Description
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | GE Intelligent Platforms / GE Fanuc |
| Product Family | PACSystems RX3i |
| Model | IC695CPU315-BB |
| CPU Type | RX3i Central Processing Unit |
| Processor | 1 GHz Intel Celeron M |
| Operating System | VxWorks |
| User Memory | Up to 20 MB battery-backed RAM |
| Flash Memory | 20 MB non-volatile user flash |
| Program Blocks | Up to 512 |
| Maximum Block Size | 128 KB |
| Discrete Reference Memory | 32 Kbits %I / 32 Kbits %Q |
| Analog Reference Memory | Up to 32 Kwords %AI / %AQ |
| Symbolic Memory | Configurable up to 20 MB |
| Serial Interfaces | 1 × RS-232, 1 × RS-485 |
| Serial Protocols | SNP, Modbus RTU Slave, Serial I/O |
| Backplane | RX3i PCI + high-speed serial backplane |
| Floating Point | Yes |
| Typical Boolean Speed | 0.047 ms / 1,000 Boolean instructions |
| Power Requirement | +3.3 VDC: 1.0 A; +5 VDC: 1.2 A nominal |
| Operating Temperature | 0 to 60°C |
| Battery | IC695ACC302 recommended; IC693ACC302 also supported |
| Rack Occupancy | 2 RX3i slots |
| Firmware Revision for -BB | 6.70 at introduction |
The CPU315 specification identifies dual RX3i backplane support, with a PCI bus for newer high-speed modules and a serial backplane for legacy Series 90-30 I/O migration.
One useful procurement detail: IC698ACC701 is not compatible with CPU315. The documented battery choices are IC695ACC302 or the Series 90-30 IC693ACC302 battery pack.
Application Scenarios & Pain Points
A CPU failure in an RX3i rack can stop an entire production cell even when every I/O module remains perfectly healthy. The replacement challenge is usually not mounting the CPU; it is preserving the application’s memory, firmware compatibility, and communication behavior.
- Process control: CPU315 was designed for real-time control of process equipment, including applications in water/wastewater and power/process control.
- Machine automation: The 1 GHz processor and large memory allocation suit control programs with substantial logic and data requirements.
- Legacy Series 90-30 migration: The dual backplane architecture allows the RX3i platform to communicate with existing serial-backplane I/O while using newer PCI-based RX3i modules.
- Serial equipment integration: Built-in RS-232 and RS-485 interfaces support SNP, Modbus RTU Slave, and Serial I/O applications without necessarily adding a separate serial interface module.
Field note: The CPU may appear to be the obvious culprit after a sudden RUN-state failure, but battery condition, power quality, backplane seating, and firmware/application issues should be checked before declaring the processor defective.
Brief Field Case
On an older RX3i machine, replacing the CPU without preserving the existing application can turn a ten-minute hardware swap into a lengthy restart effort. Before removing the original processor, capture the current hardware configuration, firmware revision, application backup, battery condition, and serial-port assignments.
IC695CPU315-BB
Related Products
- GE IC695CPU315-BB — Subject CPU315 hardware revision. Provides the RX3i processing engine, memory, and two onboard serial ports.
- GE IC695CPU315-AB — Earlier CPU315 revision. It introduced support for additional modules and Modbus RTU improvements; verify firmware and hardware compatibility before using it as a substitute.
- GE IC695CPU315-BC — CPU315 revision associated with firmware 6.71 and corrections related to logic-driven flash read/write services. Useful as a same-family comparison, but revision compatibility still needs checking.
- GE IC695CPU315-BD — Later revision adding support for the IC695PNC001 PROFINET Controller. This can be relevant when the RX3i system has PROFINET requirements.
- GE IC695CPU315-CE — Later revision associated with firmware 7.13 and additional diagnostic/service features. It is from the same CPU family but should not be treated as an uncontrolled drop-in replacement.
- GE IC695CPU320 — Higher-memory RX3i CPU family member with 64 MB user memory. It is a higher-capacity CPU option, not a casual replacement for .
- GE IC695ACC302 — Lithium Smart Battery recommended for memory retention. Battery condition is critical when battery-backed application data must be preserved.
