S7-1200 HSC Counters att low frequency

[Karsten]

Hello,

I use S7_1200. I Will measure frequency 5-100Hz. Any disadvantages or problems to consider if I use a Hardware HSC set to frequency and 1s?

 

[JRW]

My first thought
Be sure to set the filter on the input very low

 

[Karsten]

Ok. Will the filter be an issue at low frequency? I made a Quick test and seem to read twice the actual frequency 40Hz instead of 20.

 

[JRW]

Probably not

for a test
Even on single phase the freq is doubled?

 

[Karsten]

Works great. Turns out that the sensor gave two pulses/rotation instead of one

 

[drbitboy]

Works great. Turns out that the sensor gave two pulses/rotation instead of one

hahahaha


OT: Many years ago, my brother came to visit (I was in southern tier/finger lakes NY, he lived in GA). Our project was to change the timing belt on my K-car. We carefully set TDC and took the necessary bits apart; we bumped the crankshaft accidentally but put it back (so we thought) using the timing mark. When we put it back together, it would not start, and my brother could see fuel blowing up out of the carburetor while I noticed that the tailpipe was pulling a vacuum; my brother suggested we move the carburetor to the tailpipe.

We went inside for Christmas dinner, which I ate without washing my hands as I was so depressed. I just sat there staring at the floor, and finally the light bulb went on: there were two timing marks; the reason was that way it does not matter to which spark plug cable you hooked a timing light.