Product Introduction

Model Explanation

• 1SAP220500R0001: ABB part number.

• DC551‑CS31:

  • DC = Digital I/O Module

  • 551 = S500 series I/O model code

  • CS31 = CS31 fieldbus slave interface

• 220500: S500 platform code for CS31 bus I/O modules.

• R0001: Hardware revision (initial version).

• Key feature: 8DI + 16DC (configurable DI/DO), CS31 bus interface.

Technical Parameters

• Input: 8 × 24 VDC digital inputs (1‑wire)

• Configurable I/O: 16 × 24 VDC, 0.5 A per channel (DI or DO)

• Bus interface: CS31 slave (S500 backplane, expandable to 7 I/O modules)

• Power supply: 24 VDC (backplane), < 1 W consumption

• Protection: IP20

• Operating temperature: −20 °C to +60 °C

• Storage temperature: −40 °C to +70 °C

• Humidity: 0–95 % non‑condensing

• Dimensions (W×H×D): 68 mm × 62 mm × 78 mm

• Weight: ~0.12 kg

• Mounting: DIN rail (TH35‑15)

• Certifications: CE, UL, CSA, RoHS

• Compatibility: AC500 V2/V3, AC500‑eCo, AC500‑S; S500 I/O system.

Interface and Communication

• Backplane: CS31 bus connector for AC500/S500 I/O bus (plug‑and‑play)

• Field wiring: Screw terminals for 24 VDC sensors/actuators

• Fieldbus: CS31 protocol (slave) for communication with master PLC

• Expansion: Up to 7 additional S500 I/O modules via backplane

• Hot swap: Yes, module can be replaced without system shutdown

• LED indicators: Power, CS31 bus status, input/output channel status.

Core Functions

• Digital I/O: 8‑channel 24 VDC input for sensors; 16‑channel configurable 0.5 A output for relays, contactors, valves

• CS31 communication: Connects AC500 PLC to CS31 fieldbus networks as a slave

• Signal conditioning: Isolation and surge protection for field signals

• Distributed control: Extends AC500 I/O capacity remotely via CS31 bus

• Compact integration: Combines I/O and CS31 bus interface in one module.

Application Scenarios

• ABB AC500 PLC systems requiring CS31 bus connection + 8DI/16DC I/O

• Factory automation: Conveyors, packaging machines, material handling

• Process automation: Pump/valve control, flow/pressure monitoring

• Machine building: CNC machines, robotic cells, assembly lines

• Retrofit projects: Upgrading legacy CS31 systems to AC500/S500.

Usage and Maintenance

• Mount on DIN rail; ensure free airflow, avoid dust/condensation

• Connect 24 VDC backplane power with correct polarity

• Plug module into S500 backplane; secure with locking mechanism

• Wire field devices to screw terminals (0.6 Nm torque)

• Configure CS31 communication via AC500 programming software

• Check LED status: PWR (on), BUS (green = ok), IN/OUT (per channel)

• Periodically tighten terminals, clean dust, inspect for corrosion

• Troubleshoot: Verify power, bus connection, and module LEDs first; replace module if faulty.