Helios PD2-6100 Strain Gauge, Load Cell, and mV Meter
Instruction Manual
21
RS-485 Converter Connections
below details the wiring connections from
the RS-485 connector to an RS-485 serial converter
(such as the PDA7485-I or PDA8485-I) for a five-wire
network.
RS-485 Connector to RS-485
Serial Converter Connections
RS-485 Connector
RS-485 to USB or
RS-232 Converter
DO
DI
DO
DI
DI
DO
DI
DO
Figure 25. Connections for RS-485 Connector to
Serial Converter
Three-Wire Connection
In order to wire the five pins for use as a three-wire
half-duplex RS-485 connection, it is necessary to
create a jumper connection between DI to DO and /DI
to /DO- as shown below.
Figure 26. Three-Wire RS-485 Connection
Digital I/O Connections
Digital inputs and outputs are provided in order to
expand the functionality of the meter. Digital input
connections are made via a push button or switch to
the appropriate digital input terminal and the +5 VDC
terminal. Digital output connections are made by
wiring from the appropriate digital output terminal to
the ground terminal.
Figure 27. Digital Input and Output Connections
F4 Digital Input Connections
A digital input, F4, is standard on the meter. This
digital input should be connected with a normally
open contact across F4 and COM, or with an active
low signal applied to F4. It can be used to operate the
tare function, for remote operation of front-panel
buttons, to acknowledge/reset relays, or to reset
max/min values. See
capabilities.
Figure 28. F4 Digital Input Connections
4-20 mA Output Connections
Connections for the 4-20 mA transmitter output are
made to the connector terminals labeled mA OUT.
The 4-20 mA output may be powered internally or
from an external power supply.
Figure 29. 4-20 mA Output Connections
Analog Output Power Supply
If the analog output is not using the 24 VDC supply to
power the output loop, it can be used for other things.
The I+ Terminal is the +24 V and the R terminal is the
return.
Figure 30. Analog Output Supply Powering Other
Devices
__ __
DI
DI DO DO
O1 O2 O3 O4 G
I
1
I
2
I
3
I
4
+5
Ground
5 VDC
4-20 mA Input
Remote Display, PLC,
Chart Recorder, Etc.
-
+
R
I-
I+
1
3
2
RELAY1
mA OUT
24 V
12-35 VDC
Power
Supply
+
4-20 mA
Input Meter
-
+
R
I-
I+
1
3
2
RELAY1
3
2
1
-
24 V
mA OUT
Internal Power Supply
and Analog Output
3
2
1
Active Output Loop
Passive Output Loop
R
I-
I+
1
3
2
24 VDC
Powered
Device
24 V
+
-
