User Manual
Chapter 8 Communication Functions
8 - 6
Message Configuration: Query
Slave address:
This is a number of 1 to 247 assigned to each inverter (slave). (Only the inverter having the
address given as a slave address in the query can receive the query.)
When slave address “0” is specified, the query can be addressed to all inverters simultaneously.
(Broadcasting)
In broadcasting, you cannot call and loop back data.
Data:
A function command is set here.
The data format used in the NE-S1 series is corresponding to the Modbus data format below.
The negative data use 2 complements.
Function code:
Specify a function you want to make the inverter execute. Function codes available to the NE-S1
series are listed below.
Function
Code
Function
Maximum data size
(bytes available
per message)
Maximum number o
f
data elements available
per message
0 1 h Read Coil Status 4 32 coils (in bits)
0 3 h Read Holding Resistor 32 16 registers (in bytes)
0 5 h Write in Coil 2 1 coil (in bits)
0 6 h Write in Holding Register 2 1 register (in bytes)
0 8 h Loopback Test
0 F h Write in Coils 4 32 coils (in bits)
1 0 h Write in Registers 32 16 registers (in bytes)
1 7h Read/Write Holding Registor 32 16 registers (in bytes)
Error check:
Modbus-RTU uses CRC (Cyclic Redundancy Check) for error checking.
The CRC code is 16-bit data that is generated for 8-bit blocks of arbitrary length.
The CRC code is generated by a generator polynomial CRC-16 (X16+ X15+ X2+ 1).
Header and trailer (silent interval):
Latency is the time between the reception of a query from the master and transmission of a
response from the inverter.
3.5 characters (24 bits) are always required for latency time. If the latency time shorter than 3.5
characters, the inverter returns no response.
The actual transmission latency time is the sum of silent interval (3.5 characters long) + C078
(transmission latency time).
Name of Data Description
Coil Binary data that can be referenced and changed ( 1 bit long)
Holding Register 16-bit data that can be referenced and changed