Control Techniques UD70 Installation Manual page 10

2.5.1 4 Wire RS485 Network
The diagram below shows the connections required for a 4 wire RS485 network,
using a master controller with an RS485 port. The UD70 and MD29 can be
configured to act as master controllers, but this requires DPL programming to
control the network.
M a ste r
0 V
Tx B
Tx A
R x B
R x A
An RS232-to-RS485 converter is required to allow a standard PC serial port to
communicate with a 4 wire RS485 network.
2.5.2 2 Wire RS485 Network
The diagram below shows the connections required for a 2 wire RS485 network,
using a master controller with an RS485 port. The UD70 and MD29 can be
configured to act as master controllers, but this requires DPL programming to
control the network.
Master
0V
TxB
TxA
RxB
RxA
An RS232-to-RS485 converter with "intelligent transceiver switching" (also known
as "magic" RS485 converters) is required to allow a standard PC serial port to
communicate with a 2 wire RS485 network. An example of a "magic" converter is
the MA485F converter from Amplicon.
A "magic" converter is not required is the master contoller has an RTS control
NOTE
output. This output is enabled when the master is transmitting, and disabled
when the master is not transmitting. Control Techniques software packages
(UniSoft, MentorSoft and SystemWise) do NOT switch the RTS line.
7
U D 7 0, M D 2 9,
U n id riv e, M e nto r II
0V T x B
1
12 0 Ω 0.2 5 W
te rm in atio n re sisto rs
0V
120Ω 0.25W
termination resistor
www.controltechniques.com
S la ve
Tx A R xB R x A
2 6 3 7
Slave
UD70, MD29,
Unidrive
TxB TxA RxB RxA
1 2 6 3 7
S la ve
U D 7 0, M D 2 9,
U n idriv e, M en to r II
0 V T x B T xA R x B
1 2 6 3
Slave
Commander SE
0V TxRxB TxRxA
3 7
UD70/MD29 Installation Guide
Issue Number: 3
R xA
7
2