Product Overview
The Schneider Electric 990NAD23000 is a specialized IP20-rated Modbus Plus (MB+) junction box with integrated line terminal, designed as a critical passive infrastructure component for building and maintaining reliable Modbus Plus industrial networks. Part of Schneider Electric’s Modicon automation platform connection accessories, the 990NAD23000 serves as a professional, centralized physical connection point—or “T-tap”—for joining devices onto a Modbus Plus trunk cable. Unlike active repeaters or bridges, the 990NAD23000 is a fully passive device that requires no external power supply, functioning purely at the electrical layer to preserve signal integrity across the network.
In a Modbus Plus network—a deterministic, token-passing peer-to-peer network operating at 1 Mbps and widely deployed to interconnect Modicon Quantum, Premium, Momentum, and TSX Micro PLCs, I/O modules, drives, HMIs, and gateways—the 990NAD23000 provides the essential three-way connection: trunk cable in, trunk cable out, and a device drop. This topology allows a new node to be added to the network without cutting, splicing, or otherwise disturbing the main shielded trunk cable. The junction box houses high-quality screw terminals for all three connections, a built-in switchable 120-ohm terminating resistor for proper impedance matching at segment endpoints, and a corrosion-resistant light-grey enclosure. By replacing unreliable “vampire taps” and field-made twisted splices with a robust, maintainable, code-compliant connection point, the 990NAD23000 directly improves communication stability, simplifies troubleshooting, and reduces unplanned downtime across the entire control system.
Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | 990NAD23000 |
| Manufacturer | Schneider Electric (Modicon) |
| Product Type | IP20 Modbus Plus Junction Box with Line Terminal |
| Product Category | Connection Accessory |
| Network Protocol | Modbus Plus (MB+), 1 Mbps token-passing |
| Topology / Function | Passive 3-way T-tap (trunk in / trunk out / device drop) |
| Termination | Integrated switchable 120 Ω line termination resistor |
| Termination Method | Jumper- or DIP-switch configurable |
| Connector Type | Screw terminal blocks (3-way: trunk in, trunk out, drop) |
| Number of Ways | 3 |
| Cable Compatibility | Belden 9841 / 9842 or equivalent shielded twisted pair (STP) |
| Power Requirement | Passive device — no external power required (0 W) |
| Enclosure Protection | IP20 (IEC 60529) |
| Enclosure Material | Corrosion-resistant ABS plastic, light grey |
| Mounting | DIN rail or panel / wall mount |
| Wire Tool Required | Schneider P/N 043509383 |
| Compatible Platforms | Modicon Quantum, Modicon Premium, Modicon Momentum, Modicon TSX Micro |
| Certifications | CE, UL / cUL Listed, RoHS compliant |
| Operating Temperature | 0°C to +60°C |
| Storage Temperature | -40°C to +85°C |
| Relative Humidity | 5% to 95% RH, non-condensing |
| Quantity per Set | 1 piece |
| Contractual Warranty | 18 months |
| Net Weight | 0.23 kg (0.51 lb) |
| Dimensions (H × W × D) | 26 × 55 × 114 mm (1.02 × 2.17 × 4.49 in) |
| GTIN | 00785901799146 |
| Country of Origin | CN (China) |
| Lifecycle Status | Normally stocked; Green Premium status: Not Green Premium (RoHS will not be compliant) |