Two Simultaneous PID servo control loops @6Hz usin

[pallen]

I have some questions about possible hardware limitations on system

we're currently building.

We're using a Dell Precision 370 and 2 NI6024E cards to control two

hydraulic cylinders. Can LabView running on a PC handle two

simultaneous PID loops at 6Hz? (Feedback for the PID coming from a strain guage)

While we're still fine tuning things and it looks like it may work, there are concerns that we could run up against hardware limitation that will cost us time we can't afford on this project.

Any thoughts appreciated.

[Michael Aivaliotis]

PID control on a PC? Hmm. If it was more than 5 years ago I'd say sure, give it a go. However now with the availability of the LabVIEW RT software module and the RT targets, why go PC? The frequency is low enough to be run on a compact fieldpoint module. You will not get determinism on the windows platform. How critical is this control? What happens if you lose control? Do bad things happen? Do people get hurt?

[pallen]

"PID control on a PC? Hmm. If it was more than 5 years ago I'd say sure, give it a go. However now with the availability of the LabVIEW RT software module and the RT targets, why go PC?"

I've not been directly involved in this project up to this point, so I can't say specifically why PC control was chosen for it.

"How critical is this control?"

This particular application controls a hydraulic cylinder that runs a repetitive stress test. The control is critical to accuracy of the test.

One unit at a time is tested in a fully caged enclosure. Units under test are expected to destructively fail after X number of cycles. The cylinder is large enough to snap the DUT in half in a couple of seconds if something goes really wrong.

The programmer on the project was having some initial difficulty and I thought it might be a good idea to ask some gurus if we were up against a hard limit of the hardware. :worship:

[happl_scott]

"PID control on a PC? Hmm. If it was more than 5 years ago I'd say sure, give it a go. However now with the availability of the LabVIEW RT software module and the RT targets, why go PC?"

I've not been directly involved in this project up to this point, so I can't say specifically why PC control was chosen for it. 

"How critical is this control?"

This particular application controls a hydraulic cylinder that runs a repetitive stress test.  The control is critical to accuracy of the test. 

One unit at a time is tested in a fully caged enclosure.  Units under test are expected to destructively fail after X number of cycles.  The cylinder is large enough to snap the DUT in half in a couple of seconds if something goes really wrong.

The programmer on the project was having some initial difficulty and I thought it might be a good idea to ask some gurus if we were up against a hard limit of the hardware.  :worship:

2584[/snapback]

How did you go with this I am interested in using Labview as a basis for Hydraulic control for fatigue testing. Cycles are slower at around 1-2 Hz, but eventually would like to feed back realtime test data measured off a test track.