Instruction Manual

5. Modbus RTU
80
Modbus
(4) Query sample
A sample query that reads the alarm code (address 9002
H
) of a controller with axis No. 0 is
shown below.
z Query (silent intervals are inserted before and after the query)
01 03 90 02 00 01 08 CA
Field RTU mode
8-bit data
Start Silent interval
Slave address [H] 01
Function code [H] 03
Start address [H] 9002
Number of registers [H] 0001
Error check [H] 08CA (in accordance with
CRC calculation)
End Silent interval
The response to the query is as follows.
z Response (silent intervals are inserted before and after the response)
01 03 02 00 E8 B8 0A
Field RTU mode
8-bit data
Start Silent interval
Slave address [H] 01
Function code [H] 03
Number of data bytes [H] 02 (2 bytes = 1 register)
Data 1 [H] 00 E8
Error check [H]
B80A (in accordance with CRC calculation)
End Silent interval
The most important alarm presently detected is “0E8”
H
, which is a phase A/B open alarm.
[For details on alarm codes, refer to the operation manual that comes with each controller.]
Note The data of the response example is simply an example and will vary depending on
various conditions.