Hitachi SJ Series User Manual page 512

Chapter 14
14.5 EzCOM Function
14.5.1 What is EzCOM?
Q
• What is EzCOM?
A
• EzCOM is a function to allow multiple inverters to
communicate each other without a master inverter
such as PC and PLC, aside from normal
Modbus-RTU communication (slave).
• Rolls of inverters within the network of EzCOM are
allocated to:
- "Controlling inverter"
- "Master inverter"
- "Slave inverter"
• In the EzCOM network, the "controlling inverter"
designates an inverter within the network as a
"master inverter", and the "master inverter" gives
commands sequentially.
• As in the normal Modbus communication (RS-485),
connect SP and SN terminals of respective
inverters used in EzCOM communication.
Controlling inverter
(01)
: Master inverter
Inverter Inverter
(02) (03)
14-21
RS485 Communication
• A master inverter is able to write 5 different
commands to retention registers of arbitrary slave
inverters.
• Once a data transmission between a master and
slaves is completed, the controlling inverter shifts a
master inverter sequentially and repeats a data
transmission in accordance with the settings of
respective master inverters.
• "Controlling inverter" is always fixed whereas
"master inverter" is shifted sequentially. For this
reason, the "controlling inverter" can be a "master
inverter" or "slave inverter".
• Up to 8 inverters can function as a "master
inverter".
Inverter
(04)
Data is transmitted from the master of
inverter (01) to slaves.
The master is switched from (01) to (02).
Data is transmitted from the master of
inverter (02) to slaves.
The master is switched from (02) to (03).
Data is transmitted from the master of
inverter (03) to slaves.
The master is switched from (03) to (04).
Data is transmitted from the master of
inverter (04) to slaves.