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Design and Functions
9.5.3
Pin Assignment
9.5.3.1
RS-485 Interface
The internal termination resistor of the RS-485 bus is assembled in all sensors with RS-485 interface, even when
it is not explicitly stated in the interface options (
7 Type Designation). The bus must be terminated also on the
side of the evaluation unit.
WARNING!
In order not to jeopardize the safe communication between the sensor
and the evaluation unit, the RS-485 connection has to be realized as a
point-to-point connection. Apart from the sensor and the evaluation
unit, no other devices shall be connected to the bus!
Table 3: Pin Assignment RS-485 Interface
Connection Type
Connection option acc.
to type designation
Drawing
Assignment
Circular plug
M12
A-Coded
M12M
1
+24 VDC
2
0 V
3
RS-485+
4
RS-485-
5
Output door zone indication
9.5.4
Protocol Descriptions
9.5.4.1
RS-485 Interface
The communication between the sensor and the evaluation unit is bidirectional. The sensor sends the position
information and receives the floor information.
9.5.4.1.1
Interface Parameters
For a correct transmission of the data, the interface in the evaluation unit must be set to the following parame-
ters:
115200 bps
8 data bits
No parity bit
1 stop bit
No flow control
9.5.4.1.2
Structure of a Message
A message consists of six segments and has an overall effective length of 88 bits. It is divided into 11 symbols of
8 bits each. The first three segments A to C are sent by channel A, the other three segments D to F by channel B.
Fig. 25: Structure of a RS-485 message
The different segments carry the information according to the following table. You can find a more detailed
description of the content of the segments in the following chapters. Segments A to D contain the safety-relevant
information.
Table 4: Description of the segments in an RS-485 message
Segment Length in bits
Content
A
8
Message counter
1
2
3
4
5
A B
C
D
E
F
t
bus data
