Description
System Architecture & Operational Principle
The IC693MDR390C occupies a single slot on the GE 90-30 universal backplane, functioning as a discrete sourcing output interface at Level 1 of the Purdue Model (Basic Control). It receives output commands from the CPU via %Q memory mapping and switches 12-24V DC power to field devices. Upstream, the CPU writes output states during each PLC scan; downstream, the module provides current limiting, group fusing, and inductive flyback protection for field device control.
The -C suffix indicates this is a mid-production revision of the IC693MDR390 platform, representing incremental component updates and manufacturing optimizations from earlier revisions (A and B). This revision may include subtle internal component substitutions for obsolescence management or improved thermal performance, but retains the core architecture of the base design. The module’s sourcing (source) configuration means it sources current from the module output terminal to the field device load, with the load return connected to DC common (0V).
GE IC693MDR390
Core Technical Specifications
- Specific Revision: Mid-production revision (-C) with component updates vs. earlier -A and -B revisions
- Physical Interface: 40-pin terminal block (2 connectors, 16 points each) or front-facing removable terminal block option
- Internal Bus: 90-30 universal backplane (5V DC power, signal exchange via %Q memory)
- Output Type: 32-point discrete output, 12-24V DC, sourcing (source configuration)
- Output Voltage Range: 12-24V DC (nominal 24V DC)
- Output Current: 0.5A per point maximum, 2A per 4-point group maximum
- Isolation: 1500V RMS optical isolation between field side and backplane; outputs share common DC return
- Backplane Current Draw: Approximately 650mA @ 5V DC
- Response Time: 1ms typical turn-on, 1ms typical turn-off (inductive loads may have longer decay)
- LED Indicators: Individual LEDs per output point (ON when output energized) plus module status LEDs
- Environmental: Manufacturing optimizations may improve thermal management vs. earlier revisions
- Letter Code: Revision letter C indicates a mid-production iteration with incremental improvements
- Terminal Block: 40-pin plug-in terminal block, supports wire gauges 22-14 AWG
- Field Wiring: Sourcing configuration—module outputs source +24V to field device, load return to DC common (0V)
- Protection: Individual point current limiting, group fusing (4 outputs per 2A fuse), built-in flyback diodes for inductive loads
- Diagnostic Capabilities: No onboard diagnostics beyond LED indication (discrete module, not intelligent)
- Short-Circuit Protection: Individual point current limiting plus group fuse protection
Customer Value & Operational Benefits
Improved Thermal Management from Mid-Production Updates
The IC693MDR390C incorporates component updates and manufacturing optimizations from earlier revisions, potentially including improved thermal management characteristics. Mid-production revisions often address thermal stress points identified in earlier iterations, resulting in a module with better heat dissipation and reduced susceptibility to thermal-related failures. Facilities installing -C modules benefit from these incremental improvements that enhance reliability, particularly in demanding environments with high ambient temperatures or continuous high-current operation.
Group Fusing Protection Prevents Catastrophic Failure
The IC693MDR390C’s 4-point group fusing (2A per group) provides targeted overcurrent protection that prevents a single short-circuit from disabling all 32 outputs. If one output shorts to ground, only its 4-point group is affected—other groups continue operating normally. This design improves fault tolerance compared to modules with a single common fuse for all outputs, where one short would disable the entire module. For critical applications where output availability is paramount (e.g., safety interlocks, emergency shutdown systems), this group-level protection minimizes the impact of field wiring faults.
Built-In Flyback Protection for Inductive Loads
The module includes built-in flyback diodes for inductive load protection, eliminating the need for external clamp diodes across relay coils, solenoid valves, or motor starter coils. When an inductive load de-energizes, the collapsing magnetic field generates a high-voltage spike that can damage output transistors. The built-in diodes clamp these spikes to safe levels, protecting the module and reducing external component count. This simplifies wiring and reduces the risk of field technicians omitting external protection components—a common cause of output module failure in retrofits.
