Modbus; To Set Up The Rtu Open For Modbus - Carrier RTU Open v5 Integration Manual


If the network has greater than 32 devices or exceeds 2,000 feet, a Repeater should be installed.

If a controller begins or ends a network segment, a terminating resistor may be needed.
Software settings defined through the Equipment Touch device. To confirm settings, obtain a Modstat of the
device. On the Equipment Touch, click the link to the Modstat.

Modbus

To set up the RTU Open for Modbus

Refer to Appendix C (page 56) for the Modbus Protocol Implementation Conformance Statement (PICS).
Turn off the RTU Open's power.
1
NOTE Changes made to the switches when the controller is on will not take effect until the power is cycled!
Using the rotary switches, set a unique Modbus slave address for the RTU Open. Set the MSB (SW1) switch to
2
the tens digit of the address, and set the LSB (SW2) switch to the ones digit. Valid Modbus slave addresses
are 01-99.
EXAMPLE To set the controller's Modbus slave address to 01, point the arrow on the MSB (SW1) switch to 0
and the arrow on the LSB (SW2) switch to 1.
M S B
SW1
0
10's
Set the SW3 DIP switches 1 and 2 for the appropriate communications speed (9600, 19.2k, 38.4k, or 76.8k
3
bps).
NOTE Use the same baud rate and communication settings for all controllers on the network segment. The
RTU Open is fixed at 8 data bits, No Parity, and 1 Stop bit for this protocol's communications.
Baud DIP switch settings
Baud rate
9,600 bps
19.2 kbps
38.4 kbps
76.8 kbps
RTU Open v5
Integration Guide
SW2
LS B
0
1's
2
Off
On
Off
On
1
Off
Off
On
On
11
Communications wiring
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