TP-6833 2/16
38 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:
Modbus
r
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
PC
PC
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
