Eaton M-Max series - Connection Terminals of the Serial Interface and Microswitch S4; (Bus Terminating Resistor); Two-Wire RS485 Connection

Installation
M-Max Series Adjustable Frequency Drive MN04020003E—October 2013 www.eaton.com 45
Serial Interface A-B
The following figure shows the connections of the serial interface and the position of the
micro-switch for the bus termination resistor.
Connection Terminals of the Serial Interface and Microswitch S4
(Bus Terminating Resistor)
The two control signal terminals A and B enable the connection of a shielded RS485
twisted-pair cable.
The bus terminating resistor required at the end of a data cable is integrated in the frequency
inverter and can be connected via microswitch S4.
The network cable must have a bus termination resistor (120 ohms) connected at each
physical end to prevent reflections and the resulting transmission faults.
Two-Wire RS485 Connection
(Slave = M-Max Frequency Inverter)
The parameter definition of the serial interface is described in “Serial Interface
(Modbus RTU)” on Page 131.
12367
8
9
10 25 24
4 5 13 14 15 16 18 20 22 23 26
AI2
DO–GND DI4 DI5 DI6 AO DO+
R13
R14 – R24
+10V AI1 GND 24V DI-C DI1 DI2 DI3 A B R21 R22
LOGIC
– +
AI 1
V mA
AI 2
V mA
RS 485
– Term.
S4 = RS485 (–)
A
B
A
B
PES PES
Slave Master
RS485
Modbus (RTU)
S4
120 ohms
RS485
– Term