Baldor NXE100-1608Dx, Installation Manual

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4-22 Input / Output MN1941
NextMove e 100
(DTE)
9-pin
Computer
COM Port
(DTE)
Serial
RXD 2
TXD 3
GND 5
2 RXD
3 TXD
5 GND
RTS 7
CTS 8
7 RTS
8 CTS
COM
Connect overall shield
to connector backshell.
Figure 22 - RS232 serial port connections
4.5.4 Multidrop using RS485 / RS422
Multidrop systems allow one device to act as a ‘network master’, controlling and interacting with
the other (slave) devices on the network. The network master can be a controller such as
NextMove
e 100, a host application such as Mint WorkBench (or other custom application), or a
programmable logic controller (PLC). RS422 may be used for multi-drop applications as shown
in Figure 23. Four-wire RS485 may be used for single point-to-point applications involving only
one Baldor controller. If firmware is updated over RS485/RS422, it can only be downloaded to
the controller that was chosen in the Select Controller dialog in Mint WorkBench.
Master and final slave are shown
with terminating resistors, T
R
,
typical value 120 Ω .
Network slave
T
R
RXB
DGND
RXA
TXA
TXB
RXB
DGND
RXA
TXA
TXB
RXB
DGND
RXA
TXA
TXB
Twisted pairs
T
R
Connect overall shield
to connector backshell.
Network slave
Network
master
Figure 23 - 4-wire RS422 multi-drop connections
Each transmit/receive (TX/RX) network requires a termination resistor at the final RX connection,
but intermediate devices must not be fitted with termination resistors. An exception is where
repeaters are being used which may correctly contain termination resistors. Termination
resistors are used to match the impedance of the load to the impedance of the transmission line