GE Fanuc IC693MDL940 Series 90-30 Relay Output Module 2A Form C

Product Overview

The General Electric IC693MDL940 serves as a high-capacity Relay Output Module within the Series 90-30 Programmable Logic Controller (PLC) ecosystem. This module provides 16 isolated output points, utilizing "Form C" (Normally Open/Normally Closed) relay logic to manage diverse load types. Engineers deploy this module to bridge the gap between low-voltage PLC logic and high-power field devices such as motor starters, solenoids, and indicators. By offering physical isolation between the internal PLC bus and external field circuits, the IC693MDL940 protects sensitive control electronics from voltage spikes and electrical noise. Its robust mechanical relay architecture ensures dependable switching performance in demanding industrial environments, including water treatment facilities and assembly power distribution.

Core Technical Advantages

High-Versatility Form C Logic

Unlike standard modules that only offer Normally Open contacts, the IC693MDL940 features 16 Form C relays. This provides both a Normally Open (NO) and a Normally Closed (NC) contact for every output point, allowing for complex interlocking and fail-safe wiring configurations without additional external relays.

Superior Electrical Isolation

The module architecture implements a 1500V RMS isolation barrier between the field-side wiring and the backplane logic. This galvanically isolated design prevents ground loops and ensures that a catastrophic failure in the field equipment does not compromise the CPU or other I/O modules in the rack.

Flexible Voltage Compatibility

The mechanical nature of the contacts allows this module to switch both AC and DC power sources. It operates effectively across a wide spectrum, from low-level 5V DC signals up to 125V DC or 240V AC, providing a universal solution for mixed-voltage control cabinets.

Technical Specifications

Installation & Maintenance Guide

Terminal Block Wiring

Users must remove the front hinged terminal block to facilitate easy wiring. Ensure that all field wires follow the designated pinout for NO, NC, and Common terminals. Tighten screw terminals to the specified torque to prevent arcing under high-vibration conditions.

Current Limiting Precautions

While each point supports 2A, the total module current must not exceed 4 Amps. Engineers must distribute high-current loads across multiple modules or use external interposing relays if the cumulative current draw threatens to exceed the backplane power limits.

Arc Suppression

When switching inductive loads (solenoids, contactors), install external suppression circuits—such as RC snubbers for AC or flyback diodes for DC—across the load. This practice extends the mechanical life of the relay contacts by minimizing arcing during circuit interruption.

Engineering Advantages

The IC693MDL940 stands out for its longevity and "plug-and-play" integration within the GE Fanuc Series 90-30 platform. The module supports hot-insertion into any available I/O slot (provided the rack power is cycled per safety protocols), making it an ideal choice for system expansions. Its internal logic utilizes the +24V relay power bus from the PLC power supply, ensuring that the relay coils actuate firmly even when the control logic is under heavy processing load. The visible LED array provides immediate diagnostic feedback, allowing maintenance teams to verify output status at a glance during troubleshooting.

Technical FAQs

Q1: Does the IC693MDL940 require an external power supply for the relays?

A1: The module draws its coil power from the +24V DC relay power bus provided by the Series 90-30 power supply through the backplane. However, the power switched through the contacts must come from an external field source.

Q2: Can I mix AC and DC voltages on the same module?

A2: Yes. Because each relay point is mechanically isolated, you can switch different voltages and polarities across different points, provided you adhere to the individual point voltage ratings.

Q3: What is the difference between this and the MDL930 module?

A3: The MDL930 typically provides "Form A" (Normally Open) contacts, whereas the MDL940 provides "Form C" (Changeover) contacts, offering significantly more flexibility for complex wiring schemes.

Q4: How should I respond if an output LED is ON but the field device is OFF?

A4: This indicates a possible blown field fuse, a broken field wire, or worn-out relay contacts. Check the continuity across the Common and NO terminals while the LED is energized.