B&B Electronics 7506GX2-SX - Manual - Manual (Page 15)

(Revised 2010-7-30) Page 15 of 158
N-TRON SWITCH GROUNDING TECHNIQUES
The grounding philosophy of any control system is an integral part of the design. N-Tron 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.
Users may run a drain wire & lug from the screw provided on the back face of
the enclosure. In the event the provided grounding screw has been lost, care
should be taken to limit the penetration of the outer skin by less than 1/4".
Failure to do so may cause irreversible damage to the internal components of
the switch.
Note: Ensure the power supply is grounded properly before applying power to
the grounded switch. This may be verified by using a voltmeter to determine
that there is no voltage difference between the power supply’s negative output
terminal and the chassis grounding point of the switch.
As an alternative grounding method, both V- legs of the power
input connector are connected 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.
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
prevent ground loops and interfere with low level signals (i.e. thermocouples, RTD, etc.). Cat5e cables
manufactured 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 in the same local
cabinet and/or referenced to the same earth ground), it is permissible to use fully shielded cables terminated
to chassis ground at both ends in systems void of low level analog signals.
DRAIN WIRE WITH LUG CONNECTING SWITCH
CHASSIS TO KNOWN GOOD GROUNDING POINT.
DRAIN WIRE WITH
LUG CONNECTING
SWITCH CHASSIS
TO KNOWN GOOD
GROUNDING
POINT.
METALLIC
DIN-RAIL CLIP