Vacon optea - Example 3 - Exception Response

7
vacon • 92 Modbus TCP / Modbus UDP
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7.6.3 Example 3 - Exception response
In an exception response, the Slave sets the most-significant bit (MSB) of the function code to 1. The
Slave returns an exception code in the data field.
Command Master - Slave:
Message frame:
Exception response
Answer Slave - Master:
Reply frame:
ADDRESS 01 hex Slave address 1 hex (= 1)
FUNCTION 04 hex Function 4 hex (= 4)
Starting address HI 17 hex Starting address 1770 hex (= 6000)
DATA Starting address LO 70 hex
No. of registers HI 00 hex
Invalid number of registers 0005 hex (=
5)
No. of registers LO 05 hex
ERROR CHECK CRC HI 34 hex
CRC LO 66 hex CRC 3466 hex (= 13414)
01 04 17 70 00 05 34 55
ADDRESS 01 hex Slave address 1 hex (= 1)
FUNCTION 84 hex Most significant bit set to 1
DATA Error code 04 hex Error code 04 => Slave device failure
ERROR CHECK CRC HI 42 hex
CRC LO C3 hex CRC 42C3 hex (= 17091)
01 84 04 42 C3