Precision Digital PD6820 - Manual (Page 14)

PD6820 Loop-Powered Process Meter Instruction Manual
14
Input Signal & Backlight Connections
Signal and backlight connections are made to a four-terminal connector mounted in
the base of the enclosure. For installations without backlight, only the two signal
terminals are connected. The 4-20 mA input with no backlight has a maximum
voltage drop of 3 V and is wired as shown in Figure 2. The loop-powered backlight
configuration requires a total maximum voltage drop of 6 V. The backlight is
recommended for dim lighting conditions and is enabled when wired as shown in
Figure 3 or Figure 4.
4-20 mA
Transmitter
Power
Supply
SAFE-TOUCH
BUTTONS
BACKLIGHT
POWER
UNLOCK LOCK LOOP 9-36 VDC
+ - + -
SIGNAL BACKLIGHT
+ - + -
OUTPUT RESET
Figure 2. Input Connections without Backlight
4-20 mA
Transmitter
Power
Supply
SAFE-TOUCH
BUTTONS
BACKLIGHT
POWER
UNLOCK LOCK LOOP 9-36 VDC
+ - + -
SIGNAL BACKLIGHT
Slide Switch to
LOOP
+ - + -
OUTPUT RESET
Figure 3. Input Connections with Loop-Powered Backlight