HERMOS LFM LP Reader - Page 73

Protocol description ASCII, SECS/HSMS
Customer manual
Version 1.2
LFM LP Reader 15.01.2019
Page 73 of 119
HERMOS AG
Gartenstrasse 19 Tel. +49(9279) 991-0
D-95490 Mistelgau Fax. +49(9279) 991-100
Direction reading device to host 0x8100
Direction host to system (reading device) 0x0100
The W bit indicates whether the transmitter of the primary message wait for a reply. If the W bit
contains the value 1, it means that a reply is expected.
The message ID determines the format and the content of the transmitted message. It consists of a
stream and a function. The stream defines the message group and the function, the exact meaning and
the syntax of the message. A primary message (request) is defined as an uneven message. A
secondary message is defined as an even message (reply).
The end bit indicates whether a block is the last block of the message. A value of 1 means that the
block is the last block. Since all messages can be transmitted in a block, the block number always
has the value 1.
The system bytes in the header of each message are used to distinguish primary messages. The
system bytes of the reply message must correspond to the system bytes of the corresponding primary
message. The system bytes are incremented for each primary message.
The checksum is calculated as the numerical sum of the unsigned binary values of all bytes – after the
length byte and before the checksum as well as in an individual block.
For more detailed information about the structure and transmission procedure, see SEMI E4 , E5 , E37 ,
E99.
(SEMI Equipment Communication Standard Message Transfer SECS