Selection of Hirschmann cSCALE S6/C8 Mobile Safety Controller

Hirschmann cSCALE S6/C8 Mobile Machinery Safety Controller Selection and Safety Architecture Analysis

Introduction: Challenges in Safety and Flexibility of Mobile Machinery Control

In off-road vehicles, construction machinery, agricultural equipment, and material handling equipment, control systems face extreme environments such as vibration, impact, wide temperature, dust, and spray, while also complying with strict safety regulations such as the Machinery Directive 2006/42/EC and EN ISO 13849, IEC 62061. Traditional PLCs often struggle to balance high-performance computing and functional safety certification, while WIKA Mobile Control's cSCALE series controllers (including models S6, C8, I2, etc.) provide a complete solution that balances performance and safety with a 1GHz high-performance CPU, integrated safety CPU, modular I/O, and IP66/67 protection level. This article is based on the official product manual and systematically outlines the product line division, safety architecture (PL d/SIL 2), I/O modular configuration, communication interfaces, and programming ecology of the cSCALE series, helping engineers to accurately select and quickly deploy in mobile machinery control projects.

Chapter 1 Product Family and Core Positioning

1.1 The three major platforms cover different application scales

The cSCALE series provides a complete product line for mobile automation needs, ranging from compact integration to high-performance expansion:

CSCALE I2: Integrating 4.3-inch graphical HMI with PLC control, suitable for small applications (such as simple agricultural machinery control consoles), using CoDeSys 3.5 programming, HMI and logic control run in the same device, and data exchange does not require network communication. Can run independently or expand distributed I/O (cSCALE DIO) through CANopen. Protection level IP66, working temperature -30 ° C~+70 ° C (optional -40 ° C).

CSCALE S6: Core series, divided into two types of housings: IP20 (cabinet installation) and IP66/67 (direct outdoor installation). Provide 28-168 I/O points, equipped with 2 Ethernet channels USB、 1-3 CAN channels (supporting CANopen, CANopen Safety, J1939). The TrueSafety version integrates a secure CPU and has obtained TUV certified PL d Cat.2/SIL 2 level (compliant with EN ISO 13849 and IEC 62061). High performance application CPU with a clock speed of 500MHz~1GHz, equipped with hardware floating point unit (FPU), built-in 2MB battery buffer RAM and FRAM (no battery required).

CSCALE C8: 1 GHz single core CPU, 2GB Flash, 128MB RAM, supports CoDeSys 3.5 or C/C++programming, also has PL d/SIL 2 certification, suitable for the most complex control tasks.

1.2 Key Common Characteristics

Environmental adaptability: -40 ° C~+70 ° C wide temperature range, shock and vibration resistance, EMC higher than standard requirements.

Programming uniformity: The entire series supports CoDeSys (IEC 61131-3) or C/C++, and the same application software can run on different CPUs.

Redundant architecture: Supports redundant system architecture (primary/backup switching) to enhance availability.

Storage: 2GB Flash is used for program and file storage, and FRAM ensures that critical data is non-volatile.

Chapter 2 Security Architecture and PL d/SIL 2 Certification

2.1 Safety standards and performance levels

Mobile machinery must comply with the Machinery Directive 2006/42/EC and determine the required performance level (PL) through risk assessment. EN ISO 13849 divides PL into five levels, a to e, and most mobile applications require PL d (corresponding to SIL 2 of IEC 62061). The trueSafety versions of cSCALE S6 and C8 have been certified by TUV and meet PL d Cat.2/SIL 2 requirements.

2.2 Dual CPU architecture

The cSCALE S6 safety controller adopts a dual core architecture of functional CPU and safety CPU:

Functional CPU: Run the main application program (IEC 61131 or C/C++), handle complex algorithms, communication, and logic.

Security CPU: Independently monitors security related functions, executes security tasks (such as emergency stop and security shutdown), and runs independently and non destructively with functional CPUs.

Both hardware and firmware have been fully certified to ensure that security features are not affected by non security features. Each I/O module (including digital, analog, PWM output, etc.) is equipped with an independent processor and watchdog. Once a fault (short circuit, overload, disconnection, etc.) is detected, the module immediately cuts off the output on its own without affecting other modules.

2.3 Self diagnostic capability of safety I/O

The safety related I/O has the following self diagnostic functions (compliant with PL Cat. 2 requirements):

Short to battery detection

Short to ground detection

Open load detection

These diagnostic information are fed back to the system integrator in real-time, facilitating quick fault location and reducing downtime. All digital outputs adopt the new generation of high-voltage PROFET technology, integrating short-circuit protection, TVS (transient voltage suppression), and overheat protection.

2.4 Redundant safety cut-off relay