circuit for RS-485 connection with microcontroller

[sharadbags]

rs485 connection

Hi
I need to connect an energy meter to a microcontroller.
The meter uses modbus protocol to transfer data.
How can I read it in PIC18F87J10.

 

[tectona]

rs485 microcontroller

If u want to read/write data from any modbus device than first u should understand how modbus protocol works?
Develop modbus master, so u can send query to device & read/write specific data what u want from that device.

for modbus site just go through below site.
https://www.modbus.org/



Tectona

 

[joby16]

microcontroller rs485

Hi,

Use a MAX485 to interface your microcontroller to the modbus. your application is not clear. if there are only one energy meter has to be connected to the controller then you need not implement the complete modbus protocol. Modbus is mainly used to communicate in a multi master/ slave network

 

[eziggurat]

rs 485 microcontroller

Can I use the ModBus for a single master and multiple slaves? I am going to use to stream data to several slaves on the RS485. For most of our RS485 hardware, we use the MAX3483 device.

 

[joby16]

rs485 connect 8051

modbus can work as single master multi- slave network. If you want to send the same data to all the slaves from the master, then you can use the broadcast mode in the modbus protocol.

 

[eziggurat]

when to use rs-485 connection

I decided not to use the modbus protocol due to the overhead. I going to use a simple protocol where the slave with the correct ID shall respond with acknowledgement. I will also include a broadcast message.