- GE IC695ETM001 — RX3i Ethernet interface module used with -based systems for Ethernet communications. does not have the same embedded Ethernet architecture as later CPE CPUs.
- GE IC695PNC001 — RX3i PROFINET Controller module. Relevant to systems requiring PROFINET controller functionality, with support dependent on the CPU revision/firmware.
The Engineer’s Guide: Field Pitfalls to Avoid
WARNING 1 — Do not treat every revision as identical.
The suffix identifies hardware history. For example, introduced a hardware change for improved power-up noise immunity, while later revisions added or corrected other functions.
How to avoid it: Record the complete catalog number, hardware revision, firmware version, and application software version before purchasing a replacement.
WARNING 2 — Protect the application memory and check the battery.
uses 20 MB of battery-backed RAM in addition to 20 MB of flash memory. Loss of the battery-backed data can become a serious commissioning issue.
How to avoid it: Back up the application before removal whenever possible. Verify the installed battery type and condition. Do not use IC698ACC701 with ; it is specifically documented as incompatible.
WARNING 3 — Do not assume Ethernet is built into this CPU.
The provides RS-232 and RS-485 serial interfaces. Ethernet communication in the original architecture is provided through a rack-based Ethernet interface module such as IC695ETM001.
How to avoid it: Check the rack BOM before ordering. If the existing system depends on Ethernet, make sure the Ethernet interface module is present and supported by the CPU/firmware combination.
Frequently Asked Questions (FAQ)
What is GE IC695CPU315-BB?
IC695CPU315-BB is a central processing unit for the PACSystems RX3i PLC platform. It uses a 1 GHz Intel Celeron M processor and provides 20 MB of battery-backed RAM plus 20 MB of non-volatile flash user memory.
It is the control processor—not an I/O module or standalone Ethernet interface.
How much memory does the IC695CPU315-BB have?
The provides:
- 20 MB battery-backed user RAM
- 20 MB non-volatile flash user memory
The reference table also provides up to 32 Kbits each for discrete %I and %Q references and up to 32 Kwords each for %AI and %AQ, with symbolic memory configurable within the available user memory.
What communication ports are built into -BB?
The CPU has two onboard serial interfaces:
- RS-232
- RS-485
Supported serial protocols include SNP, Modbus RTU Slave, and Serial I/O.
If the existing application communicates with an Ethernet HMI, SCADA system, or other Ethernet device, check for the separate RX3i Ethernet interface hardware.
Is IC695CPU315-BB compatible with Series 90-30 I/O?
The RX3i architecture provides a dual backplane bus, combining the high-speed PCI backplane with a serial backplane that supports migration of existing Series 90-30 I/O.
That does not mean every Series 90-30 module is automatically supported. Verify the individual I/O module against the applicable RX3i compatibility documentation and firmware revision.
Can I replace with another revision?
Often this can be practical, but do not treat it as a blind swap. revisions have different firmware histories and feature changes. For example, the -BD revision added support for the IC695PNC001 PROFINET Controller, while other revisions addressed specific hardware or firmware issues.
Before substitution, compare:
- Complete catalog number.
- Hardware revision.
- Firmware version.
- Proficy Machine Edition project version.
- Installed I/O modules.
- Ethernet/PROFINET requirements.
- Serial-device configuration.
- Retained application data.
Does support PROFINET?
The original architecture can work with the IC695PNC001 PROFINET Controller, but support depends on the CPU hardware/firmware revision. The documented release history specifically identifies as adding support for the PNC001.
If the existing system relies on PROFINET, verify the exact CPU revision and firmware rather than assuming every suffix has identical capability.
What should I request when buying a replacement ?
For a production spare, request:
- Exact nameplate photograph.
- Hardware revision confirmation.
- Firmware version.
- CPU diagnostic/status test.
- Serial-port test.
- Backplane communication test.
- Memory/flash verification.
- Battery condition.
- Connector and backplane-contact inspection.
- Actual unit photographs.
- Written test report.
- Warranty.
The -BB suffix is worth preserving when the plant’s existing CPU is specifically documented as -BB. A cheaper with a different suffix may function, but the engineering question is whether its revision and firmware behavior match the installed control application.
