Monday, 28 October 2013

Industrial Arduino

This is one of my tries to make something like an industrial Arduino. Despite most Arduino entusiasts, the Arduino board is not suitable for industrial applications and there are several arguments for it:
  • Industrial controls need electrical isolation between control electronics and power supplies. There are several reasons for it like avoiding leakage currents or just to protect control circuits.
  • Industrial controls are 230Vac or 24Vdc based systems, instead of 5Vdc or 3,3Vdc.
  • It is important to be particularly careful with EMC. Solenoids, motors and others may introduce electrical noise to circuits.
  • Communication buses are still RS232 or RS485. There are other options like CAN-bus or Ethernet-based buses (EtherCAT, ProfiNet or PowerLink).
  • Analog signals use to be 0..10V or 4..20mA rather than 0..5V, but this could be an interesting option.
Arduino can be an interesting option in order to develop sensors or actuators. Another interesting field could be XBEE or other popular communication interfaces, which could be quite expensive when using PLC-based systems.

So this is my prototype:

Its main features are:

  1. Isolated power supply fed at 24Vdc able to supply 3W.
  2. 2 analog inputs that could be set up as 0..5V, 0..10V, 0..20mA or 4..20mA.
  3. 1 PWM analog output 0..5V
  4. Serial port with RS232 and RS485.
  5. Serial EEPROM memory for data back-up.
  6. Expandable system with SPI and I2C buses.
The expansion shown is a 8 PNP digital inputs plus 8 PNP high current digital outputs. These I/O are optoisolated and include led bars for easy diagnostics.

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