Description
Application Scenarios
A water and wastewater utility was modernizing a remote pump station that used an RX3i CPU rack in the main control building while a second I/O rack sat 400 m away in a field enclosure. The original single-rack design had no local power at the remote drop, and voltage drop across long cabling was beginning to cause intermittent I/O faults during motor starting. The solution was to install a dedicated IC694PWR321B in the remote baseplate, fed from the local 120/240 VAC service. The pain point was clear: powering remote I/O only from the CPU rack meant long, oversized cables and vulnerability to ground-potential differences and voltage sag. With its own IC694PWR321B, the remote rack received clean, regulated 5 VDC backplane power and a local isolated 24 VDC source for field devices, while the 1500 VAC input-to-backplane isolation helped manage ground-reference differences between the two enclosures. After commissioning, the station reported stable I/O behavior during motor startups and simpler fault diagnosis — a power issue at one rack no longer propagated to the other.
Parameter
| Main Parameters | Value/Description |
|---|---|
| Product Model | IC694PWR321B |
| Manufacturer | GE Fanuc / Emerson (PACSystems RX3i) |
| Product Category | Standard expansion / remote base power supply module |
| Nominal Input | 120/240 VAC, 50/60 Hz or 125 VDC |
| Input Voltage Range | 85–264 VAC or 100–300 VDC (wide universal range) |
| Input Power | 90 VA maximum at full AC load; 50 W at DC input |
| Inrush Current | 4 A peak typical, 250 ms maximum |
| Total Output Power | 30 W maximum (combined across all outputs) |
| 5 VDC Output | 5.0–5.2 VDC nominal; 15 W maximum |
| Relay 24 VDC Output | 24–28 VDC; 15 W maximum |
| Isolated 24 VDC Output | 21.5–28 VDC; 20 W maximum |
| Isolation | 1500 VAC (input to backplane, 1 minute) |
| Ride-Through Time | 20 ms minimum at full load |
| Backplane Support | RX3i serial expansion / remote bases only |
| Mounting | Dedicated power-supply slot in RX3i baseplate |
| Operating Temperature | 0 °C to 60 °C |
| Protection | Overvoltage, overcurrent, short-circuit; internal 2 A input fuse |
| Dimensions / Weight | Single-slot module; channel sources list approx. 135 × 69 × 135 mm and 0.5–1.0 kg — confirm against unit nameplate |
Note: Public sources disagree on exact dimensions and weight for this legacy module; the values above reflect commonly quoted channel-supplied figures. Always verify against the unit nameplate and the current PACSystems RX3i system manual before cabinet design.
Technical Principles and Innovative Values
- Innovation Point 1 — Three useful outputs in one module. The IC694PWR321B is not a single-rail supply. It delivers regulated 5 VDC for the backplane and logic, a separate 24 VDC rail for relay coils, and an isolated 24 VDC output for field or sensor wiring — keeping control power and field power cleanly separated without an external DC supply.
- Innovation Point 2 — Wide universal input for global sites. With an 85–264 VAC / 100–300 VDC input range, one IC694PWR321B part number covers 120 V and 240 V AC mains worldwide as well as 125 VDC supplies, eliminating the need for separate 120 V and 240 V versions or manual voltage selection.
- Innovation Point 3 — 20 ms ride-through protects against nuisance resets. The internal hold-up capacitance keeps outputs valid for at least 20 ms at full 30 W load during a momentary input interruption. In a plant where a contactor closing or a brief brownout can otherwise reset a processor, that margin prevents avoidable restarts and production interruptions.
- Innovation Point 4 — Galvanic isolation for noisy, distributed installations. The 1500 VAC isolation between input and backplane helps the IC694PWR321B maintain stable logic power in environments with noisy motor loads, long cable runs, or differing ground references between enclosures.
- Innovation Point 5 — Self-protecting output stage. Built-in overvoltage, overcurrent, and short-circuit protection, plus an internal 2 A input fuse, means a field-wiring fault is contained locally. The module limits output rather than allowing a fault to cascade into the backplane or connected modules.
