Example of supported communications protocol
Modicon’s Modbus communications protocol:
• A Modicon-compatible PLC interface is located at each motor control center.
• The PLCs are networked to a main Modbus controller, e.g. a PC, and the communications
board on the drive.
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Note
Supported communications protocol
This section uses Modicon’s Modbus serial interface as one example of a supported
communications protocol.
Any supported communications network can be used.
The interface can also be achieved with no PLC, or by direct logic control.
8.17.10 Synchronous Transfer Operation for Synchronous Motors (L29)
Synchronous transfer with a synchronous motor (SM) is essentially the same as with an
induction motor (IM) with the addition of transfer of the control of the motor eld winding
excitor from or to the drive to or from an external source.
Also, for synchronous transfer with SMs, an analog signal from the drive is required to control the
eld current, and another analog signal from the controller to the drive, is required to read the
output of the external controller.
For handshaking with a required external controller, a minimum of two digital inputs and two
digital outputs is required to provide adequate handshaking between the drive and the external
Advanced Operating Functions
8.17 Synchronous Transfer
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