Using Modbus Communication; Modbus Communication Configuration; Communication Specifications; D. 1 Example Of Connections Between Master And Drive - YASKAWA P7 User Manual

Using Modbus Communication

Serial communication can be performed with Direct Digital Controllers (DDCs) or similar devices using the Modbus protocol.
!

Modbus Communication Configuration

Modbus communication is configured using 1 master (PLC) and a maximum of 31 slaves. Serial communication between
master and slave is normally initiated by the master and responded to by the slaves.
The master performs serial communication with one slave at a time. Consequently, the slave address of each slave must be
initially set, so that the master can perform serial communication using that address. Slaves receiving commands from the
master perform the specified functions, and send a response back to the master.
!

Communication Specifications

The Modbus communication specifications are shown below:
Interface
Communications Cycle
Communications Parameters
Communications Protocol
Number of Connectable Units
Master
Fig D. 1 Example of Connections between Master and Drive
Table D.1 Modbus Communication Specifications
Item
RS-422, RS-485
Asynchronous (Start-stop synchronization)
Baud rate:
Data length:
Parity:
Stop bits:
Modbus
31 units max.
Communications D - 2
Slaves
E7 E7
Specifications
Select from 1200, 2400, 4800, 9600, and 19200 bps.
8 bits fixed
Select from even, odd, or none.
1 bit selected
E7