Unitronics UniStream PLC Series Installation Manual page 8

Wiring Guidelines
In order to ensure that the device will operate properly and to avoid electromagnetic
interference:
 Use a metal cabinet. Make sure the cabinet and its doors are properly earthed.
 Use wires that are properly sized for the load.
 Use shielded twisted pair cables for wiring High Speed and Analog I/O signals.
Use shielded cables for wiring thermocouple and RTD signals.
In either case, do not use the cable shield as a signal common / return path.
 Route each I/O signal with its own dedicated common wire. Connect common wires
at their respective common (CM) points at the controller.
 Individually connect each 0V point and each common (CM) point in the system to the
power supply 0V terminal, unless otherwise specified.
 Individually connect each functional ground point (
(preferably to the metal cabinet chassis).
Use the shortest and thickest wires possible: less than 1m (3.3') in length, minimum
thickness 14 AWG (2 mm
 Connect the power supply 0V to the earth of the system.
 Earthing the cables' shield:
Connect the cable shield to the earth of the system (preferably to the metal cabinet
chassis). Note that the shield must be connected only at one end of the cable; it is
recommended to earth the shield at the PLC-side.
Keep shield connections as short as possible.
Ensure shield continuity when extending shielded cables.
For detailed information, refer to the document System Wiring Guidelines,
N
OTE
located in the Technical Library in the Unitronics' website.
Wiring the Power Supply
The controller requires an external power supply.
 In the event of voltage fluctuations or non-conformity to voltage power supply
specifications, connect the device to a regulated power supply.
Connect the +V and 0V terminals as
shown in the accompanying figure.
Connecting Ports
 Ethernet
 USB Device
 USB Host
8
2
).
CAT-5e shielded cable with RJ45 connector
Use a standard USB cable, Type mini-B
Standard USB Type-A plug
) to the earth of the system
®
UniStream PLC
Unitronics