DL205 Analog Manual, 7th Edition Rev. D
14-15
Chapter 14: F2-4AD2DA 4-Ch. In / 2-Ch. Out Analog Combination
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A
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D
Scaling the Input Data
Most applications usually require measure-
ments in engineering units, which provide
more meaningful data. This is accomplished
by using the conversion formula shown.
Adjustments to the formula may be needed
depending on the scale chosen for the engi-
neering units.
For example, if pressure (PSI) is to be
measured with a scale of 0.0–99.9, a multi-
plication factor of 10 would be needed in
order to imply a decimal place when the
value is used in the user program.
The following rung of logic is an example showing how the program can be written to perform
the engineering unit conversion. This example assumes the data is in BCD format before being
loaded into the appropriate V-memory locations using instructions that apply to the CPU
module being used.
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Units = A H–L
4095
U = Engineering Units
A = Analog Value (0–4095)
H = High limit of the engineering
unit range
L = Low limit of the engineering
unit range
LD
V2000
SP1
MUL
K1000
DIV
K4095
Load channel 1 data to the accumulator.
Multiply the accumulator by 1000 (to start the conversion).
Divide the accumulator by 4095.
OUT
V2010
Store the result in V2010.
Note, this example uses SP1, which is always on. You
could also use an X, C, etc. permissive contact.
Units = A H–L
4095
Units = 2024 100–0
4095
Units = 49
Units = 10A H–L
4095
Units = 20240 100–0
4095
Units = 494
Analog Value of 2024, slightly less than half scale, should yield 49.4 PSI.
Example without multiplier Example with multiplier
Summary of Contents for DL205
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