GE IC693MDL940 PLC Relay Output Module – Series 90-30

GE IC693MDL940 – 16-Point Isolated Relay Output Module for Series 90-30 Discrete Control Loops

The IC693MDL940 occupies a single slot in any GE Series 90-30 rack and delivers 16 independently isolated relay contact outputs rated at 2 A continuous per point. Unlike transistor-output modules that are constrained to DC loads and a fixed polarity, the IC693MDL940’s dry-contact relay architecture allows each output to switch 120 VAC, 240 VAC, or 24 VDC loads from a single module without external interface relays. This characteristic makes it the default selection for motor-starter coil control, solenoid valve actuation, and pilot-light circuits where load voltage varies across the panel.

Within the Series 90-30 control loop, the module sits at the final execution boundary: the CPU asserts an output coil state in the %Q reference table, the backplane bus transfers that state to the module’s output latch on each I/O scan, and the relay contact closes or opens within the module’s specified operate time. The deterministic scan-to-contact latency is bounded by the CPU’s I/O scan period plus the relay operate time (≤10 ms typical), which is acceptable for all discrete actuator classes that do not require sub-millisecond switching.

The module’s relay contact isolation architecture separates the field-side wiring from the backplane logic bus at two levels: the coil drive circuit uses optical coupling between the backplane logic and the relay coil, and the relay contact itself provides galvanic isolation between the field load and all internal electronics. This two-stage isolation boundary limits the propagation of field-side transients—inductive kickback from contactor coils, capacitive coupling from long cable runs—into the CPU’s memory bus, which is a common root cause of spurious program faults in relay-heavy panels.

Each of the 16 output points is individually fused at the field wiring terminal, and the module provides per-point LED status indication that reflects the commanded state of the relay coil, not the contact continuity. Engineers should note this distinction: the LED confirms that the CPU has asserted the output, but does not confirm that the field-side load circuit is intact. For applications requiring contact-level diagnostics, a feedback input wired to an IC693MDL240 or equivalent discrete input module is the standard practice.

The IC693MDL940 is compatible with all Series 90-30 5-slot and 10-slot baseplate configurations, including the IC693CHS391, IC693CHS392, IC693CHS397, and IC693CHS398 racks. It is also supported in remote I/O expansion racks connected via the IC693BEM331 Bus Expansion Module. The module draws its logic power from the backplane’s 5 VDC rail (≤150 mA) and its relay coil power from the backplane’s 24 VDC rail (≤480 mA at full load, all 16 relays energized simultaneously). Panel designers must account for this coil current budget when sizing the rack power supply, particularly in high-density configurations where multiple relay output modules share a single IC693PWR321 or IC693PWR330 supply.

Relay contact life is rated at 100,000 electrical operations at rated resistive load (2 A, 240 VAC). For inductive loads—motor starters, solenoids—the effective contact life is reduced by the inrush and arc energy at contact break. Specifying a snubber network (RC or MOV) across the load terminals is standard practice to extend contact life and suppress radiated EMI at the switching instant. The module’s terminal block accepts 14–22 AWG field wiring, and the removable terminal block design allows pre-wired field connections to be transferred to a replacement module without rewiring.

Programming is handled through GE Proficy Machine Edition (v9.x and later) or the legacy Logicmaster 90-30 environment. The module is addressed as a standard discrete output block in the hardware configuration tree; no special function blocks or firmware downloads are required. The %Q reference address range assigned to the module is determined by its physical slot position in the rack, following the Series 90-30 automatic I/O addressing convention.

Real-time Stock & RFQ: [email protected] | WhatsApp: +86 18359268345

Technical Parameters

Hardware Logical Analysis

The IC693MDL940’s internal architecture is structured around three discrete functional layers that operate independently to ensure signal integrity and field-side fault containment.

Optical Isolation Stage: The backplane data bus drives a bank of 16 optocouplers, one per output channel. The optocoupler’s LED side is powered from the 5 VDC logic rail; the phototransistor side drives the relay coil circuit from the 24 VDC backplane rail. This arrangement means that a complete failure of the 24 VDC coil supply—whether from a blown fuse or supply fault—will de-energize all relay coils and open all contacts, placing the field loads in a known de-energized state. The logic bus remains unaffected, and the CPU can continue executing the control program and logging the fault condition.

