Inovance H3U Series - Setting the Modbus Configuration Table

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9 Communication9.5.2 Setting the Modbus Conguration Table
9.5.2 Setting the Modbus Conguration Table
In the
Project Manager
window, double-click
Modbus Conguration
.
You can click
Add
to add communication conguration items. The data in the table can be edited. All items
are operands required by instructions shown in the Modbus ladder chart, which must be entered based
on desired operations and D variables. Click
OK
. When downloading user programs, download Modbus
congurations.
1) Tips and suggestions for completing the Modbus conguration table
Slave station number (H) and register address (H) are hexadecimal.
Example 1: If the register address is 18, the station number is 12.
Example 2: To access the AC drive parameter number F0-24, enter F018 as the slave register address.
Two communication modes are available: cyclic and triggered modes. It is recommended that you classify
data based on the usage frequency.
a) Cyclic communication
To repeatedly and quickly read and write variable data of slave stations (for example, operating frequency
and state of AC drives, and state of input ports), or to change the operating frequency of AC drives and
state of output ports in real time in process control systems, you can select cyclic communication. When
the PLC executes user programs, it repeatedly scans and executes all items for cyclic communication in
the conguration table.
b) Triggered communication
To regularly read or write stable data of slave stations (for example, output current and output power of AC
drives, and active fault alarms), you can select triggered communication. When the trigger ag is set, the
corresponding items in the conguration table will be triggered. You can regularly set the ag to read or
write data.
2) Suggestions for setting the communication mode
Select the communication mode based on the data update frequency so that communication can
be signicantly improved. Do not select the cyclic mode for all communication operations to simplify
programming; otherwise, data may not be exchanged timely because of too many cyclic operations, which
will affect control. Select the triggered mode for unimportant access because triggering communication in
order of priority can signicantly improve timeliness.