HERMOS LFM 4x - Page 80

HERMOS AG
Gartenstraße 19 • 95490 Mistelgau
Phone: +49 9279 991 - 0
E-mail: rfid@hermos.com
LFM 4x Reader Rev1.4
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Customer manual
LFM 4x Reader
RFID
WE GENERATE SOLUTIONS
Byte
MSB
Description
Length
0
Length without
checksum
Header
1
R
Upper Device ID
(reader-ID)
2
Lower Device ID
(gateway-ID)
3
W
Upper Message ID
(stream)
4
Lower Message ID
(function)
5
E
Upper block number
6
Lower block number
7
System byte 1
8
System byte 2
9
System byte 3
10
System byte 4
Data
11-254
Message data
Checksum
255, 256
16 Bit checksum
The length contains all the bytes transmitted after the length byte with the exception of the two
checksum bytes. The maximum block length allowed by the SECS-I is 254 bytes and the
minimum is 10 bytes.
The reverse bit (R bit) indicates the direction of the message. The R bit (MSB) is set to „0“ for
messages to the reading device and „1“ for messages to the host.
The device ID is a unique number to establish the connection with the reading device. It
consists of an 8-bit gateway ID (bit 0-7) and a 7-bit reader ID (bit 8-14). The gateway ID in the
delivery state corresponds to the last two hexadecimal characters of the serial number of the
reader. The reader ID has the value 0x01 in the delivery state. Of course, the device ID can be
changed via the corresponding parameters Gateway ID and Reader ID within the validity range.
See example with Reader ID 0x01 and Gateway ID 0x00:
Upper Devic-ID (Reader-ID)
R-Bit 0 0 0 0 0 0 1