In the area of industrial internet of things, there are so many industrial slave devices behind the programable logic controller, they are not given any ip address or identity, how would we to map these devices 's identity and their controls over the application level on the cloud. For example, I am going to use the rasberrypi as a gateway, this gateway is connected with a PLC. Behind the PLC are many connected many slave devices like fans, LED lights, CO2 sensors.
I am very new to PLC and modbus protocol, even after reading the introduction, I still have the questions, the main question is how could we register and map the slave devices to gateway and finally to the IOT application layer. and under the main question there are many small questions to be answered like
- how could I determine the address for each device, is it determined manually or can be discovered from the slave device ?
- if one slave device is disfunctional, how could we find it out?