The Gould Modicon AS-P810-000 (P810) is a robust, rack-mounted power supply module designed for the classic Modicon 800-series programmable logic controller (PLC) systems. It serves as the backbone for the I/O chassis, converting high-voltage AC line power into the regulated low-voltage DC levels required by the processor and input/output modules. Its reliable, industrial-grade design makes it a foundational component for legacy automation systems that prioritize uptime and stable power distribution.

 

⚙️ Technical Specifications

🔹 Model: AS-P810-000 (P810)

🔹 Input Voltage: Typically 115V/230V AC (Selectable or auto-sensing)

🔹 Output Capacity: Designed to support a full chassis load of 800-series I/O modules

🔹 Mounting: Standard Modicon 800-series I/O rack/chassis slot

🔹 Weight: Approximately 1.5 kg

🔹 Cooling: Passive convection (ensure adequate clearance above/below)

🔹 Status Indicators: LED diagnostics for DC voltage presence and power health

 

🌐 Power Configuration & Wiring

Proper power configuration is essential for system stability:

1. Voltage Selection: Verify the input voltage switch (if applicable to your specific hardware revision) matches the local facility power (115V or 230V AC) before applying power.
2. Grounding: Always connect the chassis ground terminal to a verified earth ground. Failure to do so can lead to electrical noise, causing intermittent communication errors in the PLC backplane.
3. Input Connections: Use properly rated terminal lugs for the AC input to ensure a high-current path with minimal resistance.

 

⚡ Power-Up & Debugging Workflow

1. Pre-Check: Ensure all modules in the rack are fully seated. An improperly seated I/O card can cause a short circuit on the backplane, potentially causing the P810 to trigger its internal protective shutdown.
2. Initial Power-Up: Apply AC power. The “DC OK” or equivalent indicator on the faceplate should illuminate. If it does not, verify the AC input source voltage at the terminal block.
3. Backplane Loading: If the module powers on but drops out under load, monitor the DC output rails with a multimeter. A significant voltage dip during I/O module initialization often points to an aging supply capacitor or an overloaded power circuit.
4. Fault Clearing: If the supply enters a “Shutdown” state due to an overcurrent condition, remove power, identify the problematic I/O module in the rack, and then re-apply power.

 

✅ First-Time Operation Checklist

• Check the physical condition of the power supply for any signs of leaking capacitors or burnt odors.
• Confirm that the input AC fuse is intact and of the correct amperage rating.
• Verify that the terminal block screws are torqued properly to prevent arcing.
• Ensure the cooling vents on the top and bottom of the module are free from dust and debris.
• Measure the output voltage at the backplane test points to ensure it is within the system’s acceptable tolerance (typically \pm 5\%).

 

❓ Common Questions & Answers

Q: Can I replace the P810 while the PLC is running?

A: No. The Modicon 800-series architecture does not support “hot-swapping.” Power must be completely removed from the rack before inserting or removing the power supply.

Q: My power supply is humming/buzzing. Is this normal?

A: A slight audible hum can be common in older magnetic-transformer-based supplies. However, a loud or changing pitch can indicate loose laminations or an internal component under extreme stress. Monitor closely.

Q: Why does the power supply shut down immediately upon turning on?

A: This usually indicates an output short-circuit somewhere in the I/O backplane or a failure in one of the plugged-in I/O modules. Try powering the supply without any I/O cards in the rack to isolate the issue.

Q: Where can I get parts for this vintage power supply?

A: Because this hardware is legacy, components are often found through specialized industrial remanufacturers or surplus dealers. Ensure any replacement units are tested under load.