Description
- Model: PF3S-PSA2
- Brand: IDEC Izumi Corp.
- Series: FA-3S / PF3S Series
- Core Function: System power supply for the FA-3S PLC rack
- Product Type: Rack-Mount Power Supply Module
- Key Specs: 100–240V AC Input 2000mA (2A) Output 85VA Power Consumption
- Input Voltage: 100–120V AC / 200–240V AC (Auto-sensing or jumper selectable)
- Frequency: 50/60 Hz
- Output Current: 2000 mA (Internal system power)
- Power Rating: 85 VA
- Wiring Requirements: Use minimum 60°C copper wire only
- Terminal Torque: 0.8 N·m
- Status Indicators: Power LED (Green)
- Weight: Approx. 2.34 kg (as part of a standard rack configuration)
- Mounting: Plugs into the far-left slot of a PF3S series base rack
IDEC PF3S-PSA2
IDEC PF3S-PSA2
IDEC PF3S-PSA2
Application Scenarios & Pain Points
The PF3S-PSA2 is the literal heartbeat of the IDEC FA-3S PLC system. It converts high-voltage AC utility power into the stabilized DC voltages required for the CPU and I/O modules to communicate across the backplane. Since this is the first point of entry for electrical power, it is the most vulnerable module to power surges, lightning strikes, and brownouts.
A common pain point with aging PF3S systems is intermittent CPU resets. Over time, the internal electrolytic capacitors in the PSA2 can dry out, leading to “dirty” power (voltage ripple). This causes the CPU to fault or reboot randomly, which is often misdiagnosed as a software bug or a faulty CPU module.
Typical Application Scenarios:
- Automotive Assembly Lines Powering the logic for conveyor synchronization and robotic cell interlocking.
- Water Treatment Facilities Reliable 24/7 power for PLC-controlled filtration and pump sequencing.
- Food & Beverage Packaging Ensuring stable control for high-speed labeling and filling machines.
- Legacy System Support Replacing failed power units in systems that have been running for 20+ years without a major overhaul.
Case Study: The “Monday Morning” Failure
Background: A manufacturing plant in Japan found that their main packaging machine failed to start every Monday morning. The PLC’s green “Run” light would flicker and then stay dark.
Problem: We traced the issue to the PF3S-PSA2. After the plant shut down for the weekend, the power supply cooled down. The failing capacitors inside the PSA2 could no longer “start” the circuit while cold. Once the cabinet was warmed up with a heat gun, it would start—a classic sign of power supply end-of-life.
Solution: Replaced the unit with a certified PF3S-PSA2 from our emergency stock.
Result:
- Zero Downtime: Monday morning startups became 100% reliable.
- Cost Savings: Avoided a full system upgrade costing over $10,000.
- Engineer’s Insight: “In the FA-3S series, if you see the ‘Power’ LED flickering, don’t wait for a total failure. Swap the PSA2 immediately to protect your CPU and memory.”
Compatible Replacement Models
The PF3S-PSA2 is the standard AC power supply for this series.
| Original Model | Replacement Model | Compatibility | Note |
|---|---|---|---|
| PF3S-PSA2 | PF3S-PSA2 | ✅ Exact Match | Standard 2000mA AC Supply. |
| PF3S-PSA2 | PF3S-PSD2 | ❌ Incompatible | PSD2 is a DC Input version (24V DC). |
| PF3S-PSA2 | FA3S-PSA1 | ⚠️ Physical | Older FA3S version; check rack dimensions and amperage. |
Troubleshooting Quick Reference
| Symptom | Possible Cause | Relation | Quick Check | Action |
|---|---|---|---|---|
| Power LED is Dark | Main Fuse Blown | ✅ High | Check 100-240V AC at the input terminals. | Replace fuse or PSA2 module. |
| CPU “Power” LED Off | Backplane Fault | ✅ High | Measure 12V/5V DC across the backplane pins. | Replace PSA2 or check for I/O shorts. |
| Intermittent Reboots | Voltage Ripple | ✅ High | Check AC input stability and look for “leaking” capacitors. | Replace PSA2 module. |
| ATTN/Fault LED on CPU | Overload | ⚠️ Med | Calculate total mA draw of all installed modules. | Reduce I/O load or add expansion rack. |
❗ Pro Tip: Terminal Torque
The PF3S-PSA2 requires a specific torque of 0.8 N·m. Loose power connections generate heat, which can melt the plastic housing over time or cause “arc-noise” that crashes the PLC. Always use a torque-limiting screwdriver during installation.
Handling & Installation:
- Safety: High voltage (up to 240V AC) is present on the screw terminals. Always disconnect the main breaker before handling.
- Mounting: The PSA2 module MUST be installed in the leftmost slot of the rack. It provides power via the backplane bus to all other modules to its right.
- Grounding: Ensure the frame ground (FG) terminal is connected to a clean earth ground to reduce electrical noise on the system bus.
