Multiple Synchronized Output

[sladed]

Hi,

I have a PXI-6259 card and am using Labview.

I need some advice on the best method of achieving the following requirements:

Drive four pneumatic valve units, each has four solenoid valves. two to apply air and two to vent air.

There are 2 apply profiles and two vent profile - this is for an extended life test

So for one unit the sequence is:

1. Apply profile 1 on sol valve 1 and apply profile 2 on sol valve 2
2. Vent profile 1 on sol valve 1 and vent profile 2 on sol valve 2
3. Apply profile 2 on sol valve 1 and apply profile 1 on sol valve 2
4. Vent profile 2 on sol valve 1 and vent profile 1 on sol valve 2
5. Sample the output every 100th operation (or some arbitrary number)
6. Repeat

I am ok with the above and have put together some rudimentary VIs to load a profile then drive a DIO pin and sample the output - I've attached these.

I would implement the above using a state machine.

I have the interfacing hardware from a previous project

The reason I require some help is that we would like to run four units in parallel with different profile and with offset start times and I am in need of some advice about achieving this

Thanks for any guidance that can be offered.

Dave

[JamesKent]

Hi Dave,

What do you mean by offset start times? Are you setting a single test to run and then automatically want the other tests to run after that or are you setting this application to run at a specific time then walking away and leaving it to its own devices.

It sounds like you need a central controller which is scheduling when the tests need to run and then running them as needed, similar to a queued state machine where you set each of the four units into an idle state, and then send instructions by a queue from a "Master" controller loop to run the tests as needed. It looks like in terms of getting started you have all of the DAQ code you need, now I believe it is more on the architecture side of things.

There is a good article on our website covering the queued state machine, and goes through some the basics and a high level overview of the architecture:

https://decibel.ni.com/content/docs/DOC-32964

Let me know what you think of this and if you have any questions feel free to reply.

Best Regards,

James Kent

[sladed]

Hi James,

Thanks for your reply; I am back on this project now following some delays.

I am struggling with the queued state machine archeture and could use some further guidance please.

Here is a more concise list of requirements:

• 4 UUTs (pneumatic valves A, B, C and D); each UUT has 4 solenoid vales (2 inlet and 2 vent)
• There are 2 profiles (charging and venting) to be applied; the profiles are 20sec in duration
• So Valve A and B run profile 1 and valve C and D profile 2
• Valve A starts at T=0
• Valve B starts at T=2sec
• Valve C starts at T=5sec
• Valve B starts at T=7sec
• When each valve finishes its 20 sec profile it will start its profile again

I have attached a spreadsheet overview of the profile which shows a single shot.

Thanks for any advice you can offer.

Dave