The IS200DRLYH1B is a Simplex Relay Output Terminal Board designed by General Electric (GE) for its Mark VI™ Control System. This board is the version within the DRLY series specifically intended for hazardous locations. It features a compact wall-mount design and provides the control system with 12 Form-C dry contact relay outputs. The IS200DRLYH1B board works in conjunction with the VCCC, VCRC, or VTUR processor board, connecting via a single 37-pin cable to control the 12 relay outputs.
The IS200DRLYH1B is one of two versions in the DRLY series. Compared to the H1A version, the H1B version has lower power relay contacts but is UL Class I, Division 2 certified for hazardous locations, making it suitable for industrial environments where explosive gases may be present. Each processor board can support two DRLY boards, providing a total of 24 relay outputs.
Key features of the IS200DRLYH1B include:
Hazardous Location Certification: UL Class I, Division 2 certified for specific hazardous environments.
12 Form-C Relays: Provides 12 double-pole double-throw dry contact relay outputs.
Series Contact Design: Each relay provides two normally open contacts in series, enhancing reliability.
Coordination with VCCC/VCRC/VTUR: Connects to the processor board via a single 37-pin cable.
LED Status Indication: A green LED indicates 28 V power status; a yellow LED for each relay indicates coil voltage.
No Relay State Monitoring: Unlike TRLY, DRLY has no onboard suppression and no relay state monitoring.
Default De-energized State: Relays default to a de-energized state when the control cable is unconnected.
Pluggable Terminal Blocks: High-density Euro-Block type terminal blocks are pluggable for easy on-site wiring and maintenance.
Wall Mounting: Mounts to a wall via four mounting holes in the corners of the metal support plate.
The board measures 21.59 cm long × 20.57 cm wide, suitable for installation in space-constrained control cabinets. It is important to note that the DRLY is not compatible with the PDOA I/O pack and does not have a shield terminal strip.
II. Main Functions
The primary functions of the IS200DRLYH1B include, but are not limited to, the following:
1. Relay Output Control
The IS200DRLYH1B board provides 12 Form-C dry contact relay outputs. Each relay is a double-pole double-throw type, containing two normally open contacts and two normally closed contacts. The two normally open contacts are wired in series, enhancing the reliability of contact opening. The relay coils have a nominal voltage of 24 V dc, powered by the 28 V dc supply from the VCCC, VCRC, or VTUR processor board.
2. Suitability for Hazardous Locations
The IS200DRLYH1B is UL Class I, Division 2 certified for hazardous locations, making it suitable for industrial environments where explosive gases may be present. Compared to the H1A version, the H1B has lower contact ratings but meets the safety requirements for hazardous locations.
3. LED Status Indication
The board features two types of LED indicators:
Green LED: Located at the top of the board, indicates the status of the 28 V dc power supply; lit during normal operation.
Yellow LEDs: One per relay, indicate whether voltage is present across the relay coil; lit when the coil is energized.
These indicators provide power and relay status information for field operation and maintenance personnel, facilitating rapid fault diagnosis.
4. Default De-energized State
When the control cable is not connected, all relays default to a de-energized state, ensuring the system is in a safe condition when unconfigured or during a fault.
5. Coordination with VTUR
Using the DTRT transition board, VTUR can control three relays on the DRLY. If two DTURs are used, six relays can be controlled.
6. No Onboard Suppression
Unlike the TRLY, the IS200DRLYH1B has no onboard relay suppression circuitry. Users must add appropriate external suppression circuits (such as diodes, varistors, etc.) based on the actual load to protect the relay contacts.
7. No Relay State Monitoring
The IS200DRLYH1B does not provide relay state monitoring. The VCCC or VCRC processor board cannot read the actual status of the relays; users must confirm relay operation through external means.
III. System Applications
1. Application in Mark VI Control System
The IS200DRLYH1B is a compact terminal board for discrete outputs within the Mark VI control system, particularly suitable for applications requiring hazardous location certification. Working with the VCCC, VCRC, or VTUR processor board, it provides a reliable relay output interface for the control system.
In the system, the IS200DRLYH1B plays the following roles:
Actuator Control: Controls field devices such as valves, motor starters, and indicators via relay contacts.
Alarm Output: Outputs alarm signals to a DCS or higher-level system.
Status Indication: Provides display of power and relay coil status via LEDs.
