Kohler KBS - Page 32

TP-6835 9/1732 Section 4 Communication and Accessory Connections
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 require a Modbus
software driver written by a trained and qualified
systems programmer.
1. RS-485 Modbus connections
2. Access opening for RS-485 cables
GM85884
1
2
Figure 4-2 Modbus Connections (controller cover
removed for illustration only)
TB2
A1 (--) B1 (+) GND1
3
6
1
4
A1 (--)
B1 (+)
GND1
Customer connections
Input
Output
Cable shield
Cable shield
Figure 4-3 Modbus RS-485 Connections
USB to RS-485 port
converter
RS-485 *
USB port
Device
USB port
Device
Last
Device
RS-485 *
RS-485 *
Device
Terminating resistor [,
(121 Ohms)
USB to RS-485
port converter
Terminating resistor
may be required [
(121 Ohms)
In
Out
In
In
In
Out
Out
Out
PCPC
PC
* Use Belden #9841 or equivalent shielded, twisted-pair
communication cable for RS-485 connections. Ground
one end of the cable shield. Leave the other end of the
cable shield disconnected.
[ Long cables and high communication speeds will require
a terminating resistor. Use 121 ohm resistor X-6058-27.
RS-485 *
Figure 4-4 Serial Connections