FP5/GP5 User’s Manual 61
Chapter 3 - Programming Features
FP5/GP5 Operation
MODBUS Communication
The FP5/GP5 can perform serial transmission by using a program-
mable controller (PLC) and MODBUS communication. MODBUS is
composed of one master PLC and 1 to 31 (maximum) slave inverters. In
signal transmission between master and slave units, the master unit
always starts transmission and the slave units respond to it.
The master unit performs signal transmission with one slave unit at a
time. Hence, different address numbers must be assigned to each slave
unit in advance and the master unit specifies a number to perform signal
transmission. The slave unit which receives the command from the master
unit executes the function and returns the response to the master unit.
Communication Specifications
· Interface: RS-485, RS-422 (communication interface
card SI-K2/P must be mounted.)
· Synchronization: Asynchronous
· Transmission parameter: Baud rate: selectable from 2400, 4800,
9600 BPS (parameter n105)
Data length: fixed at 8 bits
Parity: parity/no parity, even/odd
selectable (parameter n106)
Stop bit: fixed at 1 bit
· Protocol: In accordance with MODBUS
· Maximum number of
units to be connected: 31 units (when RS-485 is used)
Data to be Sent/Received by Communication
Data to be sent/received by communication are run commands, frequency
reference, fault contents, inverter status and parameter setting/reading.
· Operation Mode Selection (n002, Oper Mode Select)
Select the run command and frequency reference input method in
parameter n002. To provide a run command and/or frequency reference
by communication, set this parameter to a selection that contains
“COM” for SEQ and/or REF. Regardless of this selection, monitoring
of running status, parameter setting/reading, fault reset and multi-func-
tion input commands from the PLC are possible. The multi-function
input command becomes “OR” with the command input from control
circuit terminals S2 to S6.
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