Loop Powered Indicator Page 10 Appendix B
If the selected BU is Custom, no other units are affected.
Upon power-up the MPU makes all display segment elements active for 5 seconds; this
allows a visual check for non-functioning elements. After 5 seconds the LPI begins dis-
playing values in the unit (BU) that was active before power-down.
2.3.2 Accuracy and Decimal Point Settings
The LPI has a stated accuracy of ± 0.1% of the milliampere span, equivalent to ± 0.016 mA
at reference conditions. The accuracy is further affected by temperature at a rate of ± 0.01%
per °C. When units other than mA or % are used the LPI automatically positions the
displayed decimal point to give the best reading consistent with the stated accuracy but not
a reading that is misleading. Decimal point movement in the display thus depends on the
configured span as follows.
Table 2-1 - Span versus Decimal Point Position
SPAN ± .1% Value Display Reading
10000 Up ± 10 10000 Up 1.0 to 19999
1000 Up ± 1 1000 Up 1.0 to 9999
100 Up ± .1 100 Up 0.1 to 1999.9
10 Up ± .01 10 Up 0.01 to 199.9
1 Up ± .001 1 Up 0.001 to 19.999
.1 Up ± .0001 .1 Up 0.0001 to 1.9999
As indicated in Table 2-1, the display will suppress leading zeros but always show one zero
to the left of the decimal point where possible.
2.3.3 Displaying Current Using the LPI
In Run mode the LPI converts the flowing current into a value displayed in the selected
Base Unit (BU). The Mode (left-hand) button is used to temporarily display the current in
one of the other units; the Select (right-hand) button has no effect. When the Mode button
is pressed the next available unit will appear for 10 seconds, after which the display will
revert to displaying the selected BU. The number of units available for viewing depends on
the selected BU as follows.
Table 2-2 - Units Temporarily Displayed versus Selected Base Unit (BU)
Base Unit Available Units
mA mA, %
%mA, %
psi mA, %, psi, inH2O, bar, kg/cm2
InH2O mA, %, psi, inH2O, bar, kg/cm2 *
Bar mA, %, psi, inH2O, bar, kg/cm2
kg/cm2 mA, %, psi, inH2O, bar, kg/cm2
Celsius mA, %, Celsius, Fahrenheit
Fahrenheit mA, %, Celsius, Fahrenheit
Custom mA, %
* Conversion into inches of water (inH2O) from pounds per square inch (psi) uses the
constant 27.7066 inH2O per psi at 60° F.
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