Rockwell Automation 1769-SM2 Compact I/O DSI/Modbus Communication Module - Manual (Page 17)

Getting Started 1-5
In Multi-Drive mode, any channel can be configured for “RTU Master”
operation (
Figure 1.4 ). This enables connection of up to 31 RTU Slave
devices, such as PowerFlex 7-Class drives with 20-COMM-H RS485
HVAC adapters.
Figure 1.4 Multi-Drive Mode and Modbus RTU Master Mode Wiring Example
120 ohm, ¼ Watt
Terminating Resistor
AK-U0-RJ45-TB2P
Terminal Block
Connectors
AK-U0-RJ45-TB2P
Terminal Block
Connectors
MODULE CH1 CH2 CH3
C H 1
C H 2
C H 3
1769-SM2
Module
CH3 - Modbus RTU Master Mode (up to 31 Devices)
CH1 - Multi-Drive Mode (up to 5 PowerFlex 4-Class Drives)
CH2 - Multi-Drive Mode (up to 5 PowerFlex 4-Class Drives)
120 ohm, ¼ Watt
Terminating Resistor
120 ohm, ¼ Watt
Terminating Resistor
CH1
CH2
CH3
User-Supplied Wire (recommend
Belden No. 3105A or equivalent)
User-Supplied Wire (recommend
Belden No. 3105A or equivalent)
User-Supplied Wire (recommend
Belden No. 3105A or equivalent)
Ground Wire Connection
(for network
communication
cable shielding)
Earth Ground
Connection
PowerFlex 7-Class Drives
with 20-COMM-H RS485 HVAC
Communication Adapters Generic
Modbus RTU
Device
. . .
Wiring Tip:
The 1769-SM2 has an
integral terminating
resistor for each channel.
Thus, it is only necessary
to connect a terminating
resistor to the RJ45
terminal block at the last
drive on each channel.