ABB IC697BEM731 Retrofit-Ready Bus Controller for Series 90-70 Control Systems
The IC697BEM731 is a Remote I/O Bus Controller module designed for the GE Series 90-70 programmable logic controller platform — one of the most widely deployed rack-based control architectures in heavy industry, utilities, and process manufacturing. As original equipment manufacturers discontinue support for legacy Series 90-70 hardware, facilities running IC697BEM731 or its predecessor variants face increasing pressure to source verified replacement units, retrofit aging control cabinets, or migrate to modern distributed I/O architectures without disrupting production continuity.
SMARTNEXMSK supplies the IC697BEM731 as a tested, retrofit-ready replacement with a 12-month warranty, backed by pre-shipment functional verification and full documentation support. Whether you are replacing a failed bus controller mid-production, upgrading a legacy remote I/O drop, or planning a phased migration away from the Series 90-70 backplane, this module provides the compatibility and reliability your engineering team requires.
Upgrade Compatibility Table
| Parameter | IC697BEM731 Specification | Retrofit Notes |
|---|---|---|
| Module Type | Remote I/O Bus Controller | Direct replacement for IC697BEM711, IC697BEM721 in same rack slot |
| Backplane Interface | Series 90-70 VME-based backplane | Compatible with IC697CHS750, IC697CHS782, IC697CHS790 racks |
| Communication Protocol | GE Series 90-70 Remote I/O Bus (proprietary) | Verify bus termination resistor settings before installation |
| Power Requirement | +5 VDC via backplane (supplied by IC697PWR710 or IC697PWR724) | Confirm PSU capacity before adding additional I/O drops |
| Module Address | Configurable via rotary switch (0–7) | Match address to original module; update Logicmaster 90 or Proficy ME configuration |
| I/O Drop Capacity | Up to 8 remote I/O drops per bus controller | Audit existing drop count before replacement to avoid address conflicts |
| HMI Compatibility | Compatible with CIMPLICITY, iFIX, and legacy GE View screens | No HMI screen changes required for direct module swap |
| Programming Tool | Logicmaster 90-70 / Proficy Machine Edition | Backup existing program before replacement; verify I/O table mapping |
| Installation Format | Single-slot VME module | No mechanical modification required for same-generation rack |
| Warranty | 12-Month Warranty — all units tested prior to shipment | |
Retrofit Planning for Existing Automation Systems
Successful IC697BEM731 retrofits begin with a thorough audit of the existing control cabinet. In most Series 90-70 installations, the bus controller shares a rack with the CPU — typically an IC697CPU731 or IC697CPU772 — along with discrete and analog I/O modules such as the IC697MDL340 (24 VDC input) and IC697ALG320 (analog input). Before pulling the failed bus controller, engineers should document the rotary address switch position, record all terminal wiring on adjacent I/O modules, and photograph the backplane slot layout.
Power budget verification is critical. The IC697PWR710 or IC697PWR724 power supply modules must have sufficient headroom to support the IC697BEM731 alongside all co-resident modules. Adding a new remote I/O drop — for example, expanding with an IC697CHS750 expansion rack populated with additional IC697MDL753 relay output modules — will increase backplane current draw and must be calculated before commissioning.
For facilities migrating from older bus controller variants such as the IC697BEM711, the physical swap is straightforward, but the Proficy Machine Edition hardware configuration must be updated to reflect the new module revision. Communication link integrity between the bus controller and remote I/O drops should be verified using the built-in diagnostic LEDs before restoring the CPU to RUN mode. If the installation includes a IC697CMM742 communications coprocessor for Ethernet or serial connectivity, confirm that the bus controller address does not conflict with the coprocessor’s rack slot assignment.
Facilities running mixed-generation racks — combining Series 90-70 hardware with newer PACSystems RX7i components — should note that the IC697BEM731 is not compatible with the RX7i CPU module directly. In such hybrid environments, the bus controller must remain on a dedicated Series 90-70 CPU rack, with inter-system communication handled via the IC697CMM711 or an equivalent protocol bridge. Programming cables such as the IC690ACC901 serial programming cable remain compatible for field diagnostics and program backup during the retrofit process.
Downtime Control During System Migration
Minimizing unplanned downtime during a Series 90-70 bus controller replacement requires a structured pre-outage preparation protocol. Before the maintenance window opens, the engineering team should use Proficy Machine Edition or Logicmaster 90-70 to perform a full program backup — capturing the ladder logic, I/O configuration, and hardware configuration file — and store it on an isolated engineering workstation. This backup protects against configuration loss in the event that the replacement module requires a fresh hardware configuration download.
During the swap, the CPU should be placed in STOP mode before removing the IC697BEM731. All remote I/O drops on the affected bus will lose communication during this period; field devices connected to those drops will hold their last output state or de-energize depending on the configured fault action. Documenting the expected fault behavior for each output module — particularly for safety-critical outputs controlled by IC697MDL753 relay modules — is essential to prevent unintended machine motion during the changeover.
After installing the replacement IC697BEM731, verify the rotary address switch matches the original setting, reseat the module firmly into the VME backplane, and restore power. The CPU should be returned to RUN mode only after all remote I/O drops have re-established communication, confirmed by the BUS OK LED on the bus controller front panel. A controlled I/O force test on non-critical outputs is recommended before releasing the line to production. Total planned downtime for a direct IC697BEM731 swap in a well-prepared environment is typically 30–90 minutes.
Retrofit Support FAQ
Q: Is the IC697BEM731 a direct drop-in replacement for the IC697BEM711 and IC697BEM721?
A: Yes. The IC697BEM731 is backward compatible with earlier Series 90-70 bus controller variants in the same rack slot. The rotary address switch must be set to match the original module’s address, and the Proficy Machine Edition hardware configuration should be updated to reflect the correct module catalog number before downloading to the CPU.
Q: What pre-shipment testing does SMARTNEXMSK perform on the IC697BEM731?
A: Every IC697BEM731 unit is functionally tested on a live Series 90-70 rack prior to shipment, verifying backplane communication, remote I/O bus initialization, and LED status indication. A test report is available upon request. All units are covered by a 12-month warranty from the date of shipment.
Q: Do I need to modify my existing terminal wiring when replacing the IC697BEM731?
A: No terminal wiring changes are required for a direct module replacement. The IC697BEM731 does not have field wiring terminals — it communicates via the VME backplane and the remote I/O bus cable. Wiring on adjacent I/O modules such as the IC697MDL340 or IC697ALG320 remains undisturbed during the swap.
Q: Can the IC697BEM731 be used in a PACSystems RX7i rack?
A: No. The IC697BEM731 is designed exclusively for the Series 90-70 VME backplane architecture and is not compatible with the PACSystems RX7i rack or CPU. For RX7i migrations, a separate remote I/O adapter module is required. Contact SMARTNEXMSK for migration path guidance specific to your installed base.
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