Rievtech PR-12 Series, Руководство пользователя и программиста

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MODBUS communication protocol
MODBUS protocol is a common language used in electronic controllers.Different
devices can communicate with each other by using the MODBUS communication protocol.
It has become a general industrial standard.You can use it to connect different
devices.
This protocol defines a message structure, no matter what network they use to
communicate.It describes the process of controller requesting to access other
devices.It has formulated message domain structure and the common format of the
content.
MODBUS network protocol determines that each controller should know its address.
It identifies the messages sent from different addresses and decides what action
to take.The controller generates feedback information, the format of the
information is the information format of MODBUS.It is issued through the MODBUS
protocol.
MODBUS address usually contains data type and offset.MODBUS address contains a
total of 5 characters.The first character represents the data type and the other
four characters represent the correct values in the data type.
MODBUS addressing:
0XXXX are discrete outputs
1XXXX are discrete inputs
3XXXX are analog inputs
4XXXX are hold registers
You can use “ MODBUS address query ” to query the MODBUS address of the variable ，
Steps are as follows:
Menu bar
→
PLC
→
MODBUS address query