Heater/cooler (Peltier) control in DC (no PWM)

[acanivell]

I am trying to configure a system to control a heater / cooler Peltier element like this:

+/- 5V @ 1.25A

Using direct current (through a PID controller), not a PWM.

I am considering using CRIO or PXI platforms.

- On CRIO I found the motion controller 9505, but I am not sure I can drive it in DC.

- On PXI I found this power supply 4110, but it seems to be an overkill solution (cost-wise) for the problem.

I could even include a small amplifier in the output of an AO module, but I wanted to avoid adding external elements to my NI solution.

Can anybody advice me on the ebest way to make it using CRIO?

[CasperK]

Hello  Acanivell,

You can use the cRIO Real-Time PID control in combination with a analog output module. As you mentioned you will need to include a small amplifier.

More information about the cRIO analog output modules: https://www.ni.com/en-us/shop/category/voltage.html?productId=118154

Regards,

Casper

[acanivell]

However, do I really need the Real Time module to control the CRIO?

My application is just a thermal controller, so real time requirements are not very restrictive. A PID is also easy to program.

[CasperK]

Hello  Acanivell,

Well the best way to do it on an CRIO would be either an analog module in combination with an analog output or using the NI-9505 and PWM.

If you do not need a RT-environment then the only question will be, does it need to run standalone or will a Desktop/Laptop be fine?

In the case of a Laptop/desktop you can use a generic analog output module

in the case of a stand alone application, a simple cRIO controller + chassis will do the trick.

Regards,

Casper

[acanivell]

Thanks for the quick response !

- I do not need standalone operation, so then the RT module would be a waste.

- I do not understand why you say that in case 'standalone' you do not need the analogue output and in case 'desktop' you do.

- Concerning the 9505 motion controller, could you confirm if I can drive it on DC, not using PWM? I found nothing on this in the manuals and tutorials I read.

- Would you then un-recommend the use of the PXI solution compared to CRIO for this application?

Regards

[CasperK · Accepted solution]

I'm sorry for the confusion. What you need for a standalone cRIO-system: 

1. cRIO Chassis

2. cRIO Controller

3. Analog output or a NI-9505

You can control the NI-9505 by a PWM signal, you can't drive just a DC. If I look at your posted requirements, I wouldn't use the CompactRIO.

You can use the PXI-system. Then you will have an industrial pc with again a generic analog output in combination with a amplifier. If you want a clean system, it will be possible to use the programmable power supply. With the PXI-4110 you have the ability to combine channels for higher voltage/current (up to 2 Amp's). A problem could be the speed, please see the manual if the speed is applicable:

https://www.ni.com/docs/en-US/bundle/pxi-4110-specs/page/specs.html

If a clean system is not an issue, I will go for a compactDAQ, USB or PCI-solution. 

Regards Casper

[acanivell]

Thanks again

Well, so far I only looked into CRIO and PXI and now I think that the solutions are clear.

For the other options, I have what would you recommend on compacDAQ, USB, PCI or (maybe?) SCC?

 (I do not know well these platforms)

By the way, the same system must be able to do more things apart from the peltier drive:

- Estimate frequency of an analogue signal (1Khz-100Khz @ 0.1Hz resolution)

- Read temperature from an PT100 (4 wires measurement)

Cheers