User's Manual

Brooks Automation
260301 Revision A 53
ATR60LF RFID Reader CAN Bus 7 Operation
Product Manual 7.5 Operation of the SECS Protocol
Control characters The four standard handshake codes used in the block transfer protocol are
displayed in the table below.
Message block
structure
SECS message blocks have the following form:
The operation of all communication functions above the block transfer
protocol is linked in information contained in a 10-byte data element, called
the header.
The header is always the first 10 bytes of every block sent by the block
transfer protocol.
The length includes all bytes sent after the length byte, excluding the two
checksum bytes. The maximum block length allowed by SECS-I is 254
bytes and the minimum is 10 bytes.
<ENQ> 0x05 Request to send
<EOT> 0x04 Ready to receive
<ACK> 0x06 Correct reception
<NAK> 0x15 Incorrect reception
Byte
ms
b
Description
Length 0 Length without checksum, 10 - 254
Header
1 R Upper device ID
2 Lower device ID
3 W Upper message ID (Stream)
4 Lower message ID (Function)
5 E Upper block number
6 Lower block number
System
bytes
7 System byte 1
8 System byte 2
9 System byte 3
10 System byte 4
Text 11 - 254 Message text, user data
Checksum 255, 256 16-bit unsigned checksum