SCOM-100, User guide 12
The circuit displayed on the center uses an external
shunt resistor (~51.3 Ω) wired parallel to the input in
order to measure current signals (e.g. 0-20/4-20mA).
The circuit displayed on the right side of the page uses
an external resistor (Rx) to measure DC voltage (Vx). Rx
and Rin (2K) form a voltage divider. The following table
illustrates the applicable resistor Rx values for different
DC voltages:
Vx Rx Vin
0..1V 0 0 -1V
0..5V 8K, 1/4W 0 -1V
0..30V 58K, 1/4W 0 -1V
0..60V 118K, 1/4W 0 -1V
0..100V 198K, 1/4W 0 -1V
Note: In case of low voltage measurements, use short
and shielded wiring to avoid 50Hz (60Hz) line noise
inteference.