Connections
AI208-6
AI208-7
AI208-4
AI208-8
AI208-9
8/10 page KKAI208C01A-A1-20140904
Note: If there is any change, please subject to the drawing on the meter
Methods of simple fault
Display
LLL/HHH
Methods
Checks whether the input disconnection and whether normal of FH value,FL value,working environment
temperature and whether collect of input signal.
Communication procotol
Meter use Modbus RTU to do RS485 half-duplex communication.Reading function ID:0x03,writing function ID:0x10/0x06.The meter use 16digits CRC to check
and will not feedback any information of checked error.
Data frame format:
1
、
Read register
Meter ADD
Function ID
Start ADD
High bit
Start ADD
Low bit
Data byte
Length/high bit
Data byte
Length/low bit
CRC code
low bit
CRC code
low bit
Host request
（
Read multi-register
）
For example:Host reads integer SV(set value 200
）
The ADD code of SV is 0x2000
，
because SV is integer(2 dyte),seizes 2 data register.The memory code of decimal integer 200 is 0x00C8
Note:It should read DP value or ensure DP value in first to ensure the decimal point when reading data,and need to transform the reading data to get the actual value.
Conversely,it should transform the data to corresponding ratio before writing the data in meter.
Start bit
Data bit
1
1 2 3 4 5 6 7 8
0x01 0x03 0x20 0x00 0x00 0x01 0x8F 0xCA
8
1
No
Stop bit
check bit
Handling of abnormal communication
If there is abnormal response
，
put the function ID on the top position 1.For example:Host request the function ID 0x03,and the function ID 0x84 will be back from host.
0x02---Illegal data reading location:data position of host beyond the address range of meter.
0x03---Illegal data writing location:writing data address of host beyond the writing address range of meter.
Communication cycle
：
Communication cycle is the time from host request to client back to data:communication cycle=time of time of client rtime of relay+time of back
Eg:9600 Baud rate:communication cycle of single measured data >250ms.
