Description
The Schneider Electric STBDDI3725KS is a 16-channel basic digital input kit belonging to the Modicon STB distributed I/O hardware platform. This kit acts as an interface between field sensors and a Network Interface Module (NIM) by converting discrete 24 V DC signals into logic data for the control bus. The kit includes the STBDDI3725 module, the STBXBA3000 mounting base, and the STBXTS1180 18-terminal screw connector block.
Commercial and Lifecycle Status
- Condition: New Original / Factory Sealed or New Surplus
- Warranty: 12-Month Warranty
- Availability: In Stock / Available via distribution pipelines
- Lead Time: Standard processing is 1–2 business days.
- Lifecycle Notice: Schneider Electric indicates a standard commercial transition phase for this product family. Verify long-term lifecycle roadmap documentation or contact us directly for contract-specific pricing and migration options.
- Pricing Note: Displayed pricing is subject to fluctuations in supply and raw material components; request a firm quote for targeted procurement.
Technical Specifications
| Parameter | Value / Specification |
| Manufacturer | Schneider Electric |
| Product Range | Modicon STB Distributed I/O |
| Part Number / Kit ID | STBDDI3725KS |
| Kit Composition | STBDDI3725 module, STBXBA3000 base, STBXTS1180 screw block |
| Number of Inputs | 16 |
| Input Type / Standard | IEC 61131-2 Type 3 |
| Discrete Input Voltage | 24 V DC nominal |
| Input Logic | Positive (Sink input, sourcing sensor) |
| Voltage Range (State 1) | 15 to 30 V DC |
| Voltage Range (State 0) | −3 to 5 V DC |
| Input Current (State 1) | \ge 2.5 mA |
| Input Current (State 0) | \le 1.5 mA |
| Nominal Input Current | 4.5 mA at 24 V DC |
| Hardware Response Time | 2 ms (Off-to-On) / 2 ms (On-to-Off) |
| Input Filtering | 1 ms hardware low-pass |
| Internal Bus Consumption | 100 mA at 5 V DC for logic bus |
| Isolation Voltage | 1500 V AC for 1 minute between channels and logic bus |
| Hot-Swapping Capable | Yes (supported under basic NIM automation configurations) |
| Operating Temperature | −25 to +70 °C without derating |
| Ingress Protection | IP20 conforming to EN 61131-2 Class 1 |
System Integration and Wiring Architecture
Input Mechanics & Groupings
The 16 channels are divided internally into distinct diagnostic groups. The input circuits conform to IEC 61131-2 Type 3 standards, consuming less current at nominal voltage (4.5 mA) than older Type 1 inputs, which reduces overall thermal dissipation within high-density control cabinets.
Connection Topologies
Field wiring terminates directly onto the STBXTS1180 18-position screw terminal block. The terminal allocation distributes power across four independent sensor power groups to simplify two-wire and three-wire sensor connections:
- Pins 1, 3, 5, 7: Sensor power group 1 (+) for inputs 1 through 8.
- Pins 2, 4, 6, 8: Discrete sensor inputs 1 through 4.
- Pins 10, 12, 14, 16: Sensor power group 2 (+) for inputs 5 through 8.
- Pins 9 & 18: Sensor power return lines (PDM−) dedicated to 3-wire proximity sensors.
Power Distribution and Base Assembly
The module relies on an upstream Power Distribution Module (PDM) such as the STBPDT3100 or STBPDT3105 to source field-side terminal voltage. The STBXBA3000 base routes both the 24 V DC field bus power and the 5 V DC logic bus across the island backplane.
Installation Guidelines & Best Practices
- Backplane Alignment: Snap the STBXBA3000 base onto a 35 mm symmetric DIN rail before sliding the STBDDI3725 module into place. Ensure the side-interlocking tabs fully connect with adjacent bases to avoid data transmission faults across the internal logic bus.
- Hot-Swapping Constraints: While the basic module supports hot-swapping under a running Network Interface Module, do not disconnect the 18-pin terminal block under active inductive load conditions to avoid terminal arcing or damage to internal optocouplers.
- Fuse Protection: Protect the field power loops via a time-lag 5 A integrated fuse located inside the primary upstream PDM. Ensure total current across all 16 sensors does not exceed the distribution rating of the PDM slice.
