Control Techniques M'Ax 403 User Manual page 19

EIA485
TX
interface
TX\
0V
RX
RX\
7 6 12
TX\
Figure 2-8 EIA485 link connecting a number of devices
Connect a line-termination resistor between the rx and rx\ lines only at
the last Drive or device on the serial link (ie. the unit furthest from the
host). The value of the resistor must be equal to the characteristic
impedance of the cable.
Do not fit resistors to other units in the system, otherwise excessive
signal loss will occur.
Field gateway
Any
TX
fieldbus
TX\
0V
RX
RX\
Field gateway
Figure 2-9 Modbus RTU
M'Ax User Guide
Issue Number: 4
14 13 7 6 12
TX RX\ RX TX\
0V COMMON
MC/EIA485
7 6 12 14 13
TX\ TX RX\ RX
0V COMMON
MC/EIA485
14 13 7 6 12
TX RX\ RX TX\
0V COMMON
MC/EIA485
Fieldbus
For multi-Drive systems, the current trend is to use fieldbus
communications to connect all the components of the drive system
together. This reduces field wiring, and allows comprehensive control
and diagnostic information to be transferred from device to device. The
M'Ax Drives have an RS485 port that can be configured to operate
using the Modbus RTU protocol. Modbus is a multi-drop protocol so that
multiple Drives can be connected on the same network. To connect a
M'Ax Drive to a fieldbus system a gateway device can be used to
convert from one network system to another, such as Devicenet to
Modbus.
Control Techniques Drive Centres can supply a range of gateway
options to suit most common fieldbuses.
7 6 12 14 13
TX\ TX RX\ RX
0V COMMON
MC/EIA485
*
14 13
TX RX\ RX
0V COMMON
MC/EIA485
7 6 12 14 13
TX\ TX RX\ RX
0V COMMON
MC/EIA485
To
other
Modbus
device
13