06-19-2014 07:46 AM
I currently have a cDAQ chassis and I am trying to do some PID control with it. I just want to be sure I purchase the correct modules, though. At the moment I have a thermocouple input and a 4-20mA output.
My own digging has led me to believe I want a NI9214 (to scale up) and a NI 9265. I was just wondering if the cDAQ-9178 would be physically capable of running the PID loop.
06-20-2014 09:43 AM
The cDAQ-9178 does not possess internal programmable memory. The chassis only sends the acquired data to the computer using the USB port, so, in reality the PID will execute in your PC.
The performance of the PID will be bounded to your system specification and the amount of determinism you can achieve in this PC. There are a couple articles online taking about the performance in Real-Time operative systems that may work as a reference point:
1. Benchmarking Single-Point Performance on National Instruments Real-Time Hardware
2. Benchmarking a Typical Control Application using LabVIEW Real-Time & NI-DAQmx
3. Improving PID Controller Performance
I hope this helps