Micrologix 1000 high speed counter interrupt: need to turn off output

Hi All,

I'm new to the site. Lots of useful info on here...

I am implementing a flowmeter-based dispense system. The controller I'm using for testing is a AB Micrologix1000. The objective sequence is such:
1) start button fires sequence
2) Sol valve turns on, allowing liquid to flow
3) HSC counts up to preset
4) interrupt fires, output to sol valve is turned off

I would like the valve to turn off immediately when the interrupt occurs... I have tried using a OTL in the main program and OTU in the interrupt sub... the output doesn't turn off...

Any ideas for making this happen? Also, do I need to use a IOM to make it happen right away?

Thanks in advance!

Adam S

Haha, OK so I got it figured out right after I posted that... did a one shot to the OTL of the sol valve. It was blocking the output from being unlatched as its conditions were still true.

Nonetheless, will using a IOM to turn it off decrease the lag time to turn off the valve?

THanks!

Adam S

Ha. Okay, got everything working now. IOM is pretty cool... I was just using it wrong before.

I think this system should work very well now. Let me know if anyone else out there is working on a similar application.

What type of response time do you need? I'm not a fan of using the IOM

Adam i am only fairly new to the site too but i am doing something very similiar to you, flowmeter based dispensing system but i am doing it with a micrologix 1200. Just wondering if you could help me with an example of code using the high speed counter as i haven't worked how to use it yet.

Glenn

Noble said:

Adam i am only fairly new to the site too but i am doing something very similiar to you, flowmeter based dispensing system but i am doing it with a micrologix 1200. Just wondering if you could help me with an example of code using the high speed counter as i haven't worked how to use it yet.

Glenn

Click to expand...

While you are waiting for Adam, take a look at link below for an example code from TWControls. I'm sure he will be back to explain more.


http://forums.mrplc.com/index.php?autocom=downloads&showfile=577

The sample code Mickey posted would work well with a mode of 0 in the HSC and your flow meter connected input 0

Or you could go with an EII and a simple ADD statement in your routine. This has been a popular subject this week. I'll see if I can make a sample program for this

Here's my code... may not be of help to you though, as this program is written for a MLX1000. Configuration and instructions are different on the 1200.

This is actually just a test program for a proto system I'm building. The production machine will use a MLX1400 and have 4 flowmeters running on it.

Let me know if you have any questions/suggestions.

Best.

TWControls, why are you not a fan? Is there problems with IOM? What are the alternatives? I'm basically looking for the fastest possible response time, as the lag turning the valve off seems to be the major source of inaccuracy and variation. Thanks in advance for your response.