Slave device, serial communications system, and communication method for serial communications system
AssigneeFanuc Corporation
InventorEijirou Hoshino
Life of this patent
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Abstract
A slave device is equipped with a communications circuit that carries out serial communications in a communication mode in which received data is transmitted in synchronism with its own clock pulse signal, a communications line that carries out serial communications in a pass through mode in which received data is directly transmitted without depending on its own clock pulse signal, a switching unit that switches from the communication mode to the pass through mode, and a control unit that controls the switching unit.
Claims14
A slave device connected in a daisy chain fashion with a master device, and which is equipped with a communications circuit configured to carry out serial communications in a communication mode in which received data is transmitted in synchronism with its own clock pulse signal, the slave device further comprising:
- a communications line configured to carry out serial communications in a pass through mode in which the received data is directly transmitted without depending on its own clock pulse signal;
- a switching unit configured to switch from the communication mode to the pass through mode;
- and
- a control unit configured to control the switching unit,
- wherein, in a case that the received data from the master device is synchronization request data configured to request time synchronization with a slave device other than itself, then after having transmitted in the communication mode the synchronization request data received by the slave device itself, the control unit controls the switching unit to switch from the communication mode to the pass through mode.
A serial communications system equipped with a master device and a plurality of slave devices connected in a daisy chain fashion with the master device, wherein:
- the master device transmits, to a slave device that is connected to a subsequent stage, synchronization request data including request information configured to request time synchronization, and slave device information indicating a slave device for which time synchronization is desired;
- each of the slave devices comprises:
- a communications circuit configured to carry out serial communications in a communication mode in which received data is transmitted in synchronism with its own clock pulse signal;
- a communications line configured to carry out serial communications in a pass through mode in which the received data is directly transmitted without depending on its own clock pulse signal;
- a switching unit configured to switch from the communication mode to the pass through mode;
- and
- a control unit configured to control the switching unit;
- wherein, in a case that the received data from the master device is the synchronization request data, and the slave device information contained within the synchronization request data indicates a slave device other than itself, the control unit, after having transmitted the received synchronization request data in the communication mode, controls the switching unit to switch from the communication mode to the pass through mode.
A communication method for a serial communications system equipped with a master device and a plurality of slave devices connected in a daisy chain fashion with the master device, wherein:
- each of the slave devices comprises:
- a communications circuit configured to carry out serial communications in a communication mode in which received data is transmitted in synchronism with its own clock pulse signal;
- a communications line configured to carry out serial communications in a pass through mode in which the received data is directly transmitted without depending on its own clock pulse signal;
- and
- a switching unit configured to switch from the communication mode to the pass through mode;
- the communication method comprising:
- a synchronization requesting step in which the master device transmits, to a slave device that is connected to a subsequent stage, synchronization request data including request information configured to request time synchronization, and slave device information indicating a slave device for which time synchronization is desired;
- and
- a pass through step in which, in a case that the received data from the master device is the synchronization request data, and the slave device information contained within the synchronization request data indicates a slave device other than itself, the slave device, after having transmitted the received synchronization request data in the communication mode, controls the switching unit to switch from the communication mode to the pass through mode.
Dependencies are inferred from the claim text.