PLC – I2C/SPI Sensor Adapter

My next module is a TOF sensor that detect distance to objects, but those modules are based on I2C and I might need some distance between detector and PLC, so I have 2 options.

  1. I can move a PLC module close to the I2C device
  2. or I can use a separate RS485/CAN Interface.

It sound a bit overkill to create a module that basically convert RS485/CAN to RS485/CAN, but the RS485/CAN on all modules are IPC designed for high speed, short range that don’t need isolation. If I want to communicate with adapters 2-5 meters away I need some isolation, power and slower speeds + I would like to connect to multiple devices. I use RS485 in this example because that allows me to use cheaper MCU’s on the Adapter. CAN is more ideal, but harder to align and require MCU’s with CAN Interface. That said I will create both because I like CAN.

I2C or SPI on the other hand is TTL logic and will not survice mutch cable dispance.b Below is a typical Laser/TOF sensor with I2C.

Categories: PLC

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