Vsd Drive Grounding Practices - Emerson E2 Einstein Manual

example, if the power connector is grounded against
the panel chassis, ground the network wires to the
same chassis. Keep the total exposed length of the
shield wire as short as possible (three inches ideal
length). For breaks in the middle of the segment, twist
the two shield wire ends together, and connect them
both to the same earth grounded point.
4. At the E2, remove the network cable shield wire(s)
from the 0V (center terminal) of the RS485 network
connector (leave nothing connected to the 0V termi-
nal).
5. Strip the cable jacket and shielding at the point where
the cable(s) enter the E2 enclosure. Connect the
wire(s) to the same earth ground the "GROUND"
connector is connected to. For example, if the E2's
"GROUND" power connector is grounded against the
panel chassis, ground the network wires to the same
chassis. If the E2 is not at the end of the network seg-
ment, the shield wire of both cable segments leading
to the I/O connector must be earth grounded outside
E2 ENCLOSURE
E2 PIB
RS485 (COM 2) ECHELON
Figure 7-2 - RS485 Network Segment Grounding Practices (E2 and MultiFlex)
7.4. VSD Drive Grounding
Practices
Due to noise concerns, it is recommended that all
I/O devices networked or connected to a VSD drive
follow the guidelines for EMI-resistant network
device grounding (see Section 7.3.).
12 • E2 Controller Wiring Practices
GROUND 24VAC
the E2 enclosure. Twist the two shield wires together
and connect them both to the same earth grounded
point.
Do NOT connect network shield wires to the
GROUND connector on the E2 PIB! I/O and
MODBUS network wires must be grounded sepa-
rately from the EARTH GROUND connector as
shown in Figure 7-2.
Steps 2 and 3 may be followed for any and all
network devices on an RS485 I/O or MODBUS net-
work segment. If a source of noise cannot be found,
or if the network in general is exposed to high EMI, it
is recommended all network shield wires be discon-
nected from the 0V terminals and earth grounded
near the device. Figure 7-2 shows an example of an
EMI-resistant E2 networked with MultiFlex boards,
with each device grounded properly.
MULTIFLEX
SHIELDS
For Control Techniques SK3500 series VSDs
and Unidrives, you must connect the 0V terminal of
the drive to the earth grounded chassis of the drive
with a 14AWG stranded wire. See Control Tech-
niques Technical Notification T080101 (included for
your convenience at the end of this document).
For all other VSD types, refer to the manufactur-
ers' instructions before grounding the 0V terminal.
MULTIFLEX
SHIELD
026-1903 Rev 4 19-APR-2010