IC694ALG221 GE Fanuc PACSystems RX3i 4-Channel Analog Input Module

IC694ALG221 Emerson PACSystems RX3i Analog Input Module

The IC694ALG221 is a high-accuracy 4-channel analog input module engineered for the Emerson GE Fanuc PACSystems RX3i controller platform.

This module converts process signals into 12-bit digital values for real-time closed-loop automation tasks.

It accepts standard process loop currents including 0-20 mA and 4-20 mA configurations.

System integrators rely on its fast 2 ms update rate for time-critical industrial monitoring applications.

Technical Parameter Breakdown

1. General Architecture & System Details

Brand: Emerson / GE Fanuc

Series: PACSystems RX3i

Part Number: IC694ALG221

Module Type: Analog Current Input Module

Number of Inputs: 4 single-ended channels

Connector Type: Removable 20-screw Terminal Block (Included)

2. Input Signal & Conversion Characteristics

Input Ranges: 0 to 20 mA, 4 to 20 mA (Jumper Configurable)

Resolution: 12-bit (4 µA/bit at 4-20 mA; 5 µA/bit at 0-20 mA)

Absolute Accuracy: ±0.1% full scale + 0.1% reading

Linearity: Less than 1 LSB

Channel Update Rate: 2 ms (0.5 ms per channel scan speed)

Input Impedance: 250 ohms

Input Filter Cutoff: 325 Hz

3. Electrical & Isolation Parameters

Backplane Current Draw: 25 mA @ 5 VDC; 100 mA @ 24 VDC (Isolated)

Common Mode Voltage: 200 VAC peak

Isolation Rating: 250 VAC continuous / 1500 VAC for 1 minute (field-to-backplane)

Compatible Equipment & Application Scenarios

The IC694ALG221 interface connects directly with all PACSystems RX3i CPUs.

It processes input signals from pressure transmitters, flow meters, and temperature signal conditioners.

Typical applications include continuous level monitoring in chemical storage tanks.

It provides analog feed feedback for PID control loops in water treatment systems.

It monitors loop currents in oil and gas valve positioner feedback assemblies.

Installation Guidelines & Diagnostic Capabilities

Mount the module into any standard slot of an active PACSystems RX3i backplane.

Hardware jumpers configure channels 1-2 and channels 3-4 for current selection.

A green "MODULE OK" LED displays module power state and internal micro-controller readiness.

The module detects missing backplane power or improper seating during power-up routines.

Warning: This unit does not support hot-swapping; power down the rack before insertion or removal to prevent physical damage.

Commercial Logistics & Warranty Policy

Global PLC Spare HUB's Insight & Field Experience

In municipal water facilities, signal noise often distorts sensitive instrument lines.

Our field engineers regularly deploy the IC694ALG221 to stabilize noisy flow meter loops.

The internal 325 Hz hardware filter rejects high-frequency noise generated by nearby variable frequency drives.

During one retrofit, a customer reported erratic current readings across long field cable runs.

Replacing an unisolated card with the IC694ALG221 eliminated ground loops due to its 250 VAC optical isolation.

Always double-check jumper placements before wiring active 4-20 mA loops to avoid blown sense resistors.

Selection & Purchasing Guidance

Select this module when your control scheme requires 4 or fewer analog current inputs.

Verify that your field devices provide 0-20 mA or 4-20 mA current outputs.

If your instrumentation requires voltage signals (0-10 V), choose a dedicated voltage card instead.

Ensure your power supply budget accounts for the required 100 mA current draw at 24 VDC.

Frequently Asked Questions (FAQ)

Question: Can I safely insert or extract the IC694ALG221 while the rack power is active?

Answer: No, hot-swapping is strictly unsupported for this specific module. Removing or inserting this unit while power is applied can damage hardware components or injure personnel.

Question: How are the input ranges configured on this 4-channel module?

Answer: Ranges are set using physical hardware jumpers. One jumper configures channels 1 and 2, while a second jumper sets channels 3 and 4 for 0-20 mA or 4-20 mA operation.

Question: What should I check if the "Module OK" LED fails to illuminate green?

Answer: Confirm that the module is firmly seated into the backplane slot and verify that the 24 VDC isolated supply and 5 VDC backplane supply voltages are within specified tolerances.

Question: Field Experience: Why am I reading 0 mA on my software channel despite having an active field sensor?

Answer: Check range jumper settings and field terminal polarities. Incorrect jumper placement or reversed field loop wiring will block signal processing and report 0 mA counts.

Question: Field Experience: Can I connect voltage sources directly to this module?

Answer: No, this card is designed strictly for current inputs. Connecting raw voltage sources without external conversion resistors can burn out the internal 250-ohm input resistors.

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