The Standard for Safety-Critical Automation

The HIMA F 8650X is a high-performance central module designed for the HIMA H51q Programmable Electronic System (PES). It serves as the primary processing hub for safety-related applications, including H51q-MS, -HS, and -HRS configurations. Engineering teams worldwide trust this module for its ability to meet the most stringent international safety standards, achieving SIL 3 compliance according to IEC 61508.

In industries where failure is not an option—such as oil and gas, chemical processing, and power generation—the F 8650X provides the deterministic control and fault tolerance required to protect both personnel and assets. This central module manages complex safety logic while maintaining continuous self-diagnostics, ensuring that the system remains in a safe state during any hardware or software anomaly.

Core Processing and Memory Architecture

HIMA built the F 8650X around the proven Intel 386EX 32-bit microprocessor. Operating at a clock frequency of 25 MHz, this processor delivers the stability and predictable execution times necessary for real-time safety functions. The module features a robust memory layout to handle both the operating system and user-defined safety programs:

• Operating System Memory: 1 MB Flash-EPROM.
• User Program Memory: 1 MB Flash-EPROM.
• Data Storage: 1 MB SRAM.

This memory configuration ensures that the safety system retains its logic and data even during power cycles. The use of Flash-EPROM for the operating system and user programs provides non-volatile storage, while the SRAM handles high-speed data processing during active operation.

Technical Specifications Table

The following table summarizes the key technical parameters for the HIMA F 8650X:

Advanced Connectivity and Networking

The F 8650X provides exceptional connectivity through two electrically isolated RS 485 serial interfaces. These ports facilitate secure data exchange with peripheral devices while protecting the central module from electrical surges or ground loops. The pinout includes dedicated lines for Receive/Transmit Data (RxD/TxD) and control signals, ensuring reliable peer-to-peer or bus-based communication.

For facilities requiring modern networking, the F 8650X integrates seamlessly with the F 8627X communication module. This combination allows the central module to connect to Ethernet networks, supporting protocols such as:

• safeethernet: For safety-related communication between HIMA systems.
• Modbus TCP: For integration with standard industrial control and monitoring systems.
• ELOP II TCP: For efficient programming and diagnostic access via a PADT (Programming and Debugging Tool).

Comprehensive Diagnostics and Safety Watchdog

Safety systems require constant visibility into their operational health. The F 8650X features a four-digit alphanumeric matrix display on the front panel. This display provides real-time error codes and system information, which technicians can toggle using two integrated switches.

To ensure the highest level of protection, the module includes a safety-related watchdog. This hardware-based timer monitors the processor’s activity. If the system detects a fault or a logic hang, the watchdog triggers a shutdown via a 24V output (loadable up to 500 mA). This fail-safe mechanism prevents the system from entering an unpredictable state, maintaining the SIL 3 integrity of the entire plant.

Maintenance and Battery Management

HIMA designed the F 8650X for long-term industrial service, but regular maintenance ensures peak performance. The module relies on a Lithium buffer battery (type CR 2477N) to protect the SRAM data during power interruptions.

• Battery Life: 1,000 days at 25°C or 200 days at 60°C.
• Replacement Cycle: HIMA recommends replacing the battery every 6 years while the CPU is in operation to avoid data loss.
• Alert System: If the display shows the “BATI” code, the user must replace the battery within three months.

Important Note: When upgrading an older F 8650 module to the F 8650X version, you must also update the fan concept to ensure proper thermal management within the H51q rack.