The 216DB61 is a core Binary Input and Tripping Output Unit within the ABB REG 216 numerical generator protection system. It is a highly integrated and critical multi-functional I/O module that plays a dual role in the protection system: it is responsible for acquiring external binary signals (e.g., block, interlock, status signals), and it executes trip commands issued by protection functions, directly driving tripping relays. Its design focuses on reliability, safety, and flexibility, ensuring that protection commands are executed accurately and without delay, while also providing the necessary logic input interface for the system.
This plug-in unit is installed in the 216MB66 or 216MB68 standard equipment racks of the REG 216 system and is an indispensable part of a complete protection scheme. It is widely used in protection systems for generators, large motors, transformers, and feeders.
2. Core Functions
The 216DB61 unit integrates 16 binary input channels and 8 tripping output channels. Its functions can be clearly divided into two main categories:
1. Binary Input Function
Channel Capacity: Provides 16 binary input channels (CHI01 to CHI16).
Signal Acquisition: Receives electrically isolated external dry contact signals from the 216GE61 Input Relay Unit. These signals typically represent:
Blocking Signals: Manual or automatic blocking of certain protection functions.
Interlock Signals: Operational condition judgments from other systems or devices.
Status Signals: Remote position indications for circuit breakers, disconnectors, etc.
Enable/Disable Signals: Status of function enable/disable switches.
Signal Transmission: Transmits the acquired external binary statuses in real-time to the 216VC62a Processing Unit via the B448C parallel bus for use by protection logic and control systems.
2. Tripping Output Function
Channel Capacity: Provides 8 independent tripping output channels (CHO01 to CHO08).
Command Execution: Receives trip commands from the 216VC62a processing unit (via the B448C bus) and drives its internal output stages, which in turn control the high-capacity tripping relays in the 216GA62 Tripping Relay Unit.
Safety Design: The tripping output channels are the final execution stage of the protection system. Their design ensures high reliability and includes comprehensive channel enable and block mechanisms to prevent maloperation.
3. Advanced Control Functions
Enable and Block: The unit features a unique hardware-level enable and block logic, implemented via four special input channels CHI13 to CHI16:
Enable 1 and Enable 2: These two inputs (CHI13, CHI14) form an AND logic. All 8 tripping output channels are only permitted to operate if both of these inputs are energized (logic "1"). This is typically used for confirming system operating conditions, e.g., "control power healthy" and "system not under maintenance command".
Block 1 and Block 2: These two inputs (CHI15, CHI16) form an OR logic. If either one is energized (logic "1"), all 8 tripping output channels are immediately blocked, regardless of protection operation. This is used for emergency shutdown, maintenance isolation, or block commands from higher-priority systems.
Output Driver Monitoring: The unit continuously monitors the status of the 8 tripping output channel drivers. If a fault such as a short circuit is detected in a driver, the unit automatically blocks the entire channel group to which the faulty driver belongs (channels are divided into two groups: 1/3/5/7 and 2/4/6/8) and raises an alarm, implementing a fail-safe principle.
3. Working Principle
The operation of the 216DB61 unit is a collaborative process involving hardware, software, and bus communication. Its signal flow and logic decision process are as follows:
1. Binary Input Signal Flow
Step 1: Signal Connection. External field binary signals (e.g., DC 110V/220V) are first fed into the 216GE61 Input Relay Unit, driving its internal auxiliary relays K1-K16. The dry contacts of these relays provide electrical isolation for the connection to the 216DB61 unit.
Step 2: Signal Acquisition. The status of the 216GE61 relay contacts is connected via standard cable to the upper connector ("a") of the 216DB61 unit, corresponding to input channels CHI01 to CHI16. The input register inside the 216DB61 scans and latches the status of these channels.
Step 3: Bus Transmission. The latched input statuses are periodically placed on the B448C parallel bus via the unit's bus interface.
Step 4: Logic Processing. The 216VC62a Processing Unit reads these input statuses from the bus and, according to the logic pre-configured in the software (e.g., set in the 'Edit Binary Channels' menu), assigns these external signals to the relevant protection functions for blocking, interlocking, triggering, or as conditions for logic operations.
2. Tripping Output Signal Flow
Step 1: Command Generation. When a protection function (e.g., differential protection, overcurrent protection) within the 216VC62a processing unit activates and meets the trip condition, it generates a trip command.
Step 2: Bus Publication. This trip command is sent as a data packet via the B448C bus.
Step 3: Command Reception & Enable Check. The 216DB61 unit receives the trip command from the bus. Before the command is executed, the unit first checks the status of the hardware Enable and Block logic:
It reads the status of CHI13 and CHI14 to determine if the "Enable" condition is met (both are "1").
It simultaneously reads the status of CHI15 and CHI16 to determine if the "Block" condition is active (either one is "1").
The trip command can only proceed if the "Enable" condition is met AND the "Block" condition is NOT active.
Step 4: Output Drive. Upon passing the logic check, the output register inside the 216DB61 unit sets the corresponding tripping channel, and the output driver stage activates, producing an output signal.
Step 5: Relay Action. This output signal is transmitted via the lower connector ("b") to the 216GA62 Tripping Relay Unit, driving the corresponding high-capacity, high-reliability tripping relay. The contacts of this relay ultimately close the trip coil circuit of the switching device, causing the circuit breaker to open.
3. Key Features & Safety Mechanisms
Hardware-Level Safety: The Enable and Block functions are implemented via the BR1 jumper on the unit's PCB and internal hardware logic, independent of correct software execution. This provides a higher level of safety, preventing maloperation due to software crashes or processor faults.
Fail-Safe Design: The output driver monitoring ensures that if a fault occurs in the output circuit itself, the system automatically blocks and alarms, preventing failure to operate or maloperation, and localizing the fault impact.
Flexible Configuration: Via the BR1 jumper, the user can decide whether to enable the Enable/Block function for CHI13-CHI16. If not required, these channels can be used as ordinary binary inputs. The mapping of all I/O channels to specific protection functions is configured via software using a portable user interface (PC) connected to the 216VC62a, offering great flexibility.
4. Hardware Design & Interfaces
5. Configuration & Settings
Hardware Jumper Setting: The BR1 Jumper on the PCB is the key setting.
Software Configuration: Performed via a portable PC connected to the 216VC62a interface, using the operator program:
Assign Tripping Channels: Map specific protection functions (e.g., "87G", "51V") to specific tripping output channels of the 216DB61 (e.g., CHO01).
Define Binary Inputs: Name each binary input channel, set debounce time, and specify it for event recording.
6. Self-Diagnostics & Maintenance
The 216DB61 unit features comprehensive self-diagnostics and reports detailed fault information via its device status register:
Monitored Items: Internal 5V supply, output driver stage faults, tripping relay module supply, data communication errors, etc.
Fault Indication: Any fault lights the red AL LED on the front panel and triggers a remote alarm via the system bus.
Event Logging: All status changes and fault information are recorded in the event list of the 216VC62a processing unit, facilitating fault analysis.
Maintenance Operation: Before plugging/unplugging the unit or performing any internal work, safety regulations must be followed by switching off the auxiliary supply to the rack.
7. Application Scenarios
The 216DB61 is ideally suited for the following applications:
Generator Protection: Serves as the trip output for main protection (e.g., differential) and backup protection (e.g., overcurrent, earth fault).
Large Motor Protection: Executes trip commands for faults like overload, stall, and short circuit.
Transformer Protection: Used for tripping based on differential, Buchholz, pressure relief, etc.
Feeder Protection: Acts as the execution unit for line protection.
Any tripping circuit requiring high reliability and external hard-wired blocking capability.
