Filter Feature on CompactLogix Module

[Abn]

Hi,

What are the filters for in the configuration tab?

Regards

 

[daba]

Hi,

What are the filters for in the configuration tab?

Regards

Well my guess is that it would help if you told us which CompactLogix module you are asking about ....

 

[Abn]

Well my guess is that it would help if you told us which CompactLogix module you are asking about ....

It's a IF8 analog input.
In the module configuration window, you can select the type of signal
Vol, ma, etc. There is a filter option, not sure how exactly it works.

 

[daba]

The filter is a "notch" filter, which attenuates signals at a specific frequency. It is used to filter out any pickup from the "mains" alternating current.

It defaults to 60 Hz, because Allen-Bradley is an American company, but it has options for other mains frequencies. Over here in the UK our mains frequency is 50 Hz, so we are constantly changing from the default of 60 Hz when we commission new modules.

Well that explains, two of the values you can choose. I don't know why you would need a 10 Hz notch filter, but the larger ones, 250 and 500 might have something to do with submarines, or aeroplanes, as at higher frequencies less copper is needed in coils to create the same reluctance.

 

[daba]

Almost without exception 60 and 50 are for domestic supplies.

Some countries' Rail Electrification systems use 16.6666 (16.7) Hz, and some use 25. There's a couple that use 40, and one that has a variable frequency of 38 to 48.

Good article on it all over at Wiki