. The link to their technical support is below.

http://www.measurementcomputing.com/tech.html

It is also very difficult to determine if the device would power your fan based on a picture alone. From what I can tell the USB-ERB08 is able to supply 4A,found at
http://www.measurementcomputing.com/usb-erb08specs.html

Again I would recommend that you contact MCC for more information on their devices.  

[nicholas03]

I did contact them through the forum but have not been answered yet.  Do i need to tell you the voltage and power of the fan?