Small machines and standalone equipment often need a controller that is compact, easy to wire, and able to run directly from a mains supply without an extra DC power supply. The ABB PM554-RP-AC (order number 1SAP120800R0001) is built for exactly that role: a compact AC500-eCo processor module with onboard digital I/O, relay outputs, and a wide-range 100–240 V AC supply. This guide covers its real specifications, onboard wiring, communication options, and typical applications so maintenance and procurement teams can specify it with confidence. SHLY-PLC supplies these modules as an independent industrial-automation distributor; every unit is inspected and checked before dispatch.
What Is the PM554-RP-AC?
The PM554-RP-AC is the AC-powered, relay-output CPU in ABB's AC500-eCo family, a cost-effective range designed for simple and mid-size automation tasks. Rather than requiring a separate 24 V DC supply, it accepts a direct mains connection, which reduces panel components in small enclosures. The "-RP" designation indicates relay outputs and the "-AC" suffix indicates the wide-range AC supply. The controller is programmed with the same engineering environment used across the AC500 platform, so a program can move between eCo and larger AC500 systems as an application grows.
Key Specifications
| Parameter | Specification |
|---|---|
| Order number | 1SAP120800R0001 |
| Product type | PM554-RP-AC processor module, AC500-eCo |
| Program memory | 128 kB Flash EPROM |
| Processor | Freescale ARM, 32-bit, 50 MHz clock |
| Onboard digital inputs | 8 digital inputs |
| Onboard outputs | 6 relay outputs |
| Supply voltage | 100–240 V AC wide range (-15%/+10%), 50/60 Hz |
| Current consumption (max.) | 200 mA at 100 V AC; 110 mA at 240 V AC |
| Power dissipation (max.) | 4.8 W |
| Interfaces | I/O bus, COM1 (RS-485), optional COM2 |
| Expandability | Up to 10 I/O modules |
| Degree of protection | IP20 |
| Weight | Approx. 400 g |
Onboard I/O and Wiring
The CPU provides eight digital inputs and six relay outputs on pluggable terminal blocks, which simplifies servicing because a module can be exchanged without unwiring every conductor. The relay outputs can switch small loads directly and provide electrical isolation between the controller logic and the field circuit, making them well suited to driving contactors, solenoids, and indicators. When more points are needed, the system can be expanded with up to ten S500 I/O modules, supporting a much larger total of digital and analog channels over the I/O bus.
Because the module runs from 100–240 V AC, panel designers should still observe the published voltage tolerances and use appropriate fusing on the mains input and on each output circuit. Field wiring, conductor size, and cable temperature rating must match the load to prevent terminal heating.
Communication and Programming
COM1 is an RS-485 serial port with a configurable transmission rate from 1.2 to 187.5 kbit/s. It supports Modbus as both master and slave, serial ASCII communication, and the CS31 protocol as master. An optional second port (COM2) can be added depending on configuration. Note that this particular variant does not include onboard Ethernet; applications that require Modbus TCP or other network connectivity use the Ethernet versions of the AC500-eCo CPUs or an external gateway.
The processor executes roughly 1000 binary instructions in 0.08 ms and 1000 floating-point instructions in about 1.2 ms. A RUN/STOP switch, status LEDs for power, run, error and I/O state, and password protection for the user program are provided. Useful accessories include the MC503 memory card, the TA561-RTC real-time clock, and TA562-RS serial adapters.
Typical Applications
- Standalone machines powered directly from AC mains
- Conveyors, packaging machines, and small process skids
- Compressor, pump, and fan control with relay outputs
- Building-services and utility equipment with simple sequencing
- Retrofit projects where a compact, AC-fed controller reduces panel changes
For these and similar duties, the PM554-RP-AC offers a practical balance of onboard I/O, relay switching, and mains-voltage convenience. You can browse related controllers in our ABB range and the broader PLC collection.
Lifecycle and Spare Parts
ABB classifies the PM554 family under its mature product lifecycle phase, so maintenance teams should secure spares while stock is available rather than waiting for a failure. Mature AC500-eCo modules remain a practical way to keep installed equipment running without a full redesign. When a controller is no longer in current production, our Discontinued Products range and our sourcing team can help locate matching units; simply send the part number and we will confirm availability and compatible alternatives.
Frequently Asked Questions
Does the PM554-RP-AC need a 24 V DC power supply?
No. This variant runs directly from a 100–240 V AC mains supply, so a separate DC supply is not required for the CPU itself. Always follow the published voltage tolerances and fusing guidance.
What is the difference between PM554-RP and PM554-RP-AC?
Both have eight digital inputs and six relay outputs. The PM554-RP is powered from 24 V DC, while the PM554-RP-AC accepts a 100–240 V AC wide-range supply.
Can the controller be expanded with more I/O?
Yes. Up to ten S500 I/O modules can be connected over the I/O bus, allowing a substantial increase in digital and analog channels beyond the onboard points.
Does this CPU include Ethernet?
No, the PM554-RP-AC uses an RS-485 serial port (COM1) supporting Modbus, ASCII, and CS31. Ethernet is available on the dedicated Ethernet AC500-eCo CPU variants.
SHLY-PLC is an independent distributor of industrial automation parts. All brand names, model numbers, and trademarks are the property of their respective holders and are used only for identification and compatibility reference.