2.1.1 Voltage Dividers Adjustment

The signal applied to the voltage input connectors of the demo board is reduced by means of resistor voltage dividers. All the evaluation boards use the same divider configuration, so the divider ratio is the same for all the boards and all the phases. The default value is 1651:1, allowing voltage inputs up to 291 Vrms (Vmax). The maximum input voltage supported can be calculated according to the following equation:

Where:

• Vpk is the peak voltage at the voltage channels metrology inputs of the metering unit. Its typical maximum value is 0.25V.
• KVx is the voltage divider ratio. The default value is 1651.

The metrology voltage divider ratio values are configured into the metrology library by means of the control registers, K_Vx. Refer to the “PIC32CXMTx Metrology User Guide”, which includes configuration examples. The K_Vx values can be read using the terminal command DCR and written using the command DCW (see 2.5 Demo Meter Application Commands).