REXROTH Fv Series, Instruction Manual

Page: 191 / 222

12.2.5 ModBus Communication Example
One slave address is 01H. The frequency setting of the frequency converter
has been set to “external computer frequency setting” and the source of run‐
ning commands is “external computer control”. It is required for the motor
connected to the frequency converter to run with 50 Hz (forward rotation).
The operation can be achieved with function 0x10 of the ModBus protocol.
The messages of the requests from the master and responses from the slave
are shown in fig. 12-20 "Example of ModBus communication" on page 189 .
Example 1: Start 01# converter for forward rotation at frequency of 50.00Hz (represented by 5000 internally)
Slave ad‐
dress
Function code Start ad‐
dress
Number of ad‐
dress
Bytes of data Data content CRC code
Request 0x01 0x10 0x4000 0x0002 0x04
0x0001，
0x1388
0xFA9E
Response 0x01 0x10 0x4000 0x0002 N/A N/A 0x0854
Example 2: Read the output voltage of 01# converter and set frequency
Slave ad‐
dress
Function code Start ad‐
dress
Number of ad‐
dress
Bytes of data Data content CRC code
Request 0x01 0x03 0x5001 0x0002 N/A N/A 0xCB84
Response 0x01 0x03 N/A N/A 0x04
0x1388，
0x1388
0xCB73
Example 3: Stop 01# converter according to the stop mode set with the function code
Slave ad‐
dress
Function code Start ad‐
dress
Number of ad‐
dress
Bytes of data Data content CRC code
Request 0x01 0x06 0x4000 N/A N/A 0x0008 0xCC9D
Response 0x01 0x06 0x4000 N/A N/A 0x0008 0xCC9D
Fig.12-20: Example of ModBus communication
12.2.6 Special Notes
1. The external computer can not wirte to function codes [b0.03], [b0.08],
[b0.09] and [S2.10].
2. [b0.00] and [b0.02] do not support multiple write including single write in
multiple write; parameters of motor name plate and motor can not be
written at the same time; Terminals X1 ─ X8 can not be rewritten if they
are not 0.
3. If the communication protocol is changed, baud rate, data frame and lo‐
cal address will be restore to factory default.
4. The read response of uer password and factory password is '0000' in
case of external computer reading.
5. External computer can not set, modify or cancel user password; external
computer can only write 0 in case of no password or write correct pass‐
word in case of with password; if a password is active, the external com‐
puter only has the access to modify the parameters after input of the
correct password; After the external has the access to modify the pa‐
rameters, if the previous password is input again, the modification ac‐
cess is disabled.
6. The access to control registers and state registers is not limited by user
password.
DOK-RCON02-FV*********IB01-EN-P
Rexroth Frequency Converter Fv Bosch Rexroth AG 189/219
Communication Protocols