Description:The 1797-PS1E is an intrinsically safe (IS) power supply module from Allen‑Bradley’s FLEX Ex product family, designed specifically for hazardous locations (Zone 1/22). It converts a wide-range AC input (85–253V) into four independent, galvanically isolated DC outputs, each limited to intrinsically safe levels (<9.5V, <1A). Housed in a robust flameproof (Ex d) and IP65-rated enclosure, its primary function is to safely power FLEX Ex I/O adapters and modules installed in potentially explosive atmospheres, ensuring energy limits are never exceeded even under fault conditions.Application Scenarios:In an offshore oil platform’s classified gas zone, the 1797-PS1E is mounted in a safe area cabinet. It powers a distributed network of 1797 FLEX Ex I/O blocks that connect to pressure transmitters and solenoid valves in the hazardous area. Its four isolated outputs allow separate power segments for different process units, ensuring a single ground fault in one loop does not disrupt the entire control system.
Parameter:
| Main Parameters | Value/Description |
|---|---|
| Product Model | 1797-PS1E (Series B) |
| Manufacturer | Allen‑Bradley (Rockwell Automation) |
| Input Voltage | 85 – 253 V AC (47–63 Hz) |
| Output Channels | 4 (independent, galvanically isolated) |
| Output Power per Channel | 8.5 W (max) |
| IS Output Voltage (Uo) | ≤ 9.5 V DC (limited) |
| IS Output Current (Io) | ≤ 1 A (limited) |
| Total Output Power | 34 W (4 x 8.5 W) |
| Enclosure Rating | IP65, Flameproof (Ex d) |
| Hazardous Area Certification | ATEX / IECEx (Zone 1, Zone 22) |
| Operating Temperature | -20°C to +70°C |
| Input Connection | M20 x 1.5 gland (6–12 mm cable) |
| Output Connection | M16 x 1.5 gland (4–8 mm cable) |
| Weight | ~7.7 kg |
Technical Principles and Innovative Values:The 1797-PS1E is not a standard voltage regulator but a “source of power” for intrinsically safe systems.
- Innovation Point 1: Quadruple Galvanic Isolation: Unlike standard power supplies with a common output bus, the 1797-PS1E provides four fully isolated output channels. This prevents fault propagation between circuits, allowing maintenance on one I/O segment without shutting down the entire hazardous area control system.
- Innovation Point 2: Integrated Energy Limiting: The module incorporates current (Io) and voltage (Uo) limiting circuits that are certified to intrinsically safe standards (IEC 60079-11). This eliminates the need for external Zener barriers or isolators between the power supply and the field devices, simplifying system design and reducing cabinet space.
- Innovation Point 3: Ruggedized Field Construction: With an IP65 and flameproof (Ex d) enclosure, the module can be installed directly in harsh industrial environments without requiring an additional protective cabinet. The use of M20/M16 cable glands ensures a sealed connection, protecting against dust and moisture ingress.
