TP-6833 2/16
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Section 4 Communication and Accessory Connections
Section 4 Communication and Accessory Connections
4.1 Introduction
This section explains the connection of communication
cables and factory-installed accessories.
Also refer to the following documentation for instructions
to install, connect, and operate optional accessories.
D
Transfer switch wiring diagrams.
D
Installation instructions or diagrams provided with
loose accessory kits.
4.2 Communication Connections
The Decision-Maker
r
MPAC 1200 and MPAC 1500
controllers are equipped with a USB port and a Modbus
port with an RS-485 connector.
An Ethernet
communication board is standard on the MPAC 1500
controller and optional on the MPAC 1200 controller.
4.2.1
USB Port SiteTech Connection
A personal computer and Kohler
r
SiteTech
t
software
can be used for changing controller settings. Use a USB
cable to connect the controller to a personal computer.
See Figure 4-1 for the USB port location on the front of
the controller assembly. Remove the small port cover
and use a USB cable with a mini-B connector to connect
the controller’s USB port to the computer.
See TP-6701, SiteTech Software Operation Manual, for
instructions to use the software. Disconnect the USB
cable from the controller and replace the port cover
when finished.
1. USB connection (below port cover)
GM85888
1
Figure 4-1
USB Connection for SiteTech
(MPAC 1500 controller shown)
4.2.2
Modbus Connection
Hazardous voltage.
Will cause severe injury or death.
Disconnect all power sources before
opening the enclosure.
DANGER
Servicing the transfer switch. Hazardous voltage can
cause severe injury or death.
Deenergize all power sources
before servicing. Turn off the main circuit breakers of all
transfer switch power sources and disable all generator sets
as follows: (1) Press the generator set off/reset button to shut
down the generator set. (2) Disconnect power to all battery
chargers. (3) Disconnect all battery cables, negative (--) leads
first. Reconnect negative (--) leads last when reconnecting the
battery cables after servicing. Follow these precautions to
prevent the starting of generator sets by an automatic transfer
switch, remote start/stop switch, or engine start command
from a remote computer. Before servicing any components
inside the enclosure: (1) Remove all jewelry. (2) Stand on a
dry, approved electrically insulated mat. (3) Test circuits with a
voltmeter to verify that they are deenergized.
See Figure 4-2 for the RS-485 Modbus connector
location.
Use serial connections to TB2 on the controller to
connect the transfer switch to a personal computer for
system monitoring, the optional remote annunciator, or
a Modbus network. See Figure 4-4.
Notice that a 121 ohm terminating resistor is
recommended on the last device in a network. If there is
only one device, a terminating resistor may be required
depending on the cable distance and communication
speed. Long cables and high speeds will increase the
need for a terminating resistor.
The serial port is an isolated RS-485 port with
connection speeds of 9.6, 19.2, and 57.6 kbps. Use
shielded twisted-pair cable to connect to the RS-485
connectors on the controller’s terminal strip TB2 for
serial connections. For connection to a PC, use a USB
to RS-485 converter.
Connect the Modbus input and output to the terminals
shown in Figure 4-3. Use #12-24 AWG shielded,
twisted-pair wire. Belden cable #9841 or equivalent is
recommended. Connect one end of the shield to
ground. Leave the other end of the shield disconnected.
Tighten the connections to 0.5 Nm (4.4 in. lb.).
