User manual for meter with U/I input PD72S
Normalized measurement I
n
(for 0-20 mA range)
Input current [mA]
Figure. 10.4 Example of user defined characteristic
10.2. EXAMPLES OF CALCULATIONS
Example 1: Selection of the permissible input range
(“4-20” mode)
If in “
4-20
” mode the user sets
“Lo r”
= 20.0 % and
“Hi r”
= 10.0 %, then permissible input
currents range will be equal: 3.2 mA ÷ 22 mA. Lower border of the range is the result of
calculations: 4 mA - 4 mA × 20 %, and the higher: 20 mA + 20 mA × 10 %.
Example 2: The normalized I
n
result calculation
Let the input mode = 4-20 mA. The normalized I
n
result is calculated accordingly to the
expression on page 34, so if I
in
= 10 mA then 10 mA - 4 mA = 6 mA, and this result should be
divided by the width of input range (16 mA). Finally the normalized result: I
n
= 6/16 = 0.375.
In case when input current exceeds nominal measurement range, calculations are similar. For
example if input current is equal 2.5 mA then I
n
= (2.5 - 4)/16
≅
-0.0938, and if input current is
equal 20.5 mA then I
n
= (20.5 - 4)/16
≅
1.0313.
Example 3: The linear characteristic
Let the input mode = 4-20 mA, and parameters
“Lo C”
and
“Hi C”
equal to -300 and 1200
respectively. The calculations will be done for there different input currents from example 2.
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