Westinghouse 3A99168G02 Q‑Line QRO8 Relay Output Module

Product Profile
The Westinghouse 3A99168G02 is an 8‑channel QRO8 relay output card for the legacy Westinghouse Ovation Q‑Line DCS system. It is responsible for switching discrete field loads, executing on‑off control commands for plant auxiliary equipment. This Eurocard‑style board communicates through the Q‑Line backplane bus with Ovation controllers, converting internal logic commands into physical relay contact actions. Since OEM manufacturing has long been discontinued, refurbished and surplus units serve as critical spares for thermal power‑plant DCS cabinets to avoid large‑scale system retrofits.

Functional Deep‑Dive

Equipped with eight independent Form‑A SPST‑NO electromechanical relay channels, the 3A99168G02 provides full galvanic isolation between DCS control logic and external field circuits. Each relay contact supports switching of AC and DC loads for solenoid valves, motor auxiliary circuits, local panel indicators and external interlock relays. On‑board circuitry receives command data over the Q‑Line backplane, drives relay coils, and feeds back channel status and fault diagnostics to the Ovation controller and operator HMI. Front‑panel LED lamps offer real‑time per‑channel status indication for quick on‑site troubleshooting during commissioning or plant fault events. Built‑in transient‑suppression components absorb electrical spikes generated by inductive field loads, extending relay service life in noisy power‑plant cabinet environments.

Mechanical & Environmental Specifications

Part Number	3A99168G02
Module Type	QRO8 8‑Channel Relay Output Card, Q‑Line series
Channel Configuration	8 × Form‑A (SPST‑NO) relay outputs
Backplane Interface	Westinghouse Ovation Q‑Line proprietary bus
Form Factor	Standard plug‑in Eurocard for Q‑Line rack slots
Cooling Method	Natural convection cooling
Operating Temperature	0 °C ~ +60 °C, indoor control‑cabinet installation, non‑condensing
Coating Option	Conformal‑coated versions available for corrosive cabinet atmospheres

Primary Application Scenarios

This output module is widely deployed in fossil‑fuel power‑plant Ovation DCS cabinets. Typical field‑controlled assets include boiler soot‑blower solenoids, fan and pump auxiliary interlock relays, damper actuator on‑off commands, alarm annunciator triggers and safety‑related discrete control points. Plant maintenance teams procure this unit as a drop‑in replacement for aged boards suffering relay‑contact burnout, backplane connector wear or component‑level failure. It is also selected for brown‑field expansion projects to add discrete control points to existing Q‑Line racks without rack‑hardware replacement.

Important Technical Remarks

3A99168G02 works exclusively within Westinghouse Ovation Q‑Line rack architecture; it cannot be interchanged with non‑Q‑Line I/O hardware.
Verify exact part marking before purchase; different QRO revision variants are not always fully drop‑in compatible.
External field‑side load voltage must stay within relay‑contact rated limits; over‑voltage / over‑current loads will permanently damage relay channels.

Field Replacement & Acceptance Steps

Confirm exact part number 3A99168G02 and compatibility with target Q‑Line rack hardware revision.
Observe full ESD anti‑static handling procedures for populated circuit‑board assembly.
Perform lockout‑tagout procedures; fully de‑energize all external field‑load circuits before card removal or insertion.
Inspect backplane edge connector for bent pins, dust or corrosion prior to installing the replacement module.
Execute full channel functional test: trigger each output channel from Ovation HMI, confirm relay‑actuation status and physical field‑device response, verify diagnostic‑status reporting.

Closing Summary

Westinghouse 3A99168G02 QRO8 relay output module remains a mission‑critical legacy spare for Ovation Q‑Line DCS installations. It delivers galvanically‑isolated discrete on‑off control for power‑plant auxiliary‑equipment, supporting long‑term reliable operation of ageing distributed‑control‑system hardware.

Short Marketplace Listing Copy

Westinghouse 3A99168G02 Ovation Q‑Line QRO8 Relay Output Module
Westinghouse 3A99168G02 is an 8‑channel QRO8 relay output card built for Westinghouse Ovation Q‑Line DCS systems. Featuring eight Form‑A SPST‑NO galvanically‑isolated relay outputs for driving solenoids, interlock relays and field‑discrete loads. Front‑panel LED per‑channel status indicators, transient‑surge suppression for inductive loads. Widely used for thermal power‑plant DCS cabinet maintenance, spare‑part replacement and control‑point‑expansion retrofit jobs. Verify exact part‑number and Q‑Line rack compatibility before ordering. Complete per‑channel functional test shall be performed after installation.

SEO‑Optimized Bullet‑Point Block

Product: Westinghouse 3A99168G02 | Q‑Line QRO8 Relay Output Module

Plug‑in Eurocard relay output board, part number 3A99168G02 for Westinghouse Ovation Q‑Line DCS platform
8‑channel Form‑A SPST‑NO electromechanical relay outputs, full galvanic isolation between control logic and field circuits
Designed for switching solenoid valves, interlock relays, indicator lamps and other discrete plant‑field loads
Connects to Ovation controller via Q‑Line proprietary backplane bus; front‑panel LED channel‑status indication
On‑board transient‑surge suppression protects relays against inductive‑load electrical spikes
Natural‑convection cooling; operating temperature range: 0 °C ~ +60 °C for indoor DCS‑rack deployment
Key deployment: fossil‑fuel power‑plant DCS cabinets for boiler auxiliary‑equipment discrete‑control functions
End‑of‑OEM‑production critical spare for existing Q‑Line system maintenance and control‑point‑expansion retrofits
Mandatory exact‑part‑number validation; only compatible with Ovation Q‑Line rack infrastructure
ESD precautions and lockout‑tagout safety procedures required during module‑replacement work
Full‑channel output‑actuation functional validation test must be completed post‑installation