Fanuc IC693ALG220 PLC

A limited current input mode is also provided in the module. A jumper is provided on the user terminal connector for each channel, which may be used to connect the internal 250 ohm shunt resistor into the circuit. The shunt resistor effectively provides a –40 to +40 mA current input range. However, the input current should generally not exceed ±20 mA, to avoid self-heating of the input resistor and a corresponding loss of accuracy. A 4 to 20 mA input corresponds to a 1 to 5 volt input to the voltage input module; therefore, the resolution of the 4 to 20 mA input signal is approximately 10 bits binary (1 part in 1024). The resolution can be increased to approximately 11 bits (1 part in 2048) by using a precision 250 ohm resistor in place of the jumper. The resistor causes the voltage input module to see a 4 to 20 mA input as 2 to 10 volts. The main power source for the module is derived from the isolated +24 VDC power supplied by the PLC power supply. This voltage is routed through an inverter/regulator to produce the operating voltages for the module. This module also consumes 27 mA from the +5 VDC output of the PLC power supply. An LED at the top of the module’s faceplate is ON when the module’s power supply is operating. The module provides electrical isolation of externally generated noise between the field wiring and the backplane through optical isolation. To minimize the capacitive loading and noise, all field connections to the module should be wired using a good grade of twisted, shielded instrumentation cable. The shields can be connected to either COM or GND. The COM connection provides access to the common of the analog circuitry in the module. The GND connection provides access to the baseplate (frame ground).

This module can be installed in any I/O slot of a 5 or 10-slot baseplate in a Series 90-30 PLC system.