A Compact Industrial Raspberry Pi with Dual SD Card Support

Strato Pi CM Duo is a high-performance, space-saving industrial server built on the Raspberry Pi Compute Module. Designed for demanding environments, it delivers exceptional reliability and continuous operation—ideal for both industrial and professional applications.

This unit is engineered to meet strict compliance and safety standards:

• Fully compliant with CE directives for low voltage and electromagnetic compatibility (EMC)
• Meets harmonised standards for electrical safety, emissions, and the RoHS directive on hazardous substances
• Also complies with applicable FCC regulations and IC standards for North America

With its dual microSD card architecture and robust design, Strato Pi CM Duo offers a powerful and flexible solution for embedded control systems, automation, and edge computing applications.

Mounting and Enclosure

Designed for compact industrial setups, the device is housed in a 2-module DIN-rail mountable case, with power and serial connections accessible via pluggable terminal blocks for fast installation and maintenance.

Power Supply

Engineered for reliable performance in industrial environments:

• Accepts 9–28V DC input
• Includes surge and reverse polarity protection
• 1.1A resettable fuse
• Supplies up to 1.9A continuous (3A peak) to the Compute Module’s 5V input at 24V DC

Connectivity

Equipped with essential industrial interfaces:

• RS-485 serial port, opto-isolated and ESD-protected, directly connected to the Raspberry Pi
• 2 × USB 2.0 type-A ports with individual power control and fault detection
• 1 × 10/100 Ethernet port

Security and Reliability

Designed for critical applications where uptime matters:

• Dual microSD card system with switchable architecture for redundancy and upgrades
• Independent hardware watchdog controlled via GPIO, with SD card switching support
• Real-time clock (RTC) with replaceable backup battery
• Microchip ATECC608A secure element for cryptographic functions
• Integrated bootloader for updating the onboard microcontroller directly from the Raspberry Pi

Additional Features

• GPIO-controlled status LED
• Activity LEDs for power and serial communication
• Recessed front-panel push-button, connected to a GPIO pin for custom control functions

Dual SD Card Architecture

Long-term reliability, data integrity, and the ability to perform remote system upgrades are critical for industrial and embedded systems. Strato Pi CM Duo addresses these needs with a flexible dual microSD setup.

• The Raspberry Pi Compute Module Lite includes two buses: one for the primary boot SD card, and one for a secondary card.
• Strato Pi CM Duo routes its two SD card slots to these buses via a high-speed switching matrix, controlled by an independent microcontroller.
• This setup allows:
  • Separation of OS and data
  • System redundancy
  • In-field full system upgrades
• The boot card can be switched automatically based on:
  • A scheduled power cycle
  • A defined number of watchdog-triggered resets

Even when using Compute Modules with embedded eMMC storage (where only the secondary SD bus is available), the two microSD slots can still be utilized for failover or additional storage, with switching possible at runtime.

Hardware Watchdog

Unattended systems must recover autonomously from software crashes. Strato Pi CM Duo features a robust hardware watchdog circuit implemented via its onboard microcontroller.

• Independent from the Raspberry Pi’s internal watchdog
• Triggered via GPIO control for simple integration
• Capable of resetting the system upon a software lock-up
• Optionally, the watchdog can switch boot SD cards when triggered, enabling failover and system recovery

This feature ensures operational continuity in critical applications, even in remote or harsh environments.

Power-Controlled USB Ports

USB peripherals such as modems and external drives can occasionally malfunction or draw excessive current, causing instability. Strato Pi CM Duo prevents these issues with power-managed USB ports.

• Each of the two USB 2.0 ports is controlled by a MIC2076 MOSFET switch:
  • Internally current-limited
  • Thermal shutdown protection
  • Fault status flag for overcurrent or thermal events
• The enable and fault signals are routed to the Raspberry Pi GPIO, allowing:
  • Dynamic power control
  • Monitoring and automation from the user application

This enhances the overall reliability of connected peripherals and the system itself.