Executes the RX3i control application while participating in a synchronized primary and backup pair.
Key Information
IC695CRU320-EH is a PACSystems RX3i redundancy CPU for hot-standby controller pairs. The EH release appears in the manufacturer revision history with firmware 7.13 and 7.14 service updates.
A complete replacement must preserve the paired CPU hardware, project equality, redundancy transfer list, RMX synchronization links, firmware and failover logic. Treating IC695CRU320-EH as a stand-alone CPU omits the system relationships that make redundancy work.
Functions
Transfers symbolic and reference data through as many as two IC695RMX128 or IC695RMX228 links.
Supports maximum switchover within one logic scan, with a documented minimum of 3.133 ms.
Provides embedded RS-232 and RS-485 interfaces for supported serial protocols.
Specifications
| Manufacturer | Emerson PACSystems |
|---|---|
| Exact Model | IC695CRU320-EH |
| Product Type | RX3i redundancy CPU |
| Release Identity | EH hardware / firmware release family |
| User Program Memory | Up to 64 MB battery-backed RAM |
| Nonvolatile User Memory | 64 MB flash |
| Discrete Memory | 32 Kbits each for %I and %Q |
| Analog Memory | Up to 32 Kwords each for %AI and %AQ |
| Program Blocks | Up to 512; 128 KB maximum per block |
| Redundancy Transfer Data | Up to 2 MB |
| Synchronization Links | Up to two IC695RMX128 or IC695RMX228 links |
| Switchover | Maximum one logic scan; minimum 3.133 ms |
| Embedded Serial | RS-232 and RS-485 |
| Serial Protocols | Modbus RTU Slave, SNP and Serial I/O |
| Backplane Power | 1.0 A nominal at 3.3 VDC; 1.2 A nominal at 5 VDC |
| Operating Temperature | 0 to 60 °C |
| Clock Accuracy | Time-of-day drift up to 2 seconds per day |
| Memory Protection | Single-bit correction and multiple-bit checking |
Installation
- Obtain backups from both controllers and prove logic and configuration equality before shutdown.
- Record active/backup state, RMX link assignment, redundancy IDs, transfer-list size and all network addresses.
- Match IC695CRU320-EH revision and approved firmware between the paired racks; resolve differences before synchronization.
- Inspect batteries or energy-retention hardware, backplane capacity and RMX fiber paths.
- Commission synchronization, role transition, output ownership, fault annunciation and recovery during an approved failover test.
Lifecycle
- Retain paired serial numbers, IC695CRU320-EH firmware and RMX module revisions in one redundancy record.
- Periodically exercise failover under a controlled procedure instead of relying only on synchronized indicators.
- Archive the PAC Machine Edition project after every logic, hardware or transfer-list change.
- Review migration to CPE330 redundancy mode only against the documented Emerson compatibility path.
About IndustryParts
https://www.industryparts.com/Redundancy evidence travels with the CPU
IndustryParts handles IC695CRU320-EH with the paired controller record, RMX links and synchronization settings kept together.
- EH revision retained
- Transfer list saved
- Failover plan reviewed
FAQ
Why can two healthy IC695CRU320-EH CPUs refuse to synchronize?
Project inequality, firmware mismatch, RMX link assignment, redundancy-ID errors or transfer-list differences can block synchronization without indicating a failed CPU.
What should be supplied with an IC695CRU320-EH replacement request?
Provide both CPU labels, firmware, rack and power-supply revisions, RMX modules, active/backup status and the current project backup.
How should IC695CRU320-EH failover be verified?
Use a controlled test that confirms state transfer, output ownership, communications, alarms, switchover time and clean reintegration of the repaired unit.
Can a CPE330 replace IC695CRU320-EH without engineering changes?
A documented compatibility mode exists, but serial functions, firmware, PME support and redundancy configuration must be reviewed before migration.
What indicates a marginal synchronization path for IC695CRU320-EH?
Intermittent sync loss, transfer-list errors, unexpected role changes or recovery delays justify checking both RMX modules, fiber paths and configuration.
