The importance of safety control systems in the field of industrial automation is self-evident. It is not only a key defense line to ensure personnel safety, but also an important support to ensure production continuity. The Pluto safety PLC series launched by ABB JOKAB SAFETY has brought revolutionary changes to the design of safety systems with its unique "All Supervisor" concept and innovative dynamic signal technology.
Pluto is not only a Safety Programmable Logic Controller (Safety PLC), but also a new design concept for safety systems. It simplifies the construction process of complex safety systems while achieving the highest safety levels - EN 954-1/EN ISO 13849-1 Category 4, PL e, and IEC/EN 61508 SIL 3. This article will comprehensively analyze the technical connotation and application value of Pluto safety PLC from multiple dimensions such as product concept, core features, hardware series, software tools, network integration, and application cases.
1. The concept of "All Supervisor": redefining the architecture of security systems
1.1 Limitations of Traditional Safety PLCs
Traditional safety PLC systems typically adopt a "master-slave" architecture, where a single supervisor is responsible for coordinating and managing multiple slave stations. In this architecture, communication between slave stations must be carried out through the master controller, which increases the complexity and response time of the system, while also creating the risk of single point of failure.
1.2 Pluto's Innovative Concept
Pluto has disrupted this traditional architecture. In the Pluto system, there is no "master-slave" relationship, and every Pluto unit connected to the same secure bus is a "supervisor" unit. Each Pluto can see the input and output status of other Pluto and make independent decisions based on the local security environment.
This concept brings significant advantages:
Simplified communication: Any Pluto can directly read the input state of other Pluto, as simple as reading its own input
Flexible system expansion: up to 32 Pluto units can be connected, and the system scale can be expanded from 20 I/O points (B20 series) to 390 I/O points (B46 series)
Modular machine design: Each machine module can be equipped with an independent Pluto, and the modules are interconnected through a secure bus to form a complete security system
High availability: Each Pluto makes independent decisions, and a single point of failure will not cause the entire system to crash
2. Dynamic signal technology: achieving maximum safety with minimal input
2.1 Limitations of Traditional Static Signals
The traditional static signal (+24V or 0V) implementation of a two channel safety structure requires two independent input channels. When multiple safety devices need to be connected in series, the number of input points will increase sharply, causing a shortage of controller I/O points.
2.2 Dynamic Signal Principle
Pluto uses innovative dynamic signal technology to achieve the highest level of security for a single channel by sending square wave signals and evaluating them upon return. Its working principle is as follows:
Pluto generates three unique dynamic signals: A pulse, B pulse, or C pulse
When the signal passes through safety devices such as light curtains, emergency stop buttons, and safety switches, the signal is reversed once for each device it passes through
Pluto receives the return signal and compares it with the expected signal
If the signal does not meet expectations (such as short circuit, signal loss, or incorrect signal type), Pluto immediately cuts off the safety output
2.3 Advantages of Dynamic Signals
Extremely high input efficiency: In dynamic signal systems, up to 10 safety sensors can be connected in series to one input channel while maintaining safety levels of Category 4, PL e, and SIL 3. This means that a Pluto B20 (8 safety inputs) can connect up to 80 safety sensors, while a Pluto B46 (24 safety inputs) can connect up to 240 safety sensors.
Comprehensive fault detection: The dynamic signal system can detect various fault situations, including:
Short circuit between sensors
Short circuit between sensor input and output
Short circuits between different dynamic signals
Short circuit to power or ground
2.4 Flexible combination of static and dynamic
Pluto's input can be configured as either a dynamic signal input or a static signal input, meeting the needs of different types of safety devices:
Dynamic input: Eden non-contact sensor, SPOT light curtain, Tina adapter, etc. suitable for ABB JOKAB SAFETY, can achieve the highest single channel safety level
Static input: suitable for traditional mechanical switches, requiring two input channels to achieve the highest safety level

3. Hardware series: meet diverse application needs
Pluto offers multiple models to adapt to various application scenarios ranging from standalone devices to large-scale integrated systems.
3.1 Overview of Basic Models
Model Safety Input Non safety Output/Safety Input Safety Relay Output Safety Transistor Output Safety Bus Special Functions