REXROTH Fv Series, Instruction Manual

Page: 183 / 222

Function
code
Description Broadcast Maximum value of
N
16=0x10
Rewrite N registers with information
stored even after power off
YES
16 characters in
maximum
23=0x17 Read from and write to N registers NO
16 characters in
maximum
Fig.12-3: ModBus functions managed by Fv converters and their limits
“Read” and “Write” is considered from the prospect of the master
station.
If the device fails to act upon the request, it responds with an error code and
exception code. The error code is the function code plus 0x80. An example of
exception code is shown in fig. 12-4 "Error codes_meanings_reasons" on
page 181 .
Error code Meaning Reason
1 Password locked User password locked
2 Function code error Function code is not 03, 06, 08, 16, 23
3 Invalid address Undefined address
4 Invalid data Data exceeds limit
5
Parameters can not be
modified in run mode
Converter is in run mode
6 Read only
Not allowed to write in read only parame‐
ters
7 Invalid operation
Function code does not support write via
external computer or multiple write
8 CRC check failure Data error or discontinuous frame
9 EEPROM read/write error EEPROM write does not finish
Fig.12-4: Error codes_meanings_reasons
Function Description
● Function 0x03: Read N words, range: 1 ─ 16.
For example, it is necessary to read 2 continuous words starting from com‐
munication register 0100H of the slave converter addressed at 01H. The
frame structure is described in fig. 12-5 "Function 0x03_master request" on
page 181 and fig. 12-6 "Function 0x03_slave response" on page 182 .
Start Transmission time for 3.5 bytes
Slave address 01H
ModBus function code 03H
Higher byte of start address 01H
Lower byte of start address 00H
Higher byte of data 00H
Lower byte of data 02H
DOK-RCON02-FV*********IB01-EN-P
Rexroth Frequency Converter Fv Bosch Rexroth AG 181/219
Communication Protocols