AN3254

Converting readings into measured values

Doc ID 17783 Rev 1

19/24

Each block of the path contributes to the signal processing with the parameters shown

below.

Table 3 shows the variable parameters that must be considered as inputs for the following

calculation, while Table 4 shows the device internal constant parameters.

x_i can be one of the current readings in the registers from DMR to DEN (iR MOM, iS MOM,

etc., sI RMS, iR RMS, iS RMS, etc.), and x_u can be one of the voltage readings in the

registers from PRD to DEN (DC uN, uR MOM, uS MOM, etc., uR RMS, uS RMS, etc.).

x_period is the 12 bits value in the PRD register.

Figure 9.

Current conditioning

Figure 10.

Current signal path

Table 3.

Input parameters

Parameter

Meaning

R1, R2

Voltage Divider Resistors Value [Ohm]

Ks

Current Sensor Sensitivity Value [V/A]

x_i

Current Register Value expressed as decimal

x_u

Voltage Register Value expressed as decimal

x_period

Period Register Value expressed as decimal

Ai

Current Channel Gain