Installation; Technical Data; Cables - Dräger Polytron 8000 Series Technical Manual

3

Installation

The following chapters describe the installation and configuration of the
Dräger Polytron
to as "gas detector").
3.1

Technical data

The following values apply for the gas detector:
Parameter
Number of receivers
Maximum line length
Common-mode input voltage
Input resistance of the receiver
Input sensitivity of the receiver
Differential data transmission
3.2

Cables

3.2.1 Cable type
Various cable types (type designations A to D) for different applications are
available on the market to interconnect the devices and connect them to network
elements (e.g., segment couplers, links, and repeaters). Use a type A cable for RS-
485 transmission.
The maximum length of the cables that can be used in a Modbus system is
determined by various factors. Different limitations apply for the cables and the
individual leads.
Use shielded, twisted 2-wire cables and observe the maximum cable length.
Power supply
(2-pin)
Modbus RTU
(2-pin)
Parameter
Common-mode input voltage
range
Differential output voltage
Data signal A-B or B-A
Differential input voltage
Data signal A-B or B-A
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Technical Manual
Digital Communication - Modbus RTU
®
8000 gas detector with Modbus RTU interface (hereafter referred
Terminal Tightening
torque in Nm
0.5 to 0.8
0.5 to 0.8
RS-485/EIA485
32
1000 m
-20 to +25 V
12 kOhm
+/- 200 mV
Yes
Cable cross-sec-
tion in AWG
24 - 12
24 - 12
Condition Min.
value
-20
Load R=54 ohms
Common-mode 200
voltage range
-20 V to +25 V
Installation
Cable cross-sec-
tion in mm²
0.2 to 2.5
0.2 to 2.5
Max. Unit
value
30 V
1.5 - V
- mV
15