Serial Connections - Kohler MPAC 1500 Manual

6.2.1

Serial Connections

Use serial connections to TB2 on the controller's logic
board to connect the transfer switch to a personal
computer, the optional ATS remote annunciator, or a
Modbus network. System monitoring and control using
Kohlerr Monitor III software requires serial connection
to a personal computer as described in this section. See
Figure 6-1 for the location of TB2.
See Figure 6-2. Notice that a 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 fast speeds will increase the
need for a terminating resistor.
RS-232
RS-232 to RS-485
port converter
PC
Terminating resistor
may be required
RS-232
RS-232 to RS-485
port converter
PC
Terminating
resistor, 121 Ohms
Figure 6-2 Serial Connections
94 Section 6 Communications
RS-485
In Device
Out
RS-485
In
Device
Out
In
Device
Out
In
Last
Device
Out
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 main logic board terminal strip TB2 for
serial connections. For connection to a PC, use an
RS-485 to RS-232 converter GM41096 and connect to
the PC's serial port.
Connect the Modbus input and output to the terminals
shown in Figure 6-3. Use #12-24 AWG twisted-pair
wire. Belden cable
recommended. Connect the shield to ground. Tighten
the connections to 0.5 Nm (4.4 in. lb.).
Use Modbus RTU (remote terminal unit) protocol for
communication through the serial port. A map of the
Modbus codes for this controller is available. Contact
your local distributor/dealer.
Note: Modbusr applications other than Monitor III
software require a Modbus software driver
written by a trained and qualified systems
programmer.
Input
1
4
Output
Customer connections
Figure 6-3 Main Logic Board Modbus RS-485
Connections to TB2
#9841 or equivalent
3
TB2
6
TP-6714
is
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