Micrologix1100 High Speed Inputs

[DaveW]

I have an 1763-L16BWA and I read that the 1st 4 inputs can be used as pulse catch latching or combined as a high speed counter. My question is what is a pulse catch latching and if I want to use the high speed counter for a pulse signal from a flow meter, does this mean I can't use the other 3 inputs?

 

[Nicodemus]

Pulse catching came about as a function of how the Micro's and SLC's scan the I/O. If an input comes in for a very short period of time, the input scan may be too late to catch it. If you configure the point for pulse catching(latching) it will turn on the input on the next scan and keep it high for one scan.

It would appear that if you configure the HSC section of the 1100 that inputs 0-3 are taken up. It allows you to do quadrature, or count with up/down and reset. If you need more I/O, there are a bunch of expansion boards.

http://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1763-rm001_-en-p.pdf