The DI840 is a 16-channel, 24 V DC digital input module designed for single or redundant applications within the ABB Ability™ System 800xA®. This module is engineered for high-reliability digital signal acquisition in industrial automation environments, featuring advanced diagnostics, Sequence of Event (SOE) recording, and flexible sensor power management capabilities.
Each input channel of the DI840 module includes current-limiting components, Electromagnetic Compatibility (EMC) protection elements, an input status indicator LED, and an optical isolation barrier, ensuring stable operation and electrical safety in demanding industrial settings. The module supports various Mounting Termination Units (MTUs), accommodating different field wiring requirements, including standard, compact, extended, and redundant configurations.
This module is widely used in process control, power monitoring, manufacturing automation, and other fields requiring high-precision event timestamping, reliable status monitoring, and flexible networking.
II. Product Features and Benefits
1. Self-Diagnostics
The DI840 module features cyclic self-diagnostics, covering:
Process Power Supply Supervision and Transducer Over-Current Supervision: Reported as "External Channel Error," with a detection time ≤ 500 ms.
Internal Channel Circuitry Testing: Tested with patterns, with errors reported as "Internal Channel Error," detection time ≤ 100 ms.
Common Test Function Errors: Reported as "Module Error," with a detection time of 12 ms.
2. Sequence of Events (SOE)
The DI840 supports high-precision Sequence of Events recording, featuring:
An event queue capable of holding up to 257 events.
Event messages that can report channel value, queue full, synchronization jitter, uncertain time, shutter filter active, and channel error statuses.
Event timestamp resolution of 1 ms, with an accuracy of -0 ms / +1.3 ms.
3. Digital Filtering Function
The module provides configurable digital filtering, with filter times selectable from 0 to 127 ms, used to suppress pulses shorter than the set time, ensuring signal stability and noise immunity.
4. Shutter Filter
The module integrates a Shutter Filter for filtering out unwanted disturbance events, with configurable parameters:
Shutter Period: 2 to 170 seconds
Shutter Trigger: 4 changes
Recovery Time: 0 to 682 seconds
5. Sensor Power Supply and Protection
One output per two input channels provides sensor power, with a maximum output of 40 mA and a short-circuit current limit of 60 mA.
The supply features supervision and current limiting, enhancing system reliability.
6. Status Indication
The module front features comprehensive LED indicators, including:
F (Fault), R (Run), W (Warning)
16 individual channel status LEDs
Status indication for Module Error, Module Warning, Channel Error, etc.
III. Mounting Termination Unit (MTU) Types and Application Scenarios
The DI840 supports various MTU types to suit different wiring methods and application needs:
1. MTUs for Single Applications
Extended MTU (e.g., TU830/TU833): Supports three-wire connection to sensors without additional terminals.
Compact MTU (e.g., TU810/TU814): Provides terminals for process voltage supervision inputs but requires external terminals for distributing process power to sensors.
TU818 Compact MTU: Provides connection to two-wire sensors without external marshaling.
TU838 Extended MTU: Provides a fuse (3 A max.) per two channels for process power output protection.
TU812 Compact MTU: Features a D-Sub 25-pin (male) connector for process connection, suitable for space-constrained cabinets.
2. MTUs for Redundant Applications
IV. Detailed Technical Parameters
Electrical Parameters
Input Characteristics: Supports current-sinking inputs, compatible with common PLC and DCS system interfaces.
Power Supply Adaptability: Wide operating voltage range (19.2–30 V), tolerant to industrial voltage fluctuations.
Noise Immunity: Good common-mode noise rejection, supports long-distance cable transmission (up to 600 meters).
Mechanical and Environmental Suitability
Compact Design: Module width is only 45 mm, suitable for high-density cabinet installation.
Wide Operating Temperature Range: Supports 0 to +55 °C; some certifications specify +5 to +55 °C.
Protection and Safety: Conforms to IP20 protection class for installation inside control cabinets; holds multiple certifications including CE, cULus, ATEX Zone 2, and marine certifications (BV, DNV, LR).
Electromagnetic Compatibility
Reliability and Lifespan
Utilizes industrial-grade components and optical isolation design for long-term stable operation.
Features comprehensive diagnostics and status feedback, supporting predictive maintenance and rapid fault localization.
V. Installation and Connection Guide
The DI840 module must be used with the corresponding MTU. Specific wiring methods vary depending on the MTU type. Examples include:
TU830/TU833: Suitable for three-wire sensors, with simple wiring and no extra terminals needed.
TU810/TU814: Suitable for applications requiring process power supervision; external power distribution terminals are required.
TU812: Integrates signals and power via a D-Sub connector, suitable for cabinets with space constraints.
TU838: Features independent fuses per two channels, suitable for applications requiring branch protection.
TU842/TU843/TU852: Designed for redundant systems, supporting hot-swap and seamless switching.
For detailed wiring diagrams, please refer to the "DI840 Process Connections" table and corresponding figures in the product manual.
VI. Environment and Certifications
The DI840 complies with numerous international standards and industry certifications, including:
Electrical Safety: EN 61010-1, UL 61010-1, EN 61010-2-201, UL 61010-2-201
Hazardous Location: Class I Div 2 cULus, Class I Zone 2 cULus, ATEX Zone 2
Marine Certifications: BV, DNV, LR
Environmental Suitability: Operating temperature 0 to +55 °C, Storage temperature -40 to +70 °C, Protection class IP20
Environmental Compliance: RoHS (DIRECTIVE/2011/65/EU) and WEEE (DIRECTIVE/2012/19/EU)
VII. Compatibility and System Integration
The DI840 integrates seamlessly into the ABB System 800xA® control system and is compatible with:
Controllers: AC 800M series
Communication Networks: ModuleBus, Control Network
Engineering Tools: Control Builder M, 800xA System Configuration Tools
MTU Compatibility: Full range of S800 I/O Mounting Units
