Need help with making 'integrator' function block?

[IanJohnston]

Hi all,

This is tearing my hair out!

Mitsubishi Q series PLC, Mits GX IEC Developer.

I have an analogue input I'd like to have 'damped'. Not simply turning up the averaging but more like an Integrator function block....thus the response of the final value is still fast, but on a big input value change, instead of jumping directly to the new value it will 'ramp' to get there.

It seems there isn't a built in Function or block I can use, and I've tried building my own using a 'ramp' block etc.....but it just don't work quite right.....requires too much stuff around it to control.

Any ideas, sample code etc etc.....highly appreciated.

Ian.

 

[Tom Jenkins]

Try this link: http://forum1.automationdirect.com/board/Forum1/HTML/000368.html

 

[IanJohnston]

Thanks Tom, I'll give it a go.

Ian.

 

[rytko]

Try this:

http://www.plctalk.net/qanda/showthread.php?s=&threadid=1130

I used it to make a low pass filter for an analog input in a GE 90-30 PLC with an adjustable time constant. It worked very well.

 

[IanJohnston]

Hi,

Thanks, I'll look at that low pass filter......

.....in the meantime, Tom's equation works pretty good on GX IEC Developer. It near as damn it works like an Integrator which is what I originally wanted.

Ian.