The GE IC695RMX128 (Revision CA-DG) is a high-speed Memory Xchange (RMX) module specifically designed for the PACSystems RX3i platform. This module is the physical link that enables CPU Redundancy. In a redundant system, two RX3i CPUs (Primary and Secondary) are connected via RMX modules to ensure that the “Secondary” CPU has an exact, real-time mirror of the “Primary” CPU’s memory. This allows for a seamless “bumpless” transfer of control if the primary controller fails.
Product Specifications (Datasheet)
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Model: IC695RMX128CA-DG
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Module Type: Redundancy Memory Xchange (RMX)
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Fiber Optic Interface: 2 x SFP (Small Form-factor Pluggable) ports
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Fiber Type: Multi-mode (Standard) or Single-mode (depending on SFP choice)
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Memory Capacity: 128 MB of high-speed reflective memory
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Data Transfer Rate: 2.12 Gbaud
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Transfer Delay: Less than 1 microsecond per node
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Backplane: Universal Backplane (PCI Bus)
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Current Consumption: 750 mA @ 3.3 VDC
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Operating Temperature: 0°C to +60°C
Key Application Fields
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Critical Infrastructure: Water treatment plants and power distribution where downtime is not acceptable.
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Oil & Gas: Controlling emergency shutdown systems (ESD) and offshore platform processes.
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Continuous Processing: Chemical and pharmaceutical manufacturing where a system halt would result in significant product loss.
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Marine & Offshore: Redundant steering and propulsion control systems for large vessels.
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Large-Scale HVAC: Managing climate control in mission-critical data centers.
Product Usage Instructions
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Hardware Configuration: You must have two identical RX3i racks, each containing an identical CPU and at least one IC695RMX128 module.
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Fiber Link: Connect Port 1 of the RMX in Rack A to Port 1 of the RMX in Rack B using a high-quality fiber optic patch cable. For “Dual Redundancy,” a second RMX module and fiber link can be used to prevent a single point of failure in the redundancy link itself.
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SFP Modules: Ensure that the SFP modules inserted into the RMX ports match your fiber type (usually multi-mode for distances under 300 meters).
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Software Setup: Use PAC Machine Edition (PME) to configure the Redundancy Target. You must define the “Redundant IP” and specify which memory areas (%I, %Q, %G, %R, etc.) should be synchronized across the RMX link.
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Status Check: Monitor the LEDs on the module faceplate. The “LINK” LED must be solid green on both modules to indicate that the reflective memory is successfully synchronized.
Q&A: Frequently Asked Questions
Q: Does the RMX module handle the I/O communication? A: No. The RMX only synchronizes the CPU memory. The I/O is typically handled via a separate PROFINET or Genius network that is accessible to both CPUs simultaneously.
Q: Can I use the 128MB RMX with a 64MB RMX? A: No. For stable redundancy, both modules must have identical memory capacities and preferably the same firmware/revision level (e.g., CA-DG).
Q: How far apart can the two redundant racks be? A: With standard multi-mode fiber and SFPs, the racks can be up to 300 meters apart. With single-mode fiber and specialized SFPs, this distance can be extended up to 10 kilometers.
Q: What is “Reflective Memory”? A: It is a technology where any data written to the memory on Module A is automatically and near-instantaneously “reflected” or copied to Module B via the fiber optic link without requiring CPU processing time.
Ensure your process stays online with the IC695RMX128CA-DG and other essential GE PACSystems RX3i redundancy components.
Similar Model Recommendations
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GE IC695RMX128-BC: An earlier revision of the 128MB RMX module.
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GE IC695CRU320: A dedicated Redundancy CPU often used in conjunction with RMX modules.
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GE IC695PNC001: The PROFINET Controller used to manage redundant I/O networks.
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GE IC695PSA040: The high-capacity power supply required for redundancy-heavy racks.
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GE IC695RMX64: A 64MB version of the Memory Xchange module for systems with smaller synchronization requirements.
