System information

Table Of Contents
Document Part # 026-4122 Rev 1 16-JUN-2008 Page 3 of 10
©2008 Emerson Climate Technologies Retail Solutions, Inc. This document may be photocopied for personal use.
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Control Techniques VSD Interface to E2
technical bulletin
For both MODBUS and 0-10VDC, connect B2 and B4 terminals to a relay on a MultiFlex or 8RO board to con-
trol the ENABLE signal, or simply jumper B2 and B4 to enable the drive.
Figure 1 - Commander SK Drive Wiring (Analog and MODBUS)
For wiring information for Commander SE and Unidrive SP models of VSD, refer to the VSD documentation.
MODBUS Networking
Control Techniques drives connect to an E2 using an RS485 network. Multiple VSDs must be interconnected in
a daisy-chain without branches or star configurations, as shown in Figure 2. Use only Belden 8761 shielded two-
wire cable or equivalent.
Figure 2 - MODBUS Daisy Chain for CT VSD Drives
Warning! Consult the Control Techniques technical manual for your
drive(s) for proper wiring, grounding, and noise prevention. Failure to
do so may result in excessive noise disrupting RS485 communication.
Warning! Use only Belden 8761 or equivalent for networking the
VSDs. CAT5 cabling and other cable that typically uses RJ45 connec-
tors like the one on the VSD are not rated for use with VSDs.
T1
T2
T3
T4
B1
B2
B3
B4
B5
B6
B7
T1
T2
T3
T4
B1
B2
B3
B4
B5
B6
B7
0-10VDC Analog Control MODBUS Control
SHIELD
SHIELD
-
+
ANALOG
POINT
(I/O BOARD)
BELDEN 8761 OR EQUIVALENT
WHITE
BLACK
DRIVE
ENABLE/
DISABLE
FWD/RUN
DRIVE
ENABLE/
DISABLE
COMMANDER SK DRIVE WIRING