Infinite Peripherals SCOM-100 - Manual (Page 7)

SCOM-100, User guide 7
Voltage Current Mode
250VAC 10A
AC1
250VAC 1A AC2,3
150VDC 0.5A DC
It is recommended to use external power relays to drive inductive or capacitive loads
demanding more than 0.5A.
2.4 Analog inputs
SCOM-100 has 2 built in analog inputs (AI1, AI2). A1 is designed for voltage input and
A2 for current input.
2.4.1 Analog input 1
Analog input 1 is a voltage input with two wiring options.
Wiring option: A1A
The input voltage range for this wiring option is 0-1VDC. The input resistance is 2K.
The input voltage range is converted internally to a digital raw range of 0-4095.
The circuit displayed on the left side of the page uses a monolithic semiconductor
sensor (AD592) for temperature measurement. This sensor acts as a high impedance
temperature dependent current source of 1µA/K. The nominal current output is 298µA
at 25°C. The voltage drop on the analog input resistor (2K) is 496mV at -25°C and
756mV at 105°C. The SCOM-100 power supply (Vcc) can be used for the sensor’s
excitation.
The circuit displayed on the center uses an external shunt resistor (51 Ω) wired parallel
to the input in order to measure current signals (e.g. 0-20/4-20mA).