Modbus communication protocol
76
F05.00 Protocol
selection
0:Modbus protocol
1:Reserved
2:Profibus protocol(expansion is valid)
3:CanLink protocol(expansion is valid)
4:CANopen protocol(expansion is valid)
5:free protocol 1(revision all the parameter of
EN600PV is valid)
6: free protocol 2(only revising part Parameter of
EN600PV is valid)
Remark: expansion card is needed when
Select 2,3,4 communication
1 0 ×
F05.01
Baud rate setting Units digit: free protocol and Modbus Baud rate
selection
0:300BPS 1:600BPS 2:1200BPS
3:2400BPS 4:4800BPS 5:9600BPS
6:19200BPS 7:38400BPS 8:57600BPS
1 005
×
F05.02
Data format
Units digit: free protocol and Modbus protocol
Data format
0:1-8-1 format, no checkout
，
RTU
1:1-8-1 format, Even Parity
，
RTU
2:1-8-1 format, Odd Parity
，
RTU
3:1-7-1 format, no checkout
，
ASCII
4:1-7-1 format, Even Parity
，
ASCII
5:1-7-1 format, Odd Parity
，
ASCII
00 ×
F05.03 Local
address 0
～
247
，
00 is broadcast address
1
1
×
A.5 Data communication structure
A.5.1 Data frame format
Using RTU mode, messages are sent at least 3.5 character time interval pause.The first
transmitted field is device address, the character you can transfer is hexadecimal 0x00 ~ 0xFF.
Network equipment Continuously monitor the bus,including pauses. When the address field is
received, all equipment determine whether it is sent to their own. when the last character of the
packet transfer is complete, at least a 3.5 character times pause mean the end of the message. A
new message can begin after this pause.
The entire message frame must be transmitted as a continuous flow. If a new message start
transmitting in less than 3.5 character times after a message and then receiving device will
consider it a continuation of the previous message. This will cause an error, because in the final
CRC field value can not be right.
RTU frame format as the table below:
Frame Header
3.5 characters time pause
Slave address
Slave address:0~247
Communication command code
03H:read slave parameter
06H:write slave parameter
Data content DATA
The contents of packet:
Parameter address(16bit);
Number of parameter or bytes of parameter
value;
Parameter value(16bit)
Data content DATA
……
……
CRC check value low byte
16bit Unsigned check value
ENC
