compactRIO, FPGA, RTOS

[felipetortato]

Hi, I've never worked with cRIO before, and I need to make a program that has an user interface, controls the temperature of a hothouse, turns it on and off and shows data from the hothouse on the interface.

I don't know if I need to program the FPGA and the RTOS in order to do that, or if I can program only de RTOS.

In that case, I don't know which labview mode is the best to use (Real-time, scan or FPGA). Neither the best way to communicate (message, current value or stream).

Also, which design pattern is best for this applicantion?

Thanks.

[crossrulz]

Dealing with thermocouplers, I doubt we are dealing with anything faster than 10ms/sample.  Therefore, use the  scan engine mode for your cRIO.

A simple control loop and an HMI communication loop should be all you will need here with the RT system.

I would use Network Streams to send the data back to your user interface computer for logging purposes.

If you want a good night's sleep, go and start reading the NI LabVIEW for CompactRIO Developer's Guide.  There is a ton a really good information in there.

[felipetortato]

It's not only one thermocouple. Actually there are 28 hothouses with four thermocouples each. They have different times to start and stop acquiring. There are anyway I can communicate directly with the thermocouple?

[crossrulz]

I would still just use the Scan Engine.  The nice thing with using the scan engine for thermocouples is that it already does all of the conversions to temperature for you instead of making you convert the raw voltage into a temperature in the FPGA or RT.