hardware for hydraulic actuator

[WyoEng]

Howdy from Wyoming!

I'm working on rounding up a list of hardware components needed to build a full hydraulic actuator controller.  The hydraulic actuator is an Instron 1332, which is currently working just fine.  The current controller we have is an MTS TestStar IIs, and while it is working fine as well right now, we need to upgrade to a different controller, as the only software that will run that controller can only be used on Windows XP or older operating systems.

So, I know a few of the kinds of things I'll need to replace the current controller, but no specifics, as in, just what NI hardware will work for that task.  I need:

Something to send a 25-50mA signal to an acutator servovalve

Something to read an LVDT.  I know of the SCXI 1540 module that NI has, but is there anything newer that could match the same platform as the other hardware for the controller?

Something to read a load cell--I know of CDaq options, such as the NI 9237, but is this ideal for a controller system?

Hardware to control a solenoid valve.

Hardware to control a safetly soldnoid valve.

Hardware to control switches triggered by hydraulic pressure readings.

I was told by MTS that our current system is digital, and so I'm wondering if we can make our new system digital and if that would help make the controller to react faster to commands compared to analog.

Really, I am very unfamiliar with building a control system for a hydraulic actuator, so any advice would be greatly appreciated.

[AndyClegg]

First decide if you are happy with control running in PC with appropriate IO modules, or if you want control to run on true real-time target (like cRIO) with PC simply acting as interface to controller (permanent or temporary). This depends on what you are trying to do with the control - and speed of response and the type of control - on/off control or PID control ?

You should be able to find interface modules to read or output signals for whichever route you go... just be sure to have complete specs for IO (current draw requirements, etc) and control (resolution, sample rates etc). We've used NI 9237 for interfacing to load cells for force control in hydraulic applications using cRIO. One thing to note is that the whilst it can be configured to produce different excitation voltages - the signal from the load cell is in fact in units of mv/V (i.e. independent of load cell) rather than just in mV - which isn't made very clear in documentation.

You can make analogue very fast responding, as you can make digital fast responding if everything specified properly - do remember that just because you select a fast sample time doesn't make your system fast - that depends on the control strategy and what you are trying to control as there will be fundamental limitations. Select your sample time to be at least 10x faster than the fastest signal you want to control.

[tdt1967]

What is the status of this project? I have an instron 1350 and I am intersted in making it work with NI controls.