Description:
The Allen-Bradley 1794-OB16PXT is a 16-point, 24V DC sourcing (PNP) digital output module from the FLEX I/O-XT series, specifically engineered for harsh industrial environments. It features electronic per-point protection (short-circuit and overload), a conformal coated PCB for resistance to humidity and contaminants, and an extended operating temperature range of -20°C to +70°C. Designed for DIN rail mounting with removable terminal bases, it provides reliable control for actuators, solenoid valves, and indicators in demanding applications like mining, metals, and outdoor installations.
Application Scenarios:
In a Taiyuan-based steel mill’s descaling water pump station, control cabinet temperatures often spike in summer, and conductive iron oxide dust is pervasive. The plant replaced standard I/O modules with the 1794-OB16PXT due to its extended temperature rating and conformal coating. When a field valve coil shorted, the module’s electronic protection instantly shut down the single channel without blowing a fuse or disrupting the other 15 pumps, allowing maintenance to replace the faulty valve during a scheduled break without a full station shutdown.
Parameter:
| Main Parameters | Value/Description |
|---|---|
| Product Model | 1794-OB16PXT |
| Manufacturer | Rockwell Automation (Allen-Bradley) |
| Product Series | FLEX I/O‑XT (Extended Temperature/Tough) |
| I/O Type | Digital Output (DO) |
| Number of Points | 16 points |
| Output Type | Sourcing (PNP) Solid-State MOSFET |
| Rated Voltage | 24V DC (Operational Range: 10 – 31.2V DC) |
| Current Rating | 0.5 A per point (8 A total module maximum) |
| Protection | Electronic (Non-Fuse) per point; Short-Circuit & Overload |
| Response Time | On Delay ≤ 1 ms, Off Delay ≤ 1 ms |
| Isolation | Channel Group-to-Logic (500V AC) |
| Operating Temperature | -20 °C to +70 °C (Extended Range) |
| Enclosure Rating | IP20 (Requires panel mounting for protection) |
| Special Coating | Yes (Conformal coating for harsh environments) |
| Status Indicators | 16 Green LEDs (One per output channel) |
| Required Base | 1794-TB3, 1794-TB3S, 1794-TB3G, etc. |
| Lifecycle Status | Active / Mature |
Technical Principles and Innovative Values:
The 1794-OB16PXT is part of the XT (eXtreme Tough) series, designed to outperform standard FLEX I/O in reliability and diagnostics.
- Innovation Point 1: Electronic Fault Protection. Unlike traditional fused outputs that require physical replacement after a fault, this module uses electronic current limiting. In the event of a short circuit, the output turns off automatically and resets once the fault is cleared. This eliminates downtime associated with fuse stocking and replacement, a critical advantage in continuous process industries.
- Innovation Point 2: Harsh Environment Durability. The module’s PCB has a conformal coating that protects against moisture, chemical corrosion, and conductive dust (common in coal handling and mining around Shanxi). Combined with its wide temperature tolerance, this allows it to operate reliably in unheated outdoor cabinets or hot industrial plants where standard modules would fail prematurely.
- Innovation Point 3: High-Density Sourcing Design. The module provides 16 sourcing (PNP) outputs in a compact form factor. Sourcing outputs are often preferred in modern systems as they directly interface with 3-wire PNP sensors and many European-made actuators without requiring intermediate relays, simplifying cabinet wiring.
