N-Tron® 300 Series Hardware Guide
2-9
Installation
Revised 2015-12-04
Ground Connection
300 Series Grounding Techniques
The grounding philosophy of any control system is an integral part of the design. N-Tron 300 series switches are
designed to be grounded, but the user has been given the flexibility to float the switch when required. The best
noise immunity and emissions (i.e. CE) are obtained when the N-Tron switch chassis is connected to earth
ground via a drain wire. Some N-Tron switches have metal DIN-Rail brackets that can ground the switch if the
DIN-Rail is grounded. In some cases, N-Tron switches with metal brackets can be supplied with optional plastic
brackets if isolation is required.
Both V- legs of the power input connector are con-
nected to chassis internally on the PCB. Connecting a
drain wire to earth ground from one of the V- terminal
plugs as shown here will ground the switch and the
chassis. The power leads from the power source should
be limited to 3 meters or less in length.
As an alternate, users can run a drain wire & lug from
any of the DIN-Rail screws or empty PEM nuts on the
enclosure. When using an unused PEM nut to connect
a ground lug via a machine screw, care should be taken
to limit the penetration of the outer skin by less than 1/4
in. Failure to do so may cause irreversible damage to
the internal components of the switch.
Note:
Before applying power to the grounded switch,
you must use a volt meter to verify there is no voltage
difference between the power supply’s negative output
terminal and the switch chassis grounding point.
If the use of shielded cables is required, it is generally recommended to only connect the shield at one end to pre-
vent ground loops and interfere with low level signals (i.e. thermocouples, RTD, etc.). Cat5e cables manufac-
tured to EIA-568A or 568B specifications are required for use with N-Tron Switches.
In the event all Cat5e patch cable distances are small (i.e. All Ethernet devices are located the same local cabi-
net and/or referenced to the same earth ground), it is permissible to use fully shielded cables terminated to chas-
sis ground at both ends in systems void of low level analog signals.
