Description
System Architecture & Operational Principle
The IS200ERSCG1A is a Relay Output Board (ERSG) in the GE Mark VI Speedtronic family, designed to mount in a Mark VI I/O rack (Purdue Level 1). It serves as a critical interface between the Mark VI main controller and high-current field devices, converting low-power digital signals from the VME backplane into robust relay closures for actuation.
The board contains 16 independent Form C (SPDT) electromechanical relays, each capable of switching up to 10 A at 250 VAC or 30 VDC. These relays are used to control fuel shutoff valves, generator circuit breakers, pump motors, and alarm annunciators in turbine systems. The board also includes 1500 VDC optical isolation between the VME backplane and relay contacts, preventing ground loops and protecting the Mark VI controller from field-side transients.
In a typical gas turbine application, the IS200ERSCG1A receives digital commands from the Mark VI controller (e.g., “open fuel valve,” “trip generator”) and energizes the corresponding relay. The relay contacts then close, supplying power to the field actuator. The board’s status LEDs provide visual feedback for each relay’s state (energized/de-energized), aiding in diagnostics.
The IS200ERSCG1A is hot-swappable when installed in a supported Mark VI rack, allowing replacement without shutting down the turbine—a critical feature for 24/7 power generation and petrochemical applications.
Core Technical Specifications
-
Physical Interface: 2x 20-pin terminal blocks (10 relays per block) for field wiring; 96-pin VME backplane connector (P1/J1)
-
Output Channels: 16 Form C (SPDT) electromechanical relays
-
Contact Rating: 10 A @ 250 VAC resistive, 10 A @ 30 VDC resistive, 5 A @ 250 VAC inductive
-
Isolation: 1500 VDC relay-to-VMEbus, 500 VDC relay-to-relay
-
Operating Temperature: -40°C to +70°C (-40°F to +158°F)
-
Storage Temperature: -55°C to +85°C (-67°F to +185°F)
-
Humidity: 5–95% RH non-condensing
-
Backplane Compatibility: Mark VI VME rack (P1/J1 interface)
-
Power Consumption: 8 W typical, 12 W max (depends on relay load)
-
Dimensions: ~240 mm × 30 mm × 180 mm (9.4 in × 1.2 in × 7.1 in)
-
Weight: ~1.0 kg (2.2 lbs)
-
Certifications: UL/cUL, CE, IEEE 1613 (substation environmental compliance)
GE IS200ERSCG1A
Customer Value & Operational Benefits
High-Current Drive for Critical Actuators
The 10 A relay rating allows the IS200ERSCG1A to directly control high-power field devices (e.g., fuel valves, motor starters) without external interposing relays. This simplifies system design, reduces component count, and lowers installation costs.
Robust Isolation for Harsh Environments
1500 VDC isolation between the VME backplane and relay contacts prevents ground loops and protects the Mark VI controller from voltage spikes caused by lightning, motor startups, or faulty actuators. This is essential in outdoor substations or refinery environments with high electrical noise.
Hot-Swappable Maintenance Without Downtime
The ability to replace a faulty IS200ERSCG1A without powering down the rack is invaluable for continuous process industries. Maintenance can be performed during scheduled outages or routine checks, avoiding costly turbine trips or safety incidents.
Field Engineer’s Notes (From the Trenches)
When troubleshooting a IS200ERSCG1A, always check the terminal block connections first—loose or corroded contacts are a common cause of intermittent relay operation. I once spent hours chasing a “stuck valve” fault only to find a wire nut had loosened on the relay output. Also, verify the relay coil current draw—if the load exceeds 10 A, the relay contacts will overheat and fail prematurely. Use external contactors for loads above the relay rating.
Real-World Applications
In a Georgia natural gas power plant, the IS200ERSCG1A controls 16 field devices on a 300 MW turbine, including fuel shutoff valves, generator circuit breakers, and alarm horns. The 1500 VDC isolation prevents interference from nearby high-voltage breakers, while the hot-swap capability allows maintenance during plant outages without interrupting turbine monitoring.
On a Louisiana refinery, the IS200ERSCG1A interfaces with hydraulic pump motors on a steam turbine driver. The board’s wide operating temperature range (-40°C to +70°C) withstands the refinery’s hot control room, and its 10 A relay rating eliminates the need for external contactors in most pump applications.
