ABB Pluto S20 v2 Cfs Safety PLC

The ABB Pluto S20 v2 Cfs (part number 2TLA020070R4700) is a programmable safety controller designed for industrial machinery safety applications. It offers 12 safety inputs, 8 safety outputs, and 2 test outputs. The unit is certified to SIL3 (IEC 61508) and Performance Level e (ISO 13849-1). The Pluto S20 v2 is configured using ABB’s Pluto Manager software, providing flexible logic design without writing code. It is suitable for emergency stop monitoring, light curtain evaluation, safety gate interlocks, and two-hand controls.

Technical Specifications

Power supply: 24 V DC (19.2-28.8 V). Current consumption: 200 mA typical. Safety inputs: 12 channels, Type 3 according to IEC 61131-2, 24 V DC, sinking/sourcing configurable. Safety outputs: 8 channels (solid-state PNP, 0.5 A per channel). Test outputs: 2 channels (PNP, 100 mA) for cross-circuit detection. Response time: < 20 ms (typical). Safety integrity: SIL3 (IEC 61508), PL e (ISO 13849-1), Cat. 4. Communication: Ethernet (Modbus TCP) for diagnostics and configuration, and one serial port (RS-232) for programming. Operating temperature: -10°C to 55°C. Protection rating: IP20. Dimensions: 110 mm × 45 mm × 77 mm. Weight approx. 0.2 kg. DIN rail mounting (35 mm). The controller includes a removable screw terminal block for all I/O and power connections.

Key Features

• 12 safety inputs (24 V DC) – configurable as single or dual-channel

• 8 safety outputs (PNP, 0.5 A each) – suitable for controlling contactors, valves

• 2 test outputs for OSSD pulsing and cross-circuit detection

• SIL3 / PL e / Cat. 4 certified

• Integrated Ethernet port for Modbus TCP and web server diagnostics

• Pluto Manager software for graphical logic configuration

• Fast response time (<20 ms)

• Integrated memory for 20 safety functions

• Password protection for configuration

• Diagnostic LEDs for every I/O point

Programming and Configuration

The Pluto S20 v2 is programmed using Pluto Manager software (free download from ABB). The user creates safety logic by dragging and dropping pre-defined function blocks such as emergency stop, two-hand control, light curtain, and gate monitor onto a work area and connecting them. No coding is required. The software checks for consistency and generates a safety program that is downloaded via RS-232 or Ethernet. The controller stores the program in non-volatile flash memory. The software also allows simulation and online monitoring of I/O and logic status. Configuration is protected with a password to prevent unauthorized changes.

Safety Functions

The Pluto S20 v2 can implement a wide range of safety functions, including:

• Emergency stop monitoring (Category 1 or 0 stops)

• Safety gate interlocking with guard locking

• Light curtain and safety mat monitoring

• Two-hand control (Type III)

• Enable switch monitoring

• Speed monitoring (with external encoders) – limited support

• Muting function for light curtains

The controller supports both automatic and monitored manual reset. The test outputs can be connected to OSSD inputs of light curtains for pulse testing or to drive cross-circuit detection for dual-channel safety switches.

Communication and Diagnostics

The built-in Ethernet port provides Modbus TCP slave functionality, allowing a PLC or HMI to read the status of the safety controller (e.g., which emergency stop is activated, gate open/closed). The controller also hosts a web server that displays I/O status, fault history, and hardware information. The RS-232 port is used for programming but can also be used to output diagnostic messages to a serial printer or terminal. The front panel LEDs indicate power, run, fault, and the status of each input and output.

Installation and Wiring

Mount the Pluto S20 v2 on a 35 mm DIN rail. Connect 24 V DC power to the +24V and 0V terminals. Wire safety inputs (I1 to I12) to the safety devices (e.g., emergency stop contacts). For dual-channel devices, use two adjacent inputs (e.g., I1 and I2). Connect test outputs (T1, T2) to the device test inputs if required. Safety outputs (O1 to O8) connect to contactor coils, with an external supply (24 V DC) for each output group. Use a separate 24 V supply for output loads to ensure the PLC logic remains active during a fault. All safety wiring must be in accordance with local regulations and ISO 13849-1. Shielded cables are recommended for long runs.

Environmental and Compliance

The Pluto S20 v2 Cfs is CE, UL, and TÜV certified. It meets RoHS requirements. Operating humidity: 10-95% non-condensing. Storage temperature: -40°C to 70°C. Vibration resistance: 2g (10-55 Hz). The controller is suitable for pollution degree 2 environments (control cabinets).

Applications

Typical applications include machine tools (presses, saws), packaging machinery, robotics cells, conveyor systems, and automated assembly lines. The 12 inputs and 8 outputs cover most safety requirements for medium-sized machines. The programmable nature allows the same hardware to serve different machines with different safety logic, reducing spare part inventory.

Conclusion

The ABB Pluto S20 v2 Cfs safety PLC provides a flexible, certified solution for machine safety. Its 12 inputs, 8 outputs, intuitive software, and SIL3/PL e rating make it suitable for a wide range of industrial safety applications.