Relay Contact Stage: Each relay is a sealed, bifurcated-contact design. Bifurcated contacts provide two parallel current paths per contact, which reduces the probability of a high-resistance contact failure caused by surface oxidation or contamination—a relevant consideration in environments with airborne particulates or humidity cycling. The relay coil incorporates a flyback diode across the coil terminals to suppress the inductive voltage spike at de-energization, protecting the optocoupler’s phototransistor from reverse-voltage stress.

EMC Design: The module’s PCB layout routes the 24 VDC coil drive traces with a ground plane return directly beneath them, minimizing the loop area of the coil current path and reducing radiated magnetic field emissions at the relay switching frequency. The field-side terminal block is physically separated from the logic PCB by a creepage and clearance distance compliant with IEC 60664-1 for 300 V rated insulation, which satisfies the requirements for 240 VAC field wiring without additional insulation barriers.

Thermal Management: At full load (16 relays energized, 2 A per contact), the module’s internal power dissipation is dominated by relay coil resistance losses (~30 mW per coil) and contact resistance losses (~20 mW per contact at 2 A). Total worst-case dissipation is approximately 800 mW, which is within the passive convection cooling capacity of the standard Series 90-30 rack without forced air. The module does not require a fan or heat sink under any rated operating condition.

System Integration Benefits

• Deterministic I/O scan latency: Output state changes are transferred from the CPU’s %Q table to the module’s output latch on every I/O scan cycle, with no buffering or queuing delay introduced by the module itself. Scan-to-contact latency is bounded and predictable, which is a prerequisite for time-critical interlock logic.
• Mixed-voltage field wiring from a single module: The dry-contact relay architecture allows different output points on the same module to switch different field voltages—some points at 120 VAC, others at 24 VDC—without any hardware reconfiguration. This reduces the number of modules required in mixed-voltage panels.
• Removable terminal block for zero-rewiring replacement: The field wiring terminates on a removable connector that separates from the module body. A failed module can be replaced in under two minutes without disturbing field wiring, reducing mean time to repair (MTTR) in production environments.
• Per-point LED diagnostics for rapid fault localization: Each output’s LED state is visible from the front of the rack without opening the panel door. Maintenance technicians can identify a de-energized output in seconds, reducing diagnostic time compared to modules with aggregate status indicators only.
• No firmware or configuration download required: The module is recognized automatically by the Series 90-30 CPU based on its hardware ID. There is no module-level firmware to manage, version-control, or update, which eliminates a class of compatibility issues that affect intelligent I/O modules.
• Backplane fault isolation: The two-stage isolation (optical + relay contact) prevents field-side wiring faults—short circuits, ground faults, voltage transients—from propagating to the CPU backplane bus. This isolation boundary is a key factor in achieving IEC 61508 SIL 1 system-level safety integrity in relay output applications.
• Compatible with Series 90-30 redundancy architectures: In hot-standby CPU configurations using the IC693CPU374 and IC693RCM311, the IC693MDL940 participates in the synchronized output transfer without module-level changes. The standby CPU assumes control of the output table, and the relay states are maintained through the switchover.
• Long-term parts availability: The IC693MDL940 has been in continuous production and distribution for over two decades. New surplus and factory-new stock remains available through authorized distributors and specialist suppliers, supporting the long service life typical of Series 90-30 installations in utilities, water treatment, and heavy industry.

Quality Assurance & Global Logistics

Every IC693MDL940 unit dispatched from our Xiamen, China facility is sourced through verified industrial distribution channels with full traceability to the original GE Fanuc manufacturing lot. Pre-shipment inspection covers visual integrity of the module housing, label authenticity verification against GE’s published part marking standards, and a power-on functional check of relay coil energization for each output point where test fixtures permit.

Units are packed in anti-static bags with humidity indicator cards, placed in foam-lined cartons rated for international air freight handling. Export documentation—commercial invoice, packing list, and certificate of origin—is prepared to comply with customs requirements in the destination country. Xiamen’s port infrastructure supports direct air freight connections to major industrial hubs in Europe, Southeast Asia, the Middle East, and the Americas, with typical transit times of 3–7 business days for air express shipments. Sea freight consolidation is available for bulk orders where lead time permits. All shipments carry a 12-month warranty against manufacturing defects from the date of delivery.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
© 2026 siemensplc.com. All rights reserved.