N-Tron 7026 Series User Manual & Installation Manual page 14

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. In the case of both the DC and AC Power supply options for the
7026TX/7026TX-AC the power supply is isolated from chassis ground. Therefore the user must not attempt
to ground the switch to earth ground via the power supply. In other N-Tron switches it is common to use
the V- for the purpose of grounding. This must NOT be attempted in the 7026TX or 7026TX-AC.
In the case of the AC power supply option (i.e., 7026TX-AC) the
chassis may be connected to earth ground using the safety input of
the input power plug labeled ―GND‖ (refer to the drawing above
which shows the pin out of the AC power plug) or using the
ground lug located at the rear of the chassis (see adjacent
illustration).
In the case of the 7026TX, the only viable safety ground option is
using the ground lug at the rear of the chassis (see adjacent
illustration).
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.
Page 14 of 169
(Revised 2011-11-15)
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