Details about Function Parameters
139
FF-08
Communication Frequency Setting
Proportion
Factory
Settings
1.
00
0
Modification
○
Setting
Range
0.001
~
30.000; the communication frequency settings multiplied by this parameter are
equal to the set frequency
The RS485 Modbus protocol of the SB200 inverter series comprises three layers: physical layer,
data link layer and application layer. The physical layer and the data link layer adopt the
RS485-based Modbus protocol. The application layer is used to control such inverter operations
as operation, shutdown and parameter reading/writing.
The Modbus protocol is a master-slave protocol. There are two communication types for
master-slave communication: 1. the master sends requests and the slave responds; 2. the master
broadcasts and the slave does not respond. At any time, the bus can have only one sending device.
The maser makes a poll on the slave, which can not send messages without obtaining the
command from the master. If the communication is incorrect, the master can send the commands
once again. If there is no response from the slave within a specified time, the master will treat the
polled slave as being missing. If the slave can not execute a message, an abnormality message
will be sent to the master. Direct communication is not available between the master and the
slave. The data of a slave must be read by a master before they are sent to another slave.
The read-in of inverter parameters via communication can only modify values in the RAM. If
parameters in the RAM need to be read into the EEPROM, the “EEP Read-In Command” (The
Modbus address is 3209H) of the communication variable must be modified to1 via
communication.
Inverter Parameter Addressing Mode: The 8 higher bits of a 16-bit Modbus parameter address are
formed by the group number of the parameter and the 8 lower bits are formed by the in-group
serial number. The address mode adopts the hexadecimal system. For example, the address of
Parameter F4-17 is 0411H. For communication variables (control words and status words), the
parameter group number is 50(32H). NOTE: Communication variables include accessible
inverter parameters, communication-specific command variables and communication-specific
status variables. The parameter group numbers corresponding with the menu codes are
represented in the following table:
Menu
Code
Parameter
Group
Number
Menu
Code
Parameter
Group
Number
Menu
Code
Parameter
Group
Number
Menu Code
Parameter
Group
Number
F0
0 (00H)
F5
5 (05H)
Fb
10 (0AH)
FU
15 (0FH)
F1
1 (01H)
F6
6 (06H)
FC
11 (0BH)
Communication
Variable
50 (32H)