AUDAC ARU20 Series, User Manual

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15
Chapter 3
Wiring up the system
NOTE
Make sure the power of the system is switched off, when any changes to the connections
are being made.
RS485:
In case your system is using the RS485 bus protocol, avoid making any star structured
constructions in your cabling. In installations where multiple ARU’s are connected in a bus
structure it is important that the data bus is connected as a daisy chained structure and the
last device terminates the bus on its characteristic impedance through placement of the bus
termination jumper. All other devices connected in this bus structure should not have the bus
termination jumpers on off position.
The connection between the ARU’s (RS485) shall be made with twisted pair cabling (CAT5E
or higher). The Ethernet connection shall also be established with CAT5E (or higher) cabling.
Power supply (24 V DC):
The complete system can be powered using a single 24 V DC power supply. The voltage is
distributed through the RS485 databus connection and other connected ARU’s will be fed
accordingly when connected in daisy chained structure. If cable distances larger than 300
meters will occur, the cable length will make the voltage drop below the required level and
additional power supplies needs to get added locally.
Ethernet:
To establish a proper Ethernet connection, CAT5E (or higher) cabling needs to be used for
connecting the ARU to your Ethernet network.
Relay connections:
Any kind of signals within the systems limitations can be switched and controlled through
the ARU unit. Depending on the type of signal and the system regulations or restrictions, the
signals needs to be connected using the appropriate cable and wiring standards.
Contact inputs:
The contact inputs on the ARU20x are dry contact inputs which can be used for triggering
relays by external devices or actuators. The contacts are triggered by connecting the particular
terminal for the relay to ground. When triggering the triggering the ‘A’ contact, all contacts
will switch simultaneously.