2. Differences from the H1A Version
The DRLY series has H1A and H1B versions, with the main differences as follows:
| Feature | H1A | H1B |
| Hazardous Location Certification | No | UL Class I, Division 2 |
| 28 V dc Contact Rating | 10 A | 2 A |
| 125 V dc Contact Rating | 0.5 A | 0.5 A |
| 120 V ac Contact Rating | 10 A | 1 A |
| 240 V ac Contact Rating | 3 A | 0.5 A |
| Operating Temperature | 0 to 60°C | 0 to 75°C |
The H1B version, while having lower contact capacity, is suitable for hazardous locations and has a wider operating temperature range.
3. Typical Application Scenarios
Petrochemical Industry: Controls field devices in hazardous locations such as refineries and chemical plants where explosive gases may be present.
Oil and Gas Extraction: Used for discrete control on offshore platforms and in natural gas processing plants.
Power Plants: Controls valves and motors in auxiliary systems for gas and steam turbines.
Water Treatment: Used for control in hazardous areas of wastewater treatment plants and waterworks.
Pharmaceutical Industry: Controls equipment in pharmaceutical facilities where flammable solvents may be present.
IV. Detailed Interface Description
1. Terminal Blocks
The IS200DRLYH1B uses pluggable high-density Euro-Block type terminal blocks for connecting external wiring for the 12 relay outputs. The terminal blocks plug into numbered receptacles on the board. Wires for the 12 relay outputs are connected directly to the odd-numbered screws on the terminal blocks.
2. Ground Terminal
Two screws on TB2 are provided for the SCOM (chassis ground) connection. These must be connected to chassis ground using the shortest possible wire. Note: The board does not have a shield terminal strip.
3. Connector
The board connects to the VCCC, VCRC, or VTUR processor board via a single 37-pin D-type connector. This cable is identical to those used on the TRLY terminal board, facilitating spare parts management.
4. LED Indicators
| LED | Color | Location | Description |
| Power LED | Green | Top of board | Indicates 28 V dc power status; lit during normal operation |
| Relay LEDs (12) | Yellow | Near each relay | Indicate coil voltage for the corresponding relay; lit when coil energized |
V. Diagnostics and Maintenance
1. Diagnostic Functions
The diagnostic functions of the IS200DRLYH1B are relatively limited:
| Diagnostic Item | Description |
| Power Status Indication | Green LED indicates whether the 28 V dc power supply is normal. |
| Coil Voltage Indication | Yellow LEDs indicate whether voltage is present on each relay coil. |
| ID Chip Verification | A read-only ID chip on the connector stores the board's serial number, type, and revision number. It is read by the VCCC/VCRC/VTUR; a mismatch generates a hardware incompatibility fault. |
Note: The IS200DRLYH1B does not provide relay state monitoring. The processor board cannot read the actual contact status of the relays.
2. Common Troubleshooting
| Fault Symptom | Possible Cause | Troubleshooting Suggestions |
| Green LED not lit | 28 V power failure, disconnected cable | Check processor board power, check connection cable |
| Yellow LED lit but relay does not operate | Relay failure, stuck contacts | Replace board, test relay |
| Relay operates but external device does not respond | External power failure, wiring error, burned contacts | Check external power and wiring, measure contact continuity |
| Hardware incompatibility fault | ID chip information mismatch | Verify correct board model, contact GE technical support |
3. Maintenance Recommendations
Periodic Inspection: Check that terminal blocks are securely plugged in and wires are not oxidized.
Cleaning: Regularly clean the board to prevent dust accumulation affecting heat dissipation and insulation.
ESD Protection: Wear a grounding strap when handling the board and store it in anti-static bags.
Contact Protection: Add appropriate external suppression circuits (diodes, varistors, etc.) based on the load type to extend contact life.
Spare Parts Management: Maintain a spare IS200DRLYH1B board to reduce downtime in case of failure.
VI. Installation and Configuration
1. Installation Steps
Locate Mounting Holes: Mark the positions of the four mounting holes at the corners of the metal support plate on the wall.
Secure Board: Fasten the IS200DRLYH1B board to the wall using screws through the four mounting holes.
Connect Relay Outputs: Connect the external wires for the 12 relay outputs to the odd-numbered screws on the terminal blocks.
Insert Terminal Blocks: Plug the wired terminal blocks into the corresponding numbered receptacles on the board.
Ground Connection: Connect the two screws on TB2 to chassis ground using the shortest possible wire.
Connect Cable: Connect the 37-pin cable to the board and to the VCCC/VCRC/VTUR processor board.
Verify Installation: Confirm all connections are secure.
2. Configuration Method
The IS200DRLYH1B board has no jumpers or hardware settings. All configuration is done via software on the VCCC, VCRC, or VTUR processor board.
