CRC lower byte 38H
CRC higher byte E3H
End Transmission time for 3.5 bytes
Fig.13-20: Function 0x17_Request from RTU master
Start Transmission time for 3.5 bytes
Slave address 01H
ModBus function code 17H
Bytes of read register 04H
Higher byte of read register 0100H 00H
Lower byte of read register 0100H 32H
Higher byte of read register 0101H 00H
Lower byte of read register 0101H 32H
CRC lower byte D9H
CRC higher byte 3DH
End Transmission time for 3.5 bytes
Fig.13-21: Function 0x17_Response from RTU slave
Error code and exception code
If the slave receives the request without a communication error, but cannot handle it,
the slave will return an exception response which includes error code and exception
code informing the master of the nature of the error. The error code is formed by setting
the MSB of the function code to 1 (i.e. function code plus with 0x80, like 0x83, 0x86,
0x90, 0x97), then the exception response has a format shown below.
Slave No.
Error code Exception code CRC16
Lo | Hi
Exception codes for EFC 3600 frequency converters:
● 1=Parameter cannot be modify owing to user password locked
● 2=The function requested is not recognized by the slave, i.e. not equal to 3, 6, 8, 16
or 23
● 3=The word address indicated in the request do not exist in the slave
● 4=The word values indicated in the request are not permissible in the slave
● 5=Parameters cannot be modify in run mode
● 6=Parameters are read-only that cannot be modified
● 7=Invalid operation which is decided by the function of frequency converter
(*)
Bosch Rexroth AG
Communication Protocols
DOK-RCON03-EFC-3600***-IT01-EN-P
Rexroth Frequency Converter EFC 3600
180/235
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