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Host message format sent:

Sensor response message format returned:

◎CRC checksum

Host or sensors available checksum discriminate receiving information is correct. As electronic

noise or some other interference during the transmission of information is sometimes an error occurs,

the error check code (CRC) can test the host or sensor information in the communication data

transfer process is wrong, wrong data can give (either sending or receiving), thus increasing the

safety and efficiency of the system.

CRC I C-Mod Bus communication protocol (cyclic redundancy code) contains two bytes, or

16-bit binary number. CRC code by the sending device (host) calculations, send the information

placed in the rear frame, I C address is not included in the CRC calculation. Whether sending or

receiving CRC are by the low byte first, high byte format for transmission in the post. Receiving

information on the device (sensor) to recalculate the information received CRC, the CRC is

calculated by comparing the received query, and if they do not match, then the error. Users need

special attention, reading sensor command without adding the CRC; writing sensors must be added

the CRC; and all the return data are CRC.

◎CRC code calculation method

1. Preset a 16-bit register hexadecimal FFFF (including 1); said this register for the CRC

register;

2. The low (first byte frames both communications and information) first 8-bit binary data

with 16-bit CRC register eight or different, the results put in CRC register;

3. The contents of the CRC register right one (towards low) with zeros to fill the highest

position, and check out bit right after;

4. If the bit is 0 out: Repeat steps (the right one again) 3; If the bit is shifted 1: CRC register

with the polynomial A001 (1010 0000 0000 0001) XOR;

5. Repeat steps 3 and 4 until the right eight times, so that the entire eight were processed all

the data;

6. Repeat steps 2 through 5, the communication of information to the next frame byte

2

2

Starting address

1

0x10

Start address of the register to be written

Save word length

1

0x02

Save the data word length (2 words)

Save Data1

1

0x01

Save the data (address: 10)

Save Data2

1

0x02

Save the data (address: 11)

CRC code

2

C092

Host calculated CRC code, low byte first(C

addresses are not included in the CRC calculation)

Slave response

Byte count

Transmitting information

Remarks

Function Code

1

0x10

Write Multiple Registers

Starting address

1

0x10

Starting address saved

Save the data length

1

0x10

Save the data length sensor

CRC code

2

0x10

Sensors calculate the return CRC code, low byte first

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Enterprise QQ: 4006305378

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