Is there a way to prgram an arc detect?

[Mken43]

We are going to switch an electrolytic coatings stripper from Labview to a plc. We need tomonitor the voltage and current readings from the rectifier. Does anyone know a way to program an arc detect? For instance if the voltage or amperage rises to fast in a given amount of time.

 

[Steve Bailey]

I've done it for an electrostatic precipitator.

You have to be careful to match the needs of your system to the capabilities of the PLC. How quickly do you need to react? Read the specs on your PLC's analog inputs. The analog to digital conversion takes time. The higher the resolution, the more time it takes. If the PLC's scan time is faster than the time for the A/D conversion, you won't get fresh data every PLC scan. Also, there may be filtering built into the analog module.

 

[jdbrandt]

Couldn't you use a 'jam relay', like they use on punch presses?
Its basically a relay that is very sensitive to the di/dT of current, and
can shut off a starter/contactor in a very short time.
The last one I used was from the Far East, and I don't remember the name.
Just think of it like an electronic shear pin.

 

[CeCo3]

Why depart from LabView? Have you considered NI Compact FieldPoint (http://www.ni.com/pac/cfp.htm) or CompactRIO ($$)? Both are much faster than a typical PLC and you are already on a LabView platform. Just curious.



CeCo3

 

[Sliver]

The GE SQ300 is used by us to monitor and control sparking in electrostatic preciptitators as Steve mentioned earlier.

It looks like a very similar application.

Brian.