GE IC693MDR390
Field Engineer’s Notes (From the Trenches)
Here’s a nuance for the -C revision: while functionally identical to earlier 390 revisions, the mid-production updates may include subtle changes to the fuse holder design or terminal block plastics that affect field servicing. I’ve encountered -C modules with updated fuse carriers that require slightly different fuse puller tools compared to earlier -A and -B revisions. The lesson? Verify the fuse holder design on your specific -C module before stocking replacement fuses or tools. Also, the -C revision may include improved thermal pad materials between the output transistors and the module heatsink—visible as darker or thicker thermal material when the module is disassembled. However, you won’t see this externally, and it doesn’t change the current ratings. Don’t assume the -C can handle more current just because it’s “newer”—the 2A per-group limit remains unchanged. Finally, the -C revision’s backplane current draw is approximately 650mA at 5V DC—identical to earlier revisions. I’ve seen techs assume mid-production updates reduced power consumption, then overload racks by adding too many -C modules. The current draw hasn’t changed, so your backplane power budget calculations remain the same.
Real-World Applications
Automotive Assembly Line Solenoid Valve Control
In automotive final assembly plants, the IC693MDR390C controls 32 solenoid valves on pneumatic actuators for divert gates, clamp cylinders, and lift mechanisms. The -C revision’s potentially improved thermal management is valuable for these high-cycle applications where outputs may switch hundreds of times per hour, generating significant heat. The module’s 0.5A per-point capacity handles most standard pneumatic valves, while the 2A per-group fusing protects against short-circuits in valve wiring harnesses. The built-in flyback diodes eliminate the need for external clamp diodes across each valve coil, simplifying wiring in the crowded control cabinet. The per-point LED indicators enable rapid troubleshooting—technicians can visually identify which valve output is energized or which group fuse has blown without connecting to the PLC.
Packaging Machine Indicator Light and Relay Control
In high-speed packaging machinery, the IC693MDR390C controls 32 indicator lights (tower lights, status LEDs) and control relays for conveyor motors, packaging actuators, and sealing mechanisms. The -C revision’s component updates may provide enhanced reliability for these high-speed packaging operations where module replacement downtime is costly. The group fusing protection ensures that a shorted indicator light or failed relay coil doesn’t disable all outputs on the module—only its 4-point group is affected. The built-in flyback diodes protect the module from inductive kickback when relay coils de-energize, eliminating the need for external protection components.
High-Frequency Troubleshooting FAQ
What is the difference between IC693MDR390C and earlier 390 revisions?
The is a mid-production revision of the 390 platform, incorporating component updates and manufacturing optimizations compared to earlier revisions (A and B). Functionally, the modules are identical—32 output points, 12-24V DC, sourcing outputs, identical current ratings, fusing, and response time. The -C revision may include subtle internal component substitutions for obsolescence management or improved thermal performance, but these changes do not affect field operation. No programming changes, wiring modifications, or configuration updates are required when upgrading from earlier revisions—the -C is a drop-in replacement with functional parity.
Yes, later revisions of the IC693MDR390 (such as -E, -F, or -G) are fully compatible and will operate interchangeably in a GE 90-30 system. Later revisions typically incorporate additional component updates or manufacturing improvements, but maintain functional parity with the -C revision. No programming changes or wiring modifications are required when upgrading—the module is recognized identically in the PLC configuration. In fact, upgrading to a later revision may provide enhanced thermal management or reliability features, particularly for high-current or high-temperature applications.
Do I need to change fuse ratings when upgrading to the -C revision?
No, the fuse ratings remain unchanged from earlier revisions. Each 4-point group on the continues to be factory-fused at 2A maximum. The -C revision does not alter current ratings or fuse specifications. Use the same 2A replacement fuses that you used for earlier -A and -B revisions. However, verify the fuse holder design on your specific -C module—mid-production updates may include updated fuse carrier designs that require different fuse puller tools or have slightly different form factors. Always have the correct replacement fuses and tools on hand before servicing the module.
How do I handle the backplane current draw when adding -C modules?
The ‘s backplane current draw is approximately 650mA at 5V DC—identical to earlier revisions. When adding -C modules to a rack, use the same backplane power budget calculations that you used for earlier revisions. Calculate total 5V current draw from all modules in the rack, including the CPU, analog modules, and other discrete modules. Ensure your power supply has adequate headroom (recommend operating at 80% or less of rated capacity). The -C revision does not reduce power consumption, so don’t assume you can add more modules just because it’s a “newer” revision.
Commercial Availability & Pricing
Please note: The listed price is not the actual final price. It is for reference only and is subject to appropriate negotiation based on current market conditions, quantity, and availability.
