Description
Product Overview
The Allen‑Bradley 1797‑PS2N2 is an explosion-proof, intrinsically safe (IS) quad-channel power supply for the Rockwell FLEX Ex remote I/O system. It accepts 24 VDC control power input and delivers four independent energy-limited IS outputs to power FLEX Ex I/O modules located in Class I Div 1 hazardous areas. The unit isolates non-safe side control power and restricts voltage, current and stored energy to safe levels, preventing ignition of flammable gas or vapor. This model was officially discontinued on December 31, 2017.
Technical Specifications
| Item | Parameter |
|---|---|
| Part Number | 1797‑PS2N2 |
| Manufacturer | Allen‑Bradley (Rockwell Automation) |
| Product Family | FLEX Ex Intrinsically Safe I/O |
| Type | Quad IS power supply, explosion-proof enclosure |
| Input Voltage | 19–32 VDC, nominal 24 VDC |
| Input Current | 3.1 A max |
| Output | 4 independent IS channels, 8.5 W per channel, total 34 W |
| IS Output Limits | Uo <9.5 V, Io <1 A, Co <500 nF, Lo <8 µH |
| Conduit Entry | 1 in NPT threaded port |
| Hazardous Certification | Class I Div 1 Groups A,B,C,D; Class II Div1 E,F,G; T4 |
| Operating Temp | -20 °C ~ +60 °C |
| Enclosure | Cast metal explosion-proof housing |
| Mounting | Wall mount for hazardous-area interface cabinet |
| Lifecycle Status | Discontinued (End of Sale: 31-Dec-2017) |
Key Features
- Four fully independent, galvanically isolated intrinsically safe output channels
- Dual redundant 24 VDC input terminals for redundant control power feeding
- Energy limiting circuit on each channel to meet IEC / UL intrinsic safety requirements
- Explosion-proof cast enclosure for installation at hazardous area boundary
- Powers FLEX Ex analog / digital I/O modules in Zone 1 / Div 1 classified locations
- Built-in channel fault monitoring and power status indication
- IS outputs prevent spark or thermal ignition even under wiring short-circuit conditions
- Designed to pair with 1797 FLEX Ex I/O adapters and remote field modules
Application
Deployed in refineries, chemical plants, oil & gas facilities and petrochemical SIS control systems. It serves as the IS power source for FLEX Ex remote I/O racks installed in flammable hazardous zones, supplying power to transmitters, solenoids and discrete field sensors while maintaining explosion protection compliance.
Installation & Maintenance Notes
- ESD precautions required while servicing internal wiring
- Follow explosion-proof wiring and seal requirements for 1-inch NPT conduit
- Verify maximum allowable cable capacitance and inductance per each IS channel during design
- Separate IS field wiring from non-IS control cables; do not mix cable trays
- Confirm redundant 24VDC input supply and polarity before energizing
- Perform intrinsic safety loop calculation for every connected field instrument
- Unit is obsolete; spare replacement requires engineering review and system revalidation
FAQ
Q: What is the difference between 1797‑PS2N2 and 1797‑PS1N? A: 1797‑PS2N2 uses 24VDC DC input; 1797‑PS1N accepts 85–253 VAC mains input. Both provide quad IS outputs for FLEX Ex.
Q: Can it be used for Zone 0? A: No, rated for Class I Div1 / Zone 1 only, not Zone 0.
Q: Is 1797‑PS2N2 still available new from Rockwell? A: No, end of sale Dec 2017. Only surplus / refurbished units available on the aftermarket.
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