Description
Reliance Electric 770.90.00CXQ | MERI PLC Autobus Interface Module
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Reliance Electric |
| Model | 770.90.00CXQ |
| Product family | AutoMax PLC |
| Card designation | MERI Card |
| Functional type | PLC Autobus Interface Module |
| Rack installation | AutoMax card rack |
| Rack occupancy | 1 slot |
| Port count | 8, identified as Port 0 through Port 7 |
| Front-panel status | Ready LED plus eight port LEDs |
| Field terminals | Four terminal strips, eight connections each |
| Approx. base-card weight | 2.30 lb / approximately 1.04 kg |
| Exact CXQ electrical ratings | Not sufficiently verified from public documentation |
The documented 770.90.00 family is identified as a PLC Autobus I/F Module, also known as a MERI card. It mounts directly in an AutoMax card rack and occupies one slot. The documented front panel provides eight port indicators labeled 0 through 7 and four terminal strips with eight connections each.
Product Introduction
The Reliance Electric 770.90.00CXQ belongs to the legacy AutoMax MERI card family used for PLC Autobus interfacing inside an AutoMax rack. Its role is fundamentally an interface function, rather than a standalone CPU, power supply, analog input module, or general-purpose Ethernet communication card. The documented 770.90.00 family is installed directly into an AutoMax rack backplane and uses one card position.
For maintenance teams supporting older Reliance control systems, this distinction matters. Replacing a MERI card with a superficially similar PLC communication module can leave the rack architecture incompatible even when the replacement physically fits. The eight-port arrangement and front-panel diagnostics are important identification points when checking a spare against an installed card.
770.90.00CXQ
Application Scenarios & Field Pitfalls — Engineer’s Perspective
Engineering Pain Point
A common maintenance problem with legacy AutoMax equipment is finding a replacement based only on a shortened part number. The documented base family is 770.90.00, while the supplied 770.90.00CXQ carries an additional suffix that should be preserved during procurement. Current component listings consistently identify the CXQ version as a MERI PLC module, but public technical documentation does not adequately decode every suffix character.
Typical Applications
- AutoMax PLC rack maintenance — replacement of failed MERI interface cards in existing control racks.
- Legacy industrial machine control — maintaining older Reliance Electric automation installations without redesigning the complete rack.
- PLC Autobus interfacing — supporting the documented Autobus interface function of the MERI card.
- Plant spare-parts inventory — holding a correctly identified card for an aging AutoMax installation where original hardware remains operational.
Technical Pitfalls to Avoid
- Do not treat 770.90.00CXQ as a generic PLC CPU. The documented 770.90.00 family is specifically an Autobus interface/MERI card.
- Do not assume the CXQ suffix is interchangeable with every 770.90.00 variant. The family contains other suffix configurations, so compare the complete nameplate and existing rack documentation before substitution.
- Do not infer voltage, current, or communication protocol from unrelated MERI listings. Public listings contain inconsistent descriptions; exact CXQ electrical data should be confirmed against the installed card, original Reliance documentation, or system drawings.
Related Products
- Reliance Electric 770.90.00 — Base MERI/PLC Autobus interface card family from which the CXQ configuration is derived.
- Reliance Electric 770.90.00CTQ — Another documented MERI-related configuration; do not assume electrical interchangeability with CXQ.
- Reliance Electric 770.90.00BYS — MERI card configuration using the 770.90.00 family designation.
- Reliance Electric 770.90.10 — Later Autobus interface MERI module identified in secondary documentation as a replacement for the 770.90.00 family.
- Reliance Electric 770.90.10DXX — Another later MERI/PLC interface configuration; exact substitution should be checked against the AutoMax rack and application.
- Reliance Electric 770.09.00CRR — Related MERI PLC module designation frequently appearing in legacy Reliance inventories.
- Reliance Electric 812.68.00ESX — Different Reliance PLC output hardware; not a functional substitute for the MERI interface card.
- Reliance Electric DCC53120 — Different Reliance control hardware family and should not be treated as a direct MERI replacement.
Procurement Note
For a 770.90.00CXQ replacement, specify the complete part number, not merely “770.90.00.” Verify the suffix, faceplate labeling, eight-port arrangement, terminal configuration, AutoMax rack position, and any installed application-specific configuration before installation.
The strongest available technical identification is Reliance Electric AutoMax MERI PLC Autobus Interface Module. Public sources confirm the base 770.90.00 architecture, but they do not provide enough reliable information to publish exact CXQ-specific voltage, current, or protocol specifications. That uncertainty is preferable to carrying an incorrect specification into a plant spare-parts database.
