Delaying a inductive prox pulse 1

[ccdubs]

Hi all,

I have an application where we sense rotational speed by using an inductive proximity sensor to send pulses to a counter card on a plc every time a gear tooth passes the prox.

The problem I have is that the resolution is a too low and our speed output is not accurate enough. I have recently learned that the PLC can take a second pulse input and can then be set to count leading and lagging edges of both signals, hence 4x the resolution!!!!

To do this though, one pulse input needs to lag the other. This could be done with 2 proxes offset from each other but this is hard to implement. I was wondering if there is a device available on the market that can do this or if it would be simple enough to use a capacitor (and diode?) circuit of some type. The difficulty is that the frequency ranges from 0-1600Hz although most accuracy is needed at 1500Hz which is its normal running frequency.

Thanks for any help.

 

[VEBill]

Soccer is usually 0-0 until someone trips over their shoelace and the other guys (perhaps the weaker team) just happens to score first (a lucky break) and wins 1-0.

Perhaps soccer games should go on for seven days straight so as to build up a slightly higher resolution score - like 5-3.

This nonsense is slightly on-topic because it demonstrates that a longer update cycle time can improve resolution. Of course, the system controller might not like a long update cycle time.

 

[itsmoked]

Absolutely! This is a perfect demonstration of the fine points you put forth in your prior starred post.