GE IC670MDL644

Description

Product Overview and Description

The GE IC670MDL644 is a high-density, 120V AC discrete input module belonging to the GE Fanuc Series 90-30 PLC family, or more specifically, its versatile and modular Genius® Distributed I/O system when used with a suitable bus interface unit. This module serves as a critical interface for monitoring the state of field devices like pushbuttons, limit switches, proximity sensors, and selector switches that operate on standard North American line voltage. Designed for space efficiency, the GE IC670MDL644 allows for the connection of up to 32 AC inputs in a single module slot, making it an excellent choice for cost-effective control panel design and remote I/O applications. Its reliable opto-isolated design ensures the PLC’s logic side is protected from voltage spikes and noise inherent in AC power circuits. For engineers expanding or maintaining a system based on this proven platform, the GE IC670MDL644 is a fundamental spare part that enables robust and scalable machine control.

Key Parameters and Specifications

• Manufacturer & Series: General Electric (GE), for the Series 90-30 / Genius® Distributed I/O.
• Module Type: Discrete AC Input Module.
• Input Voltage: 120 Volts AC.
• Input Type: Sinking (current flows into the module when the field device is active).
• Point Density: 32 isolated inputs, organized in groups.
• Nominal Current: Typically 6-10 mA per point at 120V AC.
• On-State Voltage Range: 79-132 VAC for reliable “ON” detection.
• Isolation: 1500 VAC between field side and logic/bus side.
• Response Time: Fast, typically < 25 milliseconds for on/off detection.
• Status Indication: Single LED per group of points (typically 4 or 8 points) indicates power and input status for that group.

Advantages and Distinctive Features

The primary advantage of the GE IC670MDL644 is its high channel density, which maximizes I/O count per rack space or Genius® drop, significantly reducing hardware costs for applications with numerous AC sensing points. A key feature is its robust isolation, which provides excellent immunity to electrical noise and transients common in industrial environments with motors and contactors, protecting the sensitive controller backplane. The module is designed for easy wiring and maintenance, with clear terminal labeling and group status LEDs that simplify troubleshooting. The proven reliability and wide availability of the GE IC670MDL644 make it a trusted component for long-term system support. Its compatibility with the distributed Genius® architecture allows for flexible placement close to field devices, minimizing long wire runs of AC signals and improving overall system reliability and noise immunity.

Application Cases in Key Fields

• Packaging Machinery: Monitoring the status of dozens of safety gate interlocks, product-present sensors, and jam detection switches that are directly powered by 120V AC control circuits.
• Commercial HVAC Systems: Interfacing with pressure switches, flow sensors, and thermostat contacts in large building management systems that utilize 120V AC control voltage.
• Material Transfer Systems: Reading the position of limit switches and paddle wheel sensors on conveyor lines and bucket elevators spread across a large facility, using the Genius® distributed network.
• Automated Assembly Lines: Connecting to manual operator stations with 120V AC selector switches, pushbuttons, and pilot lights on older machinery being integrated into a modern PLC-controlled line.

Comparison with Competing Products

Compared to generic 24V DC input modules, the GE IC670MDL644 is specialized for direct interface with 120V AC field devices, eliminating the need for interposing relays or external voltage converters, which simplifies design and reduces points of failure. Competing AC input modules from other PLC manufacturers (e.g., Allen-Bradley 1756-IA32 or Siemens 6ES7 321-1EL00-0AA0) offer similar functionality but are not electrically or mechanically interchangeable and require their respective proprietary backplanes and configuration software. Within the GE Series 90-30/Genius family, the GE IC670MDL644 is distinct from lower-voltage DC input modules (like the IC670MDL240) or 240V AC input modules, offering an optimized solution for the most common AC control voltage in its market.

Selection Suggestions and Precautions

Selection Suggestions:

1. Select the GE IC670MDL644 specifically for expanding or replacing I/O in an existing GE Series 90-30 PLC or Genius Distributed I/O system where 120V AC field devices are present.
2. It is the ideal choice when a high number of AC inputs need to be monitored from a single location, prioritizing space and cost efficiency.
3. Choose this module when you need to directly interface with legacy machine controls or devices that only provide a 120V AC dry contact output.

Important Precautions:

1. Voltage Compatibility: Confirm your field devices and supply voltage are a stable 120V AC. Applying 240V AC will damage the module.
2. Wiring and Isolation: Adhere strictly to local electrical codes for 120V AC wiring. Ensure proper grounding of the source and use the module’s isolation effectively to prevent ground loops.
3. Sinking Configuration: Wire field devices correctly for a sinking input. The 120V AC source is switched by the field device, and the “hot” side is connected to the module’s common terminal.
4. Group Fusing: Note that the inputs are typically fused in groups (e.g., 4 or 8 points). A fault on one input may disable its entire group. Check the module datasheet for the specific fusing arrangement.
5. Legacy Platform Awareness: The Series 90-30/Genius is a mature platform. Ensure you have compatible configuration hardware and software (e.g., Proficy Machine Edition Logic Developer) for setup. Verify sourcing for genuine or high-quality refurbished units.

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