Measurement Filtering

Introduction

The system uses first order filtering. The filtering coefficient can be modified from a programming console or via the program.

Mathematical Formula

The mathematical formula used is as follows:

where:

α = efficiency of the filter,

Mesf(n) = measurement filtered at moment n,

Mesf(n-1) = measurement filtered at moment n-1,

Valg(n) = gross value at moment n.

On configuration, you can select the filtering value from a choice of 7 values.

Values for the Module TBX AES 400

The filtering values are as follows, and depend on mains voltage:

Effectiveness	Value	Corresponding α	Rejection time constant at 50 Hz	Rejection time constant at 60 Hz
No filtering	0	0	0	0
Low filtering	1 2	0.750 0.875	1.6 s 3.2 s	1.4s 2.7s
Medium filtering	3 4	0.937 0.969	6.4 s 12.8 s	5.4 s 10.8 s
High filtering	5 6	0.984 0.992	25.6 s 51.2 s	21.1 s 43.5 s