Safety Instructions

SYMEO LPR
®
LPR-1D
Product Documentation
Protocol Description Binary XP (1D messages)
Copyright © Symeo GmbH 2010
Page 67 of 87
7 Protocol Description Binary XP (1D messages)
7.1 General Description
This protocol describes the interface between a LPR
®
-B station and the user. The binary
protocol XP protocol provides information in high density. Its structure ensures a simple
implementation. The transfer is done in single data frames.
The interface for the binary protocol XP can either be a serial (RS232) interface or a TCP/IP
or UDP interface. The baudrate of the serial interface must be set to 115200 baud.
7.1.1 Direction of Data
The interface can be applied bidirectional. However certain data types are defined for one
direction. Furthermore it is only allowed to send data to a LPR
®
-B station after the LPR
®
-B
station has sent a send request (type 0x02). Table 1 shows an overview which data packets
can be applied in which direction.
Data Type
direction
from LPR
®
-B
to LPR
®
-B
0x00 Distance Data
+
0x01 User Data
+
+
0x02 Send Request
+
0x03 Relay Switching Command
+
Tab. 1: direction of data
Sending data to the LPR
®
-B station is only possible after receiving a send request (Type
0x02-to-LPR
®
-B
station. The LPR
®
-B can only handle one data packet from one user.
If nevertheless data is sent to the LPR
®
-B station without a previous send request, it can
result in a reboot of the LPR
®
-B station.
Per one send request the user can send only one data set to the LPR
®
-B station.
7.1.2 Structure of Data Packet
To apply the protocol on a RS232 interface each data packet starts and ends with a reserved
symbol. This reserved symbol cannot appear in the data stream.
Figure 1 shows the general structure of the data packet.
TYPE DATA
START
0x7e
1 byte 1 byte 1 byte
CRC
2 byte
END
0x7f
Figure 1: Structure of data the packet
The START and the STOP-field is in each data packet the reserved symbol 0x7e and 0x7f.
TYPE indicates the type of the data packet. There can be defined up to 256 different types.