GE PACSystems RX3i IC695CRU320-EN – Redundant Controller Unit for High‑Availability RX3i Systems

The IC695CRU320-EN is a redundancy-class controller unit for the PACSystems RX3i platform. It’s designed to run a hot-standby pair of RX3i racks, keeping your process running even if the primary side drops out. From my experience, this is the module plants turn to when they need predictable switchover behavior without re-architecting their I/O. Typical applications include water and wastewater treatment, power generation auxiliaries, chemical batching, and any manufacturing cell where downtime is expensive.

You might notice that “CRU” units in the RX3i family focus on coordinating redundancy: synchronizing logic, memory, and I/O status between the Primary and Backup racks. In many cases, it works alongside Ethernet or PROFINET network modules and a reflective memory link to make switchover smooth and fast.

Company’s Order Placement Process and Guarantees

• Warranty: 365 days
• Delivery: 1 week if in stock; no more than one month at the latest
• Payment: 50% advance payment; full payment prior to delivery
• Express options: FedEx, UPS, DHL

Key Features

• Hot-standby redundancy – Coordinates a Primary/Backup RX3i pair to minimize process disruption; switchover time typically depends on your I/O network and redundancy link.
• RX3i backplane integration – Installs in IC695 series racks and works with the extensive RX3i I/O family (discrete, analog, motion, and specialty modules).
• Network flexibility – Commonly used with IC695ETM001 (Ethernet) or IC695PNC001 (PROFINET) for redundant networks; many deployments use IC695RMX128 as the redundancy link.
• Deterministic state synchronization – Keeps logic, key data blocks, and process state aligned so the Backup can assume control quickly.
• Firmware upgradable – Field-updatable through Proficy Machine Edition (PME), which helps standardize versions across both racks.
• Front-panel diagnostics – Clear status indicators for RUN/STOP, OK/FAULT, and redundancy state make on-site checks faster.
• Industrial temperature rating – Suitable for typical control cabinets in plant environments.

A maintenance engineer at a municipal WTP told us their RX3i pair with CRU units “just keeps tracking” during firmware maintenance windows; they typically plan switchover overnight and the backup assumes control without retuning the loops.

Technical Specifications

Related or Supporting Products

• IC695RMX128 – Reflective memory module often used as the redundancy link between the Primary and Backup racks.
• IC695ETM001 – Ethernet interface for RX3i; add to each rack for redundant Ethernet topologies.
• IC695PNC001 – PROFINET Controller module; supports distributed I/O with media-redundant networks.
• IC695PSA040 / IC695PSD040 – RX3i power supplies; pick footprint/output to match rack and load.
• IC695CHS012 / IC695CHS016 – 12-slot / 16-slot RX3i racks used in redundant configurations.
• IC695CPU320 – Non-redundant RX3i CPU in the same performance class; good when a single controller is sufficient.
• IC695CPE330 – RX3i CPU with embedded Ethernet; a frequent upgrade path when you want integrated networking but don’t need CRU redundancy.

One thing I appreciate is that the CRU-based pair lets you reuse existing RX3i I/O and wiring; you’re not forced into a whole new platform to get high availability.

Installation & Maintenance

• Cabinet & rack – Use matching IC695CHS racks on both sides; panel-mount with proper bonding/grounding. Provide ventilation per the RX3i manual; avoid hot spots near power devices.
• Wiring & networks – Keep Ethernet/PROFINET cabling redundant and segregated where practical. If using reflective memory (IC695RMX128), follow the specified media type and maximum segment lengths.
• Version alignment – Keep firmware matched across both racks (CRU/CPU, comms, I/O where applicable). Proficy Machine Edition simplifies bulk updates.
• Redundancy checks – Verify Primary/Backup roles, hot-standby status, and switchover test procedures during FAT/SAT and after any configuration change.
• Routine maintenance – Inspect connectors and module latches quarterly; review diagnostics logs; back up the project and retentive data; replace the clock/retentive memory battery on interval (typically annually, depending on usage and site policy).
• Safety – De-energize the rack before inserting/removing modules unless the manual explicitly allows online replacement for that slot; observe ESD protection while handling modules.

Quality & Certifications

• Manufactured to industry standards; CE and UL/cUL markings are typical for RX3i modules.
• RoHS compliant build in most revisions.
• Manufacturer’s standard product warranty applies; we provide a 365‑day warranty on supply.