User guide

LI25 Series Loop-Powered Meters Instruction Manual
4-20 mA Input Connections
Input connections are made to a four-terminal connector labeled
S+|S-|B+|B-. The loop-powered backlight is an optional configuration and
requires a total maximum voltage drop of 5.7 V. The backlight is
recommended for dim lighting conditions and is enabled when wired as
shown in Figure 3. It may be bypassed if installed in bright lighting
conditions to reduce the maximum voltage drop to 2.0 V as shown in
Figure 4.
S
+
S
- B+ B-
4-20 mA
Transmitter
Power
Supply
Figure 3. Input Connections with Backlight
S
+
S
- B+ B-
4-20 mA
Transmitter
Power
Supply
Figure 4. Input Connections without Backlight
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