ProtEX PD8-6080/PD8-6081 Explosion-Proof Modbus
®
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17
Serial Communications Connections
The ProtEX-MAX has a 5 position terminal block for connecting RS-485 serial devices.
Figure 5 details the wiring connections from the ProtEX-MAX to an RS-485 serial converter (such as the
PDA7485 or PDA8485) for a four-wire network.
ProtEX-MAX to RS-485
Serial Converter Connections
RS-485 Serial
Converter
ProtEX-MAX RS-
485 Connections
DO
DI
DO
DI
DI
DO
DI
DO
Figure 5: ProtEX-MAX Connections to a Serial Converter
The ProtEX-MAX has three diagnostic LEDs: a Power (P) LED to show when the module is powered
properly, a Transmit Data (TX) LED to show when the module is being transmitted to by the PC side, and
a Receive Data (RX) LED to show when the module is sending data to a receiving device.
The following diagrams detail how to connect the RS-485 serial communications from the ProtEX-MAX to
a RS-485/RS-232 serial converter (PDA7485) in four wire and two wire configurations.
Three Wire Connections
In order to wire the 5 pins for use as a 3-wire half-duplex RS-485 connection, it is necessary to create a
jumper connection between DI
– DO and DI- – DO- as shown below.
Figure 6. Three-Wire RS485 Connection
F4
COM
DI
DI
DO
DO
T X
RX
1 2 3 4 5
1 2
