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Modbus message, 3 exception codes (ec) – Lenze ESVZAR0 RS-485 User Manual

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CMVMB401C

Modbus Message

6.2

Register Writing

6.2.1 Message structure for reading one word

All writable registers

W

SA

06

RH

RL

DH

DL

CRCH

CRCL

RS

SA

06

RH

RL

DH

DL

CRCH

CRCL

6.3

No Response Conditions
The drive will not respond to any message that:
• contains one or more parity errors
• has an invalid CRC value
• was not directed to the drive’s network address.
• This drive does not support the broadcast function of the Modbus protocol.
• is not at least 8 bytes long (minimum required for the supported functions)
• is more than 18 bytes long (maximum allowed before input buffer overflow occurs)

6.4

Exception Responses
If a valid message is received (i.e. parity, crc, address and message length all pass validity checks), but the message
contents are somehow invalid, the drive will respond with a Modbus exception.

6.4.1 Message structure for an exception response to a read request (03)

W

SA

83

EC

CRCH

CRCL

6.4.2 Message structure for an exception response to a write request (06)

W

SA

86

EC

CRCH

CRCL

6.4.3 Exception Codes (EC)

EC

Description

01

Command rejected; Illegal function

02

Invalid register number

03

Data value is out-of-range

04

Wrong data format

06

Slave device (drive) busy