Digital-Input Micro PLC Card Reference Design Board

Industry 4.01 marks the fourth industrial revolution, characterized by distributed, intelligent control systems. Breaking from a past with large, centralized programmable-logic controllers, Industry 4.0 allows for highly configurable, highly modular factories, which accept an ever increasing number of sensor inputs while operating at a higher output than ever before. The ultra-small PLC, or Micro PLC, lies at the heart of the Industry 4.0 factory, providing high performance with ultra-low power consumption, in an ultra-small package. The MAXREFDES64 is Maxim’s Micro PLC, octal-channel, digital input card. The MAXREFDES64 reference design features 8-channel digital inputs with isolated power and data. The design integrates a 600VRMS data isolator (MAX14850); a STM32F1 microcontroller; a FTDI USB-UART bridge; a high-efficiency DC-DC converter (MAX17515); and isolated/regulated +24V and +5V power rails (MAX17498C). The entire system typically operates at less than 140mW and fits into a space roughly the size of a credit card. A block diagram of the system is shown in Figure 1.

• Isolated power and data
• Micro PLC form factor
• Device drivers
• Example C source code