Precision Digital Corporation PD6928, Instruction Manual

Page: 23 / 80

PD6928 Loop-Powered Flow Rate/Totalizer Instruction Manual
23
Wiring Diagrams
Current Loop (4-20 mA) Connections
Signal connections are made to a three-terminal
connector. See
Connectors Labeling on page 21 . The
following figures show a 4-20 mA current loop
connected to the meter.
Figure 8 shows the
connection without the backlight and Figure 9 shows
the connection with the backlight (the backlight can be
disabled/enabled in the
SYSTEM
menu, if connected).
The meter and the backlight are powered by the
4-20 mA current loop.
There are no switches or jumpers to set up for the
input. Setup and programming are performed through
the CapTouch buttons or PC-based software.
Figure 8. 4-20 mA Input Connection without Backlight
Figure 9. 4-20 mA Input Connection with Backlight
The current input is protected against current
overload up to 1 amp. The display may or may not
show a fault condition depending on the nature of the
overload.
Digital Input Connections
A digital input is standard on the meter. This digital
input is connected with a normally open contact
across DI+ and DI-, or with an active low signal
applied to DI+ and DI-.
Figure 10. Digital Input Connections
4-20 mA Output Connections
Connections for the 4-20 mA transmitter output are
made to the connector terminals labeled 4-20 mA
Output on
Figure 6 , page 22 . The 4-20 mA output
must be powered from an external power supply.
Figure 11. 4-20 mA Output Connections
Solid-State Relay Connections
Relay connections are made to two-terminal
connectors, as shown on
Figure 5 , page 21 . Each
relay’s C terminal is common only to the normally
open (NO) contact of the corresponding relay.
Figure 12. Solid-State Relay Connections
- - +
BL mA
4-20 mA
Transmitter
+ -
Power
Supply
+
-
- - +
BL mA
4-20 mA
Transmitter
+ -
Power
Supply
+
-
- +
DI
- +
Device with
4-20 mA
Input
- +
Power
Supply
+ -
C NO
C NO
Load
Load
Power
Relay 1
Relay 2