Long Distance 134.2Khz Modbus Card Reader

1,Communication and Protocol Description

Serial port (8 bits):

System Configuration Content(16hex)

1,Antenna switch and response mode. In the following content (active transmission from the slave), the reader will actively send tag data after reading the card. (Master-slave mode) means that the card reader will not actively return data until the host accesses it. (This configuration data is not saved when power is cut off. It needs to be configured once every time power is turned on.(16hex communication)

2,The length of data and the address of the reader in the back of the card. Back-band data means that some cards send data with other data besides the card number and country code. Current products support maximum access 20 bytes of data (160bit) This configuration data is saved without loss of power.(16hex Communication)

Read data: (16hex communication)

1. Read the antenna switch and response mode information. (hexadecimal communication)

2. After reading, the data length, address, and version number information are included. (hexadecimal communication)

3. Read system tuning status information (hexadecimal communication)

4, reading card data read: (hexadecimal communication)

The read data can be read from 0x07-0x11 (that is, the readback information address can be from (0x0E-0x15) to (0x0E-0x1F)).

Send command analysis（02 03 00 0E 00 07 65 F8）

02： Slave address

03: Read function（MODBUS-RTU）；

000E：Read register address

0007: read data length (7 words 14 Bytes);

65F8：All previous data (02 03 00 0E 00 07) CRC check value,Low byte first.

Receive command analysis: (1)02 03 0E 02 62 07 B6 60 CB 53 00 80 00 00 00 00 00 00 3E DC F6）

02: slave address;

03: Read function (MODBUS-RTU);

0E: readback data length (14 Bytes);

0262: Country code (10 hex)

07B660CB53: Card number data (10-digit 33124567891)

00:0000 0000 The lowest bit represents whether the post-add data is valid (0 is invalid, 1 is valid), and the other 7 bits are undefined data.

80:1000 0000 The highest digit represents the animal logo, and the other 7 digits are undefined data.

000000: Other data in the card, no data is defined.

00: Data transfer supplements enough for even digital sections (14 Bytes), meaningless

3E: The current data read time (0x3E*0.2s) proved to be read before 12.4s, up to 51s.

DCF6: CRC check of the entire previous packet (02 03 0E 02 62 07 B6 60 CB 53 00 80 00 00 00 00 3E). DC is the low byte and F6 is the high byte.

Receive command analysis: (02 03 22 02 62 07 B6 60 CB 53 80 80 00 00 00 11 11 11 11 22 22 22 22 33 33 24 55 25 25 45 53 55 84 53 43 FF 20 D5 CF)

02 03 22 02 62 07 B6 60 CB 53 80 80 00 00 00: Consistent with the above analysis.

11 11 11 11 22 22 22 22 33 33 24 55 25 25 45 53 55 84 53 43: 20 bytes of post added data.

FF: Data transfer supplements enough for even digital sections (34 Bytes), meaningless.

20: The current data reading time (0x20*0.2s) proved to be read before 6.4s, up to 51s.

D5CF: CRC check of the entire previous packet, D5 is the low byte and CF is the high byte.

The slave sends the message actively: the machine will send a frame of data immediately after reading the card. If the card does not leave the data, it will not be sent repeatedly. If the card leaves 0.2s or more and then enter the machine, it will send another frame of data (each card enters Will send a frame of data to the bus in real time)

When the card reader is configured as the slave active transmission mode, the card reader will send the card number information to the bus immediately after reading the card. The length of the information can be configured. For example, we will configure the post-added data length to 30 bits (16 bits or less). Do not send data after sending, the data is valid from 16-160), 35 bits are 4 bytes, 3 bits need 5 bytes to send, so the string data length is 12 (card number information length) +5=17 words Section, but since the data length number is even (word), it is necessary to add a random number, that is, 18 pieces. So the composition of the string is 0xxx (slave address) + 0x03 (function) + 0x12 (18 bytes) + 18 bytes of data + 2 bytes of CRC. A total of 23 bytes. (After adding data, if there is no need, it is better to match 0, which is good for data transmission)

For example, add data configuration A0 (160 bits, 20 bytes). The data received when the card has data added is:03 03 20 02 62 07 B6 60 CB 53 01 80 00 00 00 11 11 11 11 22 22 22 22 33 33 24 55 25 25 45 53 55 84 53 43 C1 26

03: slave address;

03: Read function (MODBUS-RTU);

20: read back the data length (32 Bytes);

0262: Country code (10 hex)

07B660CB53: Card number data (10-digit 33124567891)

01:0000 0001 The lowest bit represents whether the post-add data is valid (0 is invalid, 1 is valid), and the other 7 bits are undefined data.

80:1000 0000 The highest digit represents the animal logo, and the other 7 digits are undefined data.

000000: Other data in the card, no data is defined.

11 11 11 11 22 22 22 22 33 33 24 55 25 25 45 53 55 84 53 43: Yes, add 20 bytes of data.

C126: CRC check.

After the post-add data is configured as 0, the data is read: 02 03 0C 02 62 07 B6 60 CB 53 01 80 00 00 00 17 35

02: slave address;

03: Read function (MODBUS-RTU);

0C: readback data length (12 Bytes);

0262: Country code (10 hex)

07B660CB53: Card number data (10-digit 33124567891)

01:0000 0001 The lowest bit represents whether the post-add data is valid (0 is invalid, 1 is valid), and the other 7 bits are undefined data.

80:1000 0000 The highest digit represents the animal logo, and the other 7 digits are undefined data.

000000: Other data in the card, no data is defined.

1735: CRC check

Factory default configuration: slave address 02 plus data length 0

Reset configuration: standard master-slave mode

So if you want the card reader to read the card, send the data: after the boot, send the command: 02 06 00 00 00 03 C9 F8

This protocol complies with the MODBUS-RTU standard and supports the 0-address broadcast monitoring function (can be used to configure the slave address and other information). However, the broadcast command does not respond to the slave.

CRC Check function：

unsigned int CRC16_MB(unsigned char *cBuffer, unsigned int iBufLen)

{

unsigned int i, j;

unsigned int wPolynom = 0xa001;

unsigned int wCrc = 0xffff;

for (i = 0; i < iBufLen; i++)

{

wCrc ^= cBuffer[i];

for (j = 0; j < 8; j++)

{

if (wCrc &0x0001)

{

wCrc = (wCrc >> 1) ^ wPolynom;

}

else

{

wCrc = wCrc >> 1;

}

}

}

return wCrc;

}