Wiring Instructions
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netTAP NT 50 | Gateway Devices
DOC091202UM09EN | Revision 9 | English | 2013-02 | Released | Public
© Hilscher, 2010-2013
10.9 RS-485
Device Damage!
!
Make sure that the NT 50 device and the remote device via RS-485
have the same potential or insert a galvanic isolation, to avoid compen-
sation current between the used devices.
The lines of this industry bus interface are operated in push-pull action, only
two lines are required which can be controlled in half duplex or full duplex
mode. The advantage of the 2-wire technology mainly consists in the multi-
master capability. In principle, each participant is able to exchange data
with any other participant. However, synchronous send attempts of two or
more participants must be prevented by the applied protocol. The RS-485
interface allows the connection of up to 32 transmitters and receivers using
a protocol. (With repeaters even more participants are possible.)
Nowadays, RS-485 supports cable lengths of up to 1.2 km (see
Lengths on page 82) and data transmission rates of up to 1
MBit/s. The maximum useable transmission rate depends on the technical
data of the used devices.
The following illustration shows wiring for RS-485:
Figure 18: RS-485 Wiring
