Sinee EM303A-011G/015P-3CB, Руководство пользователя

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User Manual
EM303A General Purpose Inverter
133
12 Communication Protocol of EM303A
12.1 Application Scope
1. Applicable series: EM303A
2. Applicable network: Support ModBus protocol, RTU format, with single-master
and multiple-slaves communication network of RS485 bus.
The typical RTU message frame format:
Start Bit Device Address Function Code
Data
CRC Parity Stop Bit
T1-T2-T3-T4 8Bit 8Bit n*8Bit 16Bit T1-T2-T3-T4
Remarks:
It takes 8S for inverter to reset the default of F0-28, the high bytes first, then the low
bytes. The inverter would not response to communicational command in those 8S.
12.2 Physical Interface
RS485 asynchronous half-duplex communication mode
Default data format of keypad communication interface: 1-8-N-1, bits rate: 9600bps.
Default data format of RS485 terminal: 1-8-N-1
，
bits rate:9600bps.
Data format 1-8-N-1, 1-8-O-1, 1-8-E-1, bits rates: 4800bps, 9600bps, 19200bps, and
38400 bps.
12.3 Protocol Format
Command code 0x03: Read parameter and status byte of inverter.
Frame Structure of Sending Message
Transmit Sequence Bytes Sent
0 ≥ Idle periods of 4 bits
1 Address code 1
2 Function code 1
3 Register start address
（
H
）
2
4 Register start address
（
L
）
5 Register number
（
H
）
2
6 Register number
（
L
）
7 CRC parity
（
L
）
2
8 CRC parity （ H ）
9 ≥ Idle periods of 4 bits