FUJI FEH323 PLC Module

This PLC module provides analog input capability for FUJI electric automation systems. It converts field sensor signals into digital values for processing. Therefore, it enables precise monitoring of temperature, pressure, and flow in industrial applications.

Physical and Analog Specifications

The FUJI FEH323 measures 12.5 cm in length and 9.0 cm in width. Moreover, its module weight equals approximately 0.32 kg for DIN rail mounting. A single 18-pin removable terminal block handles all field wiring connections. Additionally, this module contains four independent analog input channels.

Parameter	Specification
Brand	FUJI Electric
Full Model	FEH323
Category	PLC Module (Analog Input)
Dimensions (L x W x H)	12.5 cm x 9.0 cm x 5.5 cm (4.92″ x 3.54″ x 2.17″)
Module Weight	0.32 kg (0.71 lbs)
Primary Interface	1 x 18-pin Removable Screw Terminal Block
Backplane Interface	1 x 32-pin Male Connector (FUJI Rack)
Operating Voltage	24 VDC from Backplane (19.2 to 28.8 VDC)
Power Consumption	3.0 W (Typical)
Analog Input Channels	4 Differential Channels
Input Signal Range (Voltage)	0 to +10 VDC, -10 to +10 VDC
Input Signal Range (Current)	0 to 20 mA, 4 to 20 mA (with External Resistor)
Resolution	12 Bits (0 to 4095 Counts)
Conversion Type	Successive Approximation (SAR)
Conversion Speed	2 ms per Channel (8 ms for All 4 Channels)
Input Impedance (Voltage)	1 MΩ (Typical)
Input Impedance (Current)	250 Ω (with External Resistor)
Absolute Accuracy	±0.5% of Full Scale at 25°C
Absolute Accuracy Drift	±0.02% per °C
Common Mode Rejection	80 dB (50/60 Hz)
Normal Mode Rejection	60 dB (50/60 Hz)
On-Board Components	1 ADC Chip + 4 Signal Conditioning Circuits + 4 Protection Diodes + 1 Voltage Reference IC + 1 EMI Filter + 1 Voltage Regulator
Energy Storage	2 x 100 µF Electrolytic Capacitors (35V) + 2 x 10 µF Tantalum (25V)
Isolation Rating	1500 Vrms (Field to Logic)
Common Mode Range	±10 VDC Maximum
Operating Temperature	0°C to +55°C (32°F to 131°F)
Mounting Type	DIN Rail or FUJI PLC Rack
Status Indicators	1 Green LED (Power) + 1 Green LED (Active) + 1 Red LED (Fault) + 4 Green LEDs (Channel Activity)

Input Channel Features and Signal Conditioning

The FUJI FEH323 accepts four differential analog input signals for better noise rejection. Specifically, each channel includes a dedicated signal conditioning circuit for accurate conversion. In addition, the input impedance of 1 MΩ minimally loads voltage-type sensors. Moreover, the 12-bit resolution provides 4096 discrete steps for each input range. Consequently, this module delivers precise measurement for industrial process variables.

Voltage and Current Input Flexibility

This analog module accepts either voltage or current signals from field transmitters. For instance, the 0 to 10 VDC range suits standard pressure and level sensors. In addition, the 4 to 20 mA range works with two-wire loop-powered transmitters. Furthermore, you need only an external 250 ohm resistor for current mode. Thus, this module handles a wide variety of industrial analog sensors.

Energy Storage and Signal Integrity

This PLC module stores energy using four onboard capacitors for power filtering. Specifically, two electrolytic capacitors smooth the 24 VDC supply for stable ADC operation. In addition, two tantalum capacitors provide high-frequency noise suppression for analog circuits. Furthermore, these capacitors maintain conversion accuracy during brief power interruptions. Therefore, the FUJI FEH323 rejects electrical noise from factory environments effectively.

Installation and Diagnostic Indicators

Seven LED indicators provide operational status at a glance on this module. First, a green Power LED lights when the 24 VDC backplane supply is present. Second, a green Active LED flashes during normal analog conversion operation. Third, a red Fault LED indicates hardware errors or out-of-range signals. Additionally, four green Channel Activity LEDs illuminate when each channel receives a valid signal. Thus, you can diagnose analog input status instantly without external tools.