ProtEX-MAX PD8-7000 Explosion-Proof Temperature Meter Instruction Manual
16
Connections for Averaging RTD Sensors
To obtain the average temperature from 2 to 10 RTD sensors, connect all the sensors in parallel and
select the number of sensors in the
RTD Total
(
rtdtot
) menu. See the Advanced Features Menu on
Figure 8. Average Temperature RTD Input Connections
Serial Communications Connections
The ProtEX-MAX has a 5 position terminal block for connecting RS-485 serial devices.
Figure 9 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 9: 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 10. Three-Wire RS485 Connection
RTD1
SIGNAL
EXC
T+
COM
1
2
3
RTD
TYPE
TC
100
RANGE
10
M-LINK
1 2
3
4 5 6 7 8
RTD2
RTD3
F4 COM
DI
DI DO DO
TX
RX
1 2 3 4 5
1 2
