Power Electronics SD 300 Series, Getting Started Manual

Page: 227 / 354

POWER ELECTRONICS SD300
MODBUS COMMUNICATION
225
Modbus Function Code Nº 16: Registers Writing
This function code allows the Modbus controller (master) to write the
content of the data registers indicated in the drive (slave). whenever those
registers are not of Read only. Registers writing by the master does not
impede the later modification of those registers by the slave.
The implementation of this function code in the drive allows writing up to 5
registers of the drive in a single frame.
Next is shown a frame where the master tries to write the content of 1
register that stores the acceleration time. The information that should be
sent in the request frame is the following:
•
Data address of the slave.
•
Modbus function code (16 Registers writing).
•
Starting Data Address.
•
Registers number for writing.
•
Bytes number for writing.
•
Content of registers for writing.
•
CRC-16 code.
The answer of the slaves includes:
•
Data address of the slave.
•
Modbus function code (16 Registers writing).
•
Starting Data Address.
•
Written registers number.
•
CRC-16 code.