User manual

Hardware Description

2.1.4 Measurement of Current Signals

The circuit diagrams in the schematics section of Appendix A. “Schematics and

Layouts”, provide details on the resistor values used for the current measurement

circuit. Table 2-9 provides a quick reference to resistor values while measuring the

current signals. The output of Current Transformers (CTs) can be connected to the

input connector pins.

When measuring a current signal on the input terminals of channels CH0 and CH1,

refer to Table 2-10 and Table 2-11. These tables provide the configuration of jumpers,

along with the amplitude of the voltage available at the various points.

TABLE 2-9: RESISTORS FOR LOW VOLTAGE MEASUREMENT

R26 and R28 0.063

R27 and R29 0.063

R34 and R36 1

R33 and R35 1

R37 and R39 1

R38 and R40 1

TABLE 2-10: JUMPER SETTINGS FOR CURRENT MEASUREMENT ON CH0

CH0 Jumper Position ADC

Remark

CT Primary

Current

(Irms-A)

JP1 JP2 JP3 JP4

ADC I/P

(Vrms)

ADC I/P

(Vpeak)

0.1 Short 2-3 Open Short Open 0.00063 0.00089 Internal Gain of 2 can be used for

better resolution

0.5 Short 2-3 Open Short Open 0.00315 0.00445

1 Short 2-3 Open Short Open 0.0063 0.00891

10 Short 2-3 Open Short Open 0.063 0.08910

20 Short 2-3 Open Short Open 0.126 0.17819

30 Short 2-3 Open Short Open 0.189 0.26729 Max Differential ADC I/P is 0.5V