EMERSON 2840A79G03 20VDC QBO Logic Output DCS Card

June 05, 2026

EMERSON 2840A79G03 20VDC QBO Logic Output DCS Card

It is the third-generation revised QBO isolated digital output card, the latest upgrade version of 2840A79G01/G02, specially customized for low-current field logic drive of QSD servo cabinet, matched with servo power board 2840A78G01 to build full servo control rack for thermal power boiler/turbine servo valve interlock control.

Description

PN：2840A79G03｜Alias：6QBO13、3A99162G03，Brand：Westinghouse（Emerson Ovation DCS Q-Line 系列）

Different from G01/G02 high-current drive type, G03 is designed for 20VDC low-power logic output, mainly used for small signal relay, servo board internal logic interlock, indicator lamp drive, widely applied in power plant DCS servo control cabinet, petrochemical auxiliary interlock control, pulp & paper process control cabinet.

Optimized full-stage EMC filter + surge absorption circuit, PCB full conformal coating for high-humidity & strong electromagnetic interference power plant cabinet environment, pin definition fully compatible with G01/G02, direct plug-and-play interchange on original Ovation rack slot.

Main Application

QSD servo rack internal interlock logic output (match 2840A78G01 servo power supply)
20VDC small relay, signal indicator, optocoupler drive for boiler/turbine auxiliary interlock
Low-current field switching control of small solenoid valves in DCS control cabinet

二、Electrical Technical Parameters（电气规格）

1.Field Output Rating（现场输出）

Rated working load voltage：20VDC（fixed design for G03, not 60VDC like G01/G02）
Single channel rated output current：16mA/CH max（low-current logic dedicated）
Total module maximum load current：≤320mA
Output type：Isolated open collector sinking output, with channel flash indication function (unique G03 feature)

2.Backplane Power Supply

3.Isolation & Protection

Channel vs backplane reinforced isolation：≥1000VAC
Per-channel independent over-current & short-circuit lockout protection, built-in TVS surge suppressor + multi-stage RC filter (enhanced vs G02)
Front panel LED: Power OK / Channel ON / Channel fault / short circuit alarm indication, individual flashing alarm for faulty channel

4.Ambient Environment

Operating Temp：0℃ ~ +60℃（cabinet indoor installation）
Storage Temp：-40℃ ~ +85℃
Humidity：5%~95%RH non-condensing, PCB full three-proof coating

三、Mechanical Specifications（机械尺寸）

Overall dimension：L133mm × W82mm × H16mm（same outline as G01/G02，通用安装尺寸）
Net weight：≈375g
Mount：Standard Ovation Q-series rack hot-swap plug-in, compatible original cabinet slot; optional DIN transition base installation
Wiring：Side terminal block for field wiring, gold-plated rear edge connector for rack backplane docking
Housing：Flame retardant black ABS shell with heat dissipation slots

四、Key Difference vs G01/G02（三代型号区分）

Part No.	Rated Voltage	Single Channel Current	Core Application
2840A79G01	Max60VDC	0.5A/CH	Large relay, solenoid high-current drive
2840A79G02	Max60VDC	300mA/CH	Medium load field valve + filter upgrade
2840A79G03	Fixed20VDC	16mA/CH	Servo cabinet internal small logic, signal lamp drive（低电流专用）

五、Datasheet Core Feature

Unique channel flashing fault diagnosis (only G03 supports flashing prompt for abnormal channel)；
Full-board enhanced anti-interference circuit, for high EMI servo cabinet harsh working condition；
100% pin-compatible with G01/G02, one-to-one replacement without program modification；
CE certified, original US-made Ovation DCS spare part.

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