YASKAWA HV600

10.6 MEMOBUS/Modbus Communications
738 YASKAWA SIEPYAIH6B01A HV600 AC Drive Bypass Technical Reference
10.6 MEMOBUS/Modbus Communications
This section gives detailed information about the parameters, error codes and communication procedures for
MEMOBUS/Modbus communications.
◆ Configure Master/Slave
You can use the MEMOBUS/Modbus protocol for serial communication with programmable controllers.
The MEMOBUS/Modbus communication uses one master and a maximum of 31 slave bypasses. Serial
communications usually starts with a signal from the master to the slave bypass.
A slave bypass that receives a command from the master does the specified function and then sends a response back
to the master. You must set the address number for each slave bypass before you start communications to make sure
that the master uses the correct address numbers.
A - Master (controller) B - Slave (bypass)
Figure 10.17 Master and Slave Connection Example
◆ Communication Specifications
Table 10.19 lists the specifications for the MEMOBUS/Modbus communications.
Table 10.19 MEMOBUS/Modbus Specifications
Item Specification
Interface RS-485
Synchronization method Asynchronous (start-stop synchronization)
Communication parameter
Communications speed:1.2, 2.4, 4.8, 9.6, 19.2, 38.4, 57.6, 76.8, 115.2 kbps
Data length: 8 bit (fixed)
Parity: even, odd, none
Stop bit 1 bit (fixed)
Communication protocol MEMOBUS/Modbus standard (RTU mode only)
Number of possible units to connect Maximum: 31 units
◆ Communication with the Controller
This section gives information about the settings for the termination resistor and how to connect to MEMOBUS/
Modbus communications. MEMOBUS/Modbus communications uses an RS-485 interface (2-wire sequence).