ADF Web HD67561, User Manual, Page: 18 / 23

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User Manual PROFIBUS Slave / Modbus Master
Document code: MN67561_ENG Revision 1.100 Page 17 of 22
ASYNC MODBUS REQUEST:
With the Async Modbus Request is possible to send an Asynchronous Modbus Request form the PROFIBUS to the Modbus network.
To use this feature there are 8 bytes in write where the master PROFIBUS can send the parameters of the request and 4 bytes in read where
the result of the Modbus communication is saved.
The parameter in write are:
BYTE NAME DESCRIPTION
1 Control_TX It is the Control byte used to send the request
2 Spare Not used/ Reserved
3 ID_Device The ID of the Modbus Slave where to send the request
4 Function_Code The Function Code of the request
5, 6 Address Address of the Status/Register to read/write
7, 8 W_Value Value to write (only if it is a Write request)
The Status in Read are:
BYTE NAME DESCRIPTION
1 Control_RX It is the Control Byte used to send the status of the request modbus
2 Status_Request It is the result of the Modbus request
3, 4 R_Value Read value (only if it is a Read request)
The permits values for the “Function Code” are:
•
1 Read one Coil Status
•
2 Read one Input Status
•
3 Read one Holding Register
•
4 Read one Input Register
•
5 Write one Coil Status
•
6 Write one Holding Register
•
15 Write one Coil Status
•
16 Write one Holding Register