Description
- Model: GE IC695CRU320
- Brand: GE Fanuc (now Emerson/GE Automation)
- Series: PACSystems RX3i
- Core Function: High-availability redundant CPU for critical control applications
- Product Type: Central Processing Unit (CPU) – Redundancy Enabled
- Key Specs: 1 GHz Celeron M Processor 64 MB User Memory PCI Backplane support
- Processor Speed: 1 GHz
- User Memory: 64 Megabytes (Non-volatile battery-backed)
- Redundancy Support: Hardware-based synchronization for Hot Standby
- Backplane Support: Dual Bus (PCI and Serial)
- Communication Ports:
- 1 x RS-232 (Serial)
- 1 x RS-485 (Serial)
- Supports Ethernet via IC695ETM001
- Programming Language: Ladder Diagram (LD), Structured Text (ST), Function Block (FBD), C
- Execution Speed: 0.022 ms per 1K of Boolean logic
- Power Consumption: 1.25 Amps @ +5 V DC; 1.0 Amps @ +3.3 V DC
- Operating Temperature: 0 to +60 °C (32 to 140 °F)
GE IC695CRU320
Application Scenarios & Pain Points
The IC695CRU320 is the heavy hitter of the RX3i line, specifically designed for “Zero-Down-Time” environments. Unlike the standard CPU320, the CRU320 includes the logic and synchronization ports required to link two identical CPUs together in a “Hot Standby” configuration. The biggest pain point with redundant systems is “Sync Loss.” If the synchronization fiber optic link or the hardware timing on one board begins to drift, the secondary CPU will fail to track the primary, leaving the plant vulnerable to a total shutdown if the primary fails.
Typical Application Scenarios:
- Continuous Process Chemical Plants: Where a 5-second CPU failure could result in a dangerous pressure spike or solidified product in pipes.
- Data Center Cooling: Managing redundant HVAC systems where thermal runaway must be avoided at all costs.
- Infrastructure (Tunnels/Bridges): Controlling ventilation and emergency lighting systems that require 99.999% uptime.
- Oil & Gas Pipelines: Managing compression stations across long distances where manual intervention is impossible.
Case Study: The Seamless Failover
Background: A municipal power plant used a pair of IC695CRU320 CPUs to manage the cooling water intake for their turbines.
The Problem: During a routine maintenance check, the primary CPU cabinet was accidentally struck by a forklift, severing the local power feed. Normally, this would have tripped the turbine.
The Solution: Because they were using the CRU320 redundancy architecture, the secondary CPU—which had been tracking the primary’s memory state in real-time—took over the I/O control in less than one logic scan (approx. 20ms).
The Result: The operators in the control room saw a “Primary CPU Loss” alarm, but the cooling water pumps never skipped a beat. They were able to restore power to the primary cabinet while the plant continued at full capacity. The CRU320 paid for itself in that single 20ms window.
GE IC695CRU320
Compatible Replacement Models
| Original Model | Replacement Model | Compatibility | Main Difference | Effort Level |
| IC695CRU320 | IC695CPE330 | ⚠️ Software Compatible | Newer, built-in Ethernet, faster | Medium (Update firmware) |
| IC695CRU320 | IC695CPU320 | ❌ Incompatible | Non-redundant version | High (Lacks sync logic) |
| IC695CRU320 | IC695CRU320 (Any Rev) | ✅ Direct Replace | Later revisions have updated memory | Zero (Plug and Play) |
SOP & Quality Transparency
Testing a redundancy CPU is twice as complex as a standard CPU because we must verify its “relationship” with its partner.
- Synchronization Port Stress Test: We connect the CPU to a redundancy link and verify that it can successfully “transfer” a 64MB data block to a partner unit without parity errors.
- Backplane Burst Test: We verify the PCI bus communication speed to ensure it can handle high-density I/O racks.
- Battery-Backed RAM Audit: We power the unit down for 48 hours and verify that the user program and register states are perfectly preserved.
- Real-Time Clock (RTC) Accuracy: We verify that the internal clock does not drift more than 1 second per day, which is critical for time-stamped alarm logging in redundant pairs.
- Firmware Consistency: We ensure the CPU is flashed with a stable, production-ready firmware version. Upon request, we can match your specific site firmware version.
GE IC695CRU320
Troubleshooting Quick Reference
| Symptom | Possible Cause | Relation to CRU320 | Quick Check |
| “OK” LED Off | Hardware Watchdog Trip | ✅ High | Check for internal power supply failure or 3.3V rail fault. |
| “RUN” LED Flashing | CPU is in “Stop” Mode | ⚠️ Medium | Check for a configuration mismatch or a “Fault Table” entry. |
| “BACKUP” LED Off | Redundancy Link Loss | ✅ High | Inspect the fiber optic synchronization cable or RMX module. |
| “FAULT” LED Red | I/O or Software Error | ⚠️ Medium | Connect with Proficy Machine Edition and clear the CPU fault table. |
Integrator’s Pro Tip: ❗ Match your Revisions. When running a redundant pair of IC695CRU320s, it is critically important that both CPUs have the exact same hardware revision and firmware version. I have seen systems “partially” sync, only to crash during a failover because the firmware handles memory mapping slightly differently between versions.
Additional Inventory Models
Maintaining an RX3i or Series 90-30 system? We have these parts ready:
- GE IC695ETM001 Ethernet Interface
- GE IC695RMX128 Redundancy Memory Xchange
- GE IC695PSA040 24V DC Power Supply
- GE IC695CHS007 7-Slot PCI Backplane
- GE IC694MDL660 24V DC Discrete Input
- GE IC695CRU320 (This Model)
- GE IC695PNC001 Profinet Controller
- GE IC695ALG600 Analog Input Module
For technical support or to request a 24-hour express shipment, visit www.newplcdcs.com.
