Description
- Model: PM802F
- Part Number: 3BDH000002R1
- Brand: ABB (Distributed Control Systems)
- Series: Freelance / AC 800F
- Core Function: Central Processing Unit (CPU) / Main Controller
- Product Type: Base Controller Module for Freelance 800F System
- Key Specs: 4 MB Battery-buffered RAM, Motorola PowerPC architecture, high-speed fieldbus connectivity.
- Processor: Motorola PowerPC (High-efficiency RISC)
- Memory:
- 4 MB RAM (Data and Application storage)
- 2 MB Flash-EPROM (Firmware)
- Interfaces:
- 1x Serial (Diagnostics/Configuration)
- Integrated slots for up to 4 Fieldbus modules (Profibus DP, Foundation Fieldbus, CAN, or Ethernet)
- Diagnostics: 8-digit alphanumeric front-panel display for system status and error codes.
- Power Supply: 24 V DC (Typically via SA801F/SA811F modules).
- Execution Time: Real-time multitasking OS for sub-millisecond control loops.
- Redundancy: Supports hardware redundancy (Line and CPU redundancy configurations).
PM802F 3BDH000002R1
Application Scenarios & Pain Points
The PM802F is the “compact powerhouse” of the ABB Freelance DCS. It integrates the functions of a traditional PLC with the scaling power of a DCS, making it a favorite for medium-sized process plants. The biggest pain point for maintenance teams is Battery Failure. The 4 MB of RAM is volatile; it depends on a small lithium battery located in the battery compartment. If that battery dies while the rack is powered down (during an outage or maintenance), the entire application program is lost.
1. Chemical and Pharmaceutical Batching
Managing complex recipe logic and PID loops for reactors where deterministic timing is required for product quality.
2. Water and Wastewater Treatment
Controlling distributed pump stations and filtration systems using Profibus or Ethernet communication.
3. Food and Beverage Processing
Handling high-speed packaging lines and pasteurization processes with integrated safety and visualization.
Case Study: The “Monday Morning” Memory Loss
Background: A specialty chemical plant shut down for a scheduled 48-hour maintenance window. When they attempted to restart on Monday morning, the PM802F display showed “NO PROG” (No Program).
The Problem: The internal lithium battery had been exhausted for months, but the “Low Battery” LED on the front panel had been ignored. As long as the rack had 24V power, the program stayed in RAM. Once the power was cut for maintenance, the RAM cleared instantly.
The Solution: We supplied a certified PM802F (3BDH000002R1) with a fresh, date-coded battery. We provided the customer with the procedure for loading their Freelance project from their engineering station (DigiVis/Control Builder F).
The Result: The plant was back online by mid-day.
- Avoided Loss: Prevented several days of downtime searching for backup files and old hardware.
- Takeaway: The PM802F is a “volatile” controller. Always replace the battery every 2-3 years, and never power down the rack if the “BAT” LED is red.
Compatible Replacement Models
| Original Model | Replacement Model | Compatibility | Key Differences | Workload |
| PM802F | PM802F (3BDH000002R1) | ✅ Direct | Industry standard for AC 800F | Plug & Play |
| PM803F | PM802F | ⚠️ Partial | 803F has more RAM (16MB); check project size | Check RAM |
| PM783F | PM802F | ❌ No | Older architecture; different bus | System Upgrade |
Engineer’s Advice: If you are replacing a PM802F, ensure you check your Firmware Version. The PM802F can run various versions of the Freelance OS. If your new module has Version 9.2 but your plant is on Version 7.1, the controller will not join the network. I can help you flash the correct firmware before shipping.
Troubleshooting Quick Reference
| Symptom | Possible Cause | PM802F Related? | Quick Check | Action |
| “BAT” LED Red | Lithium Battery Dead | ✅ High | Check voltage of CR2032/specialty cell | Replace Battery |
| Display: “E01” | Internal HW Fault | ✅ High | Cycle power; check for heat | Replace Module |
| Display: “STOP” | Processor Halted | ✅ High | Check diagnostic buffer in Freelance | Reset/Reload |
| No “Run” LED | Power Supply Fault | ⚠️ Medium | Verify 24V at SA811F module | Check Power Module |
Expert Maintenance Tips:
- Battery Maintenance: ❗ Critical! The battery is located behind a small flap. Always replace it while the controller is powered on to preserve the memory. If you replace it while powered off, you will lose your program.
- Fieldbus Modules: The PM802F uses “plug-in” modules (like the FI830F for Profibus). When swapping a CPU, ensure the pins on these modules are clean and not bent.
- Firmware Matching: Before installing, use the “Freelance Hardware Freelance Tool” to verify the firmware revision matches your engineering station version.
