Filtering on input channels

[LPK]

Hi all,

 

I see it says about the filtering/smoothing/averaging on input channels that there are options that give you no averging, 3-reading, 5-reading or 7-reading averages on input channels, but I was just trying to work out over what kind of timespan this would occur?

 

Do the channels get sampled once every ladder cycle, so the moving average timespan might be (up to) 7 ladder cycles in duration, or would the ladder rungs all be executed and then the inputs sampled (up to) 7 times in succession, making the time span only one ladder cycle? Or do the input channels get sampled on some other kind of demand system?

 

Thank you in advance for clearing this up!

[Eyal Koren]

Hi LPK,

As for all PLC's the input channels are being sampled once per scan (at the beginning of the cycle).

The smoothing feature does not change the system's behavior in any way. all it does is presenting an average value of the input. Consequently, the update frequency for these values will vary according to the smoothing selection.

[LPK]

Thank you for this. It's good to know at what point the inputs are sampled.

 

So if I choose the option that averages 7 readings, that will essentially be the average of the last 7 readings (and thus the last 7 scans)?

[Eyal Koren]

Thank you for this. It's good to know at what point the inputs are sampled.

 

So if I choose the option that averages 7 readings, that will essentially be the average of the last 7 readings (and thus the last 7 scans)?

 

That's correct