Energy Meters KYZ Pulses

[DanT]

 

 

Looking at an application to monitor  KYZ  Pulses from Energy Meters.

These are Relay Contacts and can pulse upto 10/sec.      ( recommended voltage on the common is  5 VDC    -- an issues with 24 VDC? - from  experience )

Anyone with experience with these:

      Using standard inputs on the PLC  ( Slower, but debounce may be less of an issue)

     Using High Speed inputs where debounce may be an issue.

I am going to do some tests, but other experiences also help.

 

Dan

 

 

[Ausman]

Hi Dan, the first thing my brain asks is what is the length of the pulse?  Does it change with frequency, or is it a fixed number of ms?  So I looked up about KYZ and found this site which explains it well:

http://solidstateinstruments.com/newsletters/kyz-pulses.php

As it appears that the length of pulse does change with frequency on an approx 50/50 relationship, and given the relatively slow nature of the switch, at first I wouldn't even bother and see how it goes only using standard inputs. If bounce does seem to be appearing, still use a standard input but linked to a TE set at 20ms, which should effectively give you a debounce good enough and cover all scenarios. 

Another possible method would be to use something similar to my suggestion below, and progressively tally the result, but it might not be as accurate.  Perhaps read the entire topic.

cheers, Aus

[DanT]

Aus;

 

Thanks for the insights.

 

Dan

[Ausman]

Forgot to say that you can get tiny modules designed for Arduino etc that are effective SSRs for 5V signal work, and can handle 24V into the plc fine.

I "grind" my own versions, based on HSF2/A213DN chip.  I use this to interface directly into signals that normally feed leds, without needing any other power supply, but I think it would work well enough for your situation.  But I can't see that putting 24 instead of 5 on the common is going to be terribly upsetting, given the tiny currents involved.  I feel that it is more likely that the "normal reader" is reckoned by the manufacturer to be 5V based.  Have a play with one of the chips, anyway...they are great and haven't failed me yet.

cheers, Aus

[Ausman]

And an oops to the above.....just realised that you will still need power, from somewhere, into the relay in the first place......my normal chip usage already has power in the form of what is running the leds.  So I'd just go with 24.  But I'd dig up the specifics about the relay on the device, by getting label details and checking specs, just to make sure.

cheers, Aus