ANNEX A - MODBUS OVERVIEW
57
A 1.5 Command Transfer from PLC to FV300
1) The PLC will examine the Command Done bit in the FV300 overall status regis-
ter and wait until it is cleared by the FV300.
2) The PLC will set the Command Code in the Command Register.
3) The PLC will set the Command Request bit in the Command Register.
4) The FV300 will detect the change in Command Request bit and will action the
command code.
5) When completed, the FV300 sets the Command Done in the Overall Status
register.
6) The PLC will detect that the Command Done bit has been set showing that the
command has been completed.
7) The PLC will clear the Command Request bit in the Command Register.
8) The FV300 detects the change in Command Request bit and clears the Command
Done bit.
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