Product Overview
The ABB DI825 is an 8-channel, 125 V DC digital input module engineered for the S800 I/O system. It accepts input voltages from 71 to 156 V for logic "1" and 0 to 20 V for logic "0", with a typical input current of 3.0 mA at 125 V. Each channel is individually isolated, providing robust performance in electrically noisy industrial environments.
Every input channel integrates current limiting, EMC protection, an input status LED, and an optical isolation barrier. Channels 1 and 8 can serve as voltage supervision inputs for their respective groups (channels 2–4 and 5–7). If the supervised voltage disappears, the module sets a channel error and activates the Warning LED, readable via the ModuleBus.
Technical Specifications
| Parameter |
Value |
| Article Number |
3BSE036373R1 |
| Type |
Digital Input |
| Signal Specification |
125 V d.c. |
| Number of Channels |
8 |
| Signal Type |
Current sinking |
| Input Voltage Range ("0") |
0 – 20 V |
| Input Voltage Range ("1") |
71 – 156 V |
| Input Impedance |
41.5 kΩ |
| Isolation |
Individually isolated channels |
| Filter Times (digital, selectable) |
0 – 100 ms |
| Maximum Field Cable Length |
600 meters (656 yards) |
| Event Recording Accuracy |
-0.25 ms...1.0 ms |
| Event Recording Resolution |
0.4 ms |
| Rated Insulation Voltage |
250 V |
| Dielectric Test Voltage |
2300 V a.c. Ch–Ground, 1350 V a.c. Ch–Ch |
| Power Dissipation |
Max. 4.9 W |
| Current Consumption +5 V Modulebus |
Max. 90 mA |
| Current Consumption +24 V Modulebus |
0 |
| Current Consumption +24 V External |
0 |
| Dimensions (W x D x H) |
45 mm x 102 mm (111 mm with connector) x 119 mm |
| Weight |
0.14 kg (0.31 lbs.) |
Key Features & Benefits
- 8 channels for 125 V d.c. inputs
- Individually isolated channels for superior noise immunity
- Input status indicators for quick diagnostics
- Sequence of Event (SOE) functionality with high-resolution timestamping
- Selectable digital filtering to suppress transients
- Process voltage supervision via channels 1 and 8
- Compatible with multiple MTUs: TU811, TU813, TU831, TU839, TU851
Industry Applications
The ABB DI825 excels in high-voltage sensing applications across process industries. Its 125 V DC input range and individual isolation make it ideal for monitoring relay contacts, limit switches, and control signals in power distribution, chemical processing, and water treatment plants. The SOE capability allows precise event logging for post-incident analysis, reducing downtime and improving system reliability.
In a typical power substation, the DI825 can supervise breaker status and alarm signals. The voltage supervision feature ensures that even if a sensor supply fails, the module flags the affected channels immediately, enabling rapid response.
Installation & Setup
Mount the ABB DI825 onto a standard S800 I/O rail and connect it via the appropriate MTU (e.g., TU811V1). Ensure the field wiring is terminated correctly: current sinking inputs require a common positive supply. Use shielded cables for long runs (up to 600 meters) to minimize electromagnetic interference. Configure the digital filter times via the control system to match your signal characteristics.
For voltage supervision, connect the process voltage to channel 1 or 8 and set the corresponding group supervision in the configuration software. Verify the ModuleBus connection and power supply (+5 V, max 90 mA) before energizing the field inputs.
Maintenance & Reliability
Routine maintenance is minimal. Periodically inspect the module for dust accumulation and ensure the ambient temperature stays within 0 to +55 °C (32 to +131 °F). The module's EMC protection (EN 61000-6-4 and EN 61000-6-2) and dielectric isolation (2300 V a.c.) ensure long-term reliability in harsh environments. Check the front LEDs (Fault, Run, Warning, and channel status) during startup to confirm proper operation.
Compatibility & Integration
The ABB DI825 is part of the ABB S800 I/O family, seamlessly integrating with ABB AC 800M controllers and other systems via the ModuleBus. It works with MTUs TU811, TU813, TU831, TU839, and TU851. The module supports HART (No) and is not redundant, high-integrity, or intrinsically safe, making it suitable for general-purpose industrial automation.
Selection Guide & Purchasing Advice
Before purchasing, verify the DI825's compatibility with your existing MTU and controller. Confirm the power supply specifications (5 V Modulebus, max 90 mA) and the environmental requirements (IP20, pollution degree 2). For high-voltage applications, ensure the field wiring meets the rated insulation voltage of 250 V. PLC Source PRO offers genuine ABB DI825 modules with fast worldwide shipping.