Difference between modbus and RS485
- Thread starter SoSolid
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RS485 is hardware serial-interface standard that defines the hardware for carrying a message.
Modbus is a messaging protocol that defines the content of that message.
So far, so good: the two do not 'differ' at all. BUT, there is one hardware requirement for Modbus over a SERIAL-line: the message ends when no character has been sent for 3.5(?) character-times.
That requirement is meaningless for Ethernet because a message 'ends' when its packet ends.
Another potential problem is that Modbus defines a CRC for its messages and Ethernet already has a CRC on its packets.
You need to know how your converter works: how it knows when an output-packet starts and when it ends.
Quoted from a google search.
Modbus is a messaging protocol that defines the content of that message.
So far, so good: the two do not 'differ' at all. BUT, there is one hardware requirement for Modbus over a SERIAL-line: the message ends when no character has been sent for 3.5(?) character-times.
That requirement is meaningless for Ethernet because a message 'ends' when its packet ends.
Another potential problem is that Modbus defines a CRC for its messages and Ethernet already has a CRC on its packets.
You need to know how your converter works: how it knows when an output-packet starts and when it ends.
Quoted from a google search.
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I deal with these 2 quite a bit as I'm an Industrial Control Systems Engineer.
The above post pretty much describes it. If there is something specific you wanted to know I will do my best to help
The above post pretty much describes it. If there is something specific you wanted to know I will do my best to help
I deal with these 2 quite a bit as I'm an Industrial Control Systems Engineer.
The above post pretty much describes it. If there is something specific you wanted to know I will do my best to help
Hey thanks, sorry for the slow response! I don't really understand the difference between the RS485 and MODBUS by understanding is that an RS485 port can be used for MODBUS.