B&R X20CP1685 X20 System PLC CPU Module

Market-Leading Controller Overview

The X20CP1685 (X20CP1685) serves as a premier industrial processing engine within the modular B&R X20 automation ecosystem. Designed to spearhead high-speed process loops and demanding algorithmic computations, this central processing unit thrives in mission-critical deployments across manufacturing, maritime power plants, and oil refining infrastructure. By incorporating an Intel Atom E3915 microprocessor executing at 800 MHz alongside a dedicated background I/O co-processor, the unit eliminates scanning bottlenecks to preserve deterministic microsecond task cycles. The integration of remanent SRAM and heavy-duty eMMC storage ensures that operational variables and recipe matrices remain intact during sudden grid fluctuations, substantially cutting down-time losses in automated production facilities.

Hardware Architecture and Technical Configuration

The core computing architecture leverages an onboard Floating Point Unit (FPU) to facilitate rapid 64-bit floating-point math, crucial for complex multi-axis motion synchronization. Communication topology is a primary focus of this control module: it features an integrated POWERLINK V2 master interface that operates as a managing node (Type 4) to govern synchronized real-time networks via Poll-Response Chaining. For horizontal plant integration, a separate Gigabit Ethernet port handles high-bandwidth SCADA and ERP data routing independently. Field distribution utilizes the proprietary X2X Link master backplane bus, driving up to 7 W of local I/O module power with full support for parallel or redundant secondary supply configurations. A single modular slot provides expansion capabilities, allowing engineers to append fieldbus interfaces like CANopen, Profibus DP, or DeviceNet without replacing the primary CPU.

Technical Engineering Specifications

Common Operational Queries

Does the module package include the operational system software storage media?

No. While the processor includes 1 GB of onboard eMMC flash, the primary boot system and localized application logic require a matching CompactFlash card. This card must be sized and purchased separately based on your automation runtime data logging requirements.

How does the CPU handle memory corruption from electromagnetic interference or alpha radiation?

The 512 MB LPDDR4 SDRAM structure features full hardware-implemented Error-Correcting Code (ECC) functionality. It automatically detects and fixes single-bit memory errors in real time, preventing data corruption and sudden CPU traps during continuous operation.

What external fusing is mandatory to protect the integrated power distribution paths?

The main CPU logic and X2X Link circuits feature internal, non-replaceable electronic fuses. However, the heavy-duty I/O power supply path, which can draw up to 240 W, requires an external slow-blow line fuse rated at a maximum of 10 A to safeguard the internal terminal contacts against overcurrent faults.

Field Engineering and Safety Directives

• Thermal Management and Derating Layouts: The X20CP1685 uses a fanless convection cooling design. Maintain a minimum clear boundary spacing of 30 mm above and below the module assembly to ensure unhindered airflow. When mounting horizontally, the ambient air temperature must not exceed 60 deg C. For vertical DIN rail layouts, strict derating caps the maximum ambient temperature at 50 deg C. If operating at elevations higher than 2000 m, apply linear temperature derating curves due to reduced air density.

• Battery Maintenance and Clock Calibration: The non-volatile real-time clock (RTC) utilizes an internal lithium cell for data buffering when system power is disconnected. The battery provides an operational lifespan of 4 years under typical load cycles. If the control system remains unpowered at an average ambient temperature of 23 deg C, replace the battery cell every 2 years to prevent loss of remanent variables. Monitor the battery status registers via Automation Studio software or the onboard physical diagnostics LED.

• Shielding and Galvanic Isolation Protocol: While the Ethernet, POWERLINK, and X2X Link circuits maintain internal galvanic isolation, terminate all communication cable shields at the entry point of the control enclosure using low-impedance ground clamps. Wire the functional earth ground terminal directly to the DIN rail mounting plate using a short, heavy-gauge copper strap to prevent high-frequency noise from disrupting the 200 us high-speed task class executions.