1756-HYDO2 as Pressure Transducer SSI?

[Chris Elston 79]

Anyone here ever used a HYD02 for a proportional pressure valve? Sure, it works great with an LVTD and a normal proportional valve to close a position loop, but I would like to use the second axis on this card to close a pressure loop as an axis. I don't think the card will care because it's still controlling a -10 to +10 volt valve, but my only problem is finding an SSI interface pressure transducer feedback sensor. Need an SSI interface with external interrogation and I believe 4 circulations. Anyone ever done this? What pressure transducer did you use?

[Peter Nachtwey 15]

HYD02's have MDT start stop interfaces, not SSI. The M02AS has 2 SSI feedbacks It you can convert the analog to SSI then you should be able to run a pressure PID. You could also put an analog input card in the rack and close the pressure loop in the PLC and use the second control output on the motion controller in direct output mode. This will work if the pressure gain isn't too high.

[Chris Elston 79]

Yes, your right Peter, I posted wrong. MDT start stop interface is what I am looking for. I don't assume they make a MDT start stop pressure transducer. I am using a Balluf Rod BTL5 LVD for the position on the cylinder which is configured MDT. Thanks for catching that....I had SSI in my head because I was playing with an AMCI module. LOL http://www.amci.com/plc-modules/plcmodules...i-interface.asp

[Peter Nachtwey 15]

It isn't necessary to use recirculations any more. Back in the early 90s yes but today we can get 0.0005 inch resolution with just one interrogation because we have 120MHz counters. Using fewer interrogations is necessary because it takes time for the interrogation pulse to travel down the rod. This travel time limits how fast the loop can be closed so it is best to use just one recirculation or interrogation from now on.