Unitronics UIS-04PTN User Manual page 7

UIS-04PTN, UIS-04PTKN
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 cables for wiring RTD signals;
do not use the cable shield as a signal common (CM) / return path.
▪ Individually connect each functional ground point ( ) to the earth of the system (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 2 ).
▪ 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; typically, earthing the shield
at the Uni-I/O™ end performs better.
Keep shield connections as short as possible.
➢
Ensure shield continuity when extending shielded cables.
➢
For detailed information, refer to the document System Wiring Guidelines, located in the
N
OTE
Technical Library in the Unitronics' website.
Wiring the RTD Inputs
▪ The inputs are not isolated.
N
OT
▪ When connecting 3- or 4-wire RTDs, make sure to use conductors of the same type, width,
E
and length for all RTD wires, otherwise module accuracy will degrade.
▪ When connecting 4-wire RTDs, use 3-wire cable and leave the unused wire unconnected with
minimal length.
Unitronics
User Guide
7