The master station checks that the send request bStartDirection (M0) is turned on, and transfers contents of uTransferFrom [0] to [3] (D0 to D3) to the send
data W0 to W3.
When the transfer is completed, the master station turns on Y1000.
The local station checks that X1000 is turned on, and transfers contents of the receive data W1000 to W1003 to uTransferTo [0] to [3] (D0 to D3).
When the transfer is completed, the local station turns on Y1000.
The master station checks that X1000 is turned on, and turns off Y1000.
The local station checks that X1000 is turned off, and turns off the reception complete signal Y1000.