CAL Controls 3300 - Linear Input Calibration Steps; Calculating Calibration Settings

Advanced Settings
3 Allocate the output devices at function SP1.D
as described in
SET-UP , enter the configuration
into the memory and proceed as follows:
Calculate the values for the controller settings for
HI.SC and SPAN using the example below
as a guide:
4 to 7mV input from transducer is required to
display 0 - 110 units
Chose Linear Range Lin4 4-20mV = 0 to 1000 units.
HI.SC = Nominal Signal Span
x required span
actual signal span
(20-4)
x (110-0) = 587
(7-4)
SPAN = (
hi.SC - nominal scale span) x hi.SC
Nominal Scale Span
(587-1000) x 587
= -242
1000
These settings should provide the correct scaling adjustment,
but a value for ZERO may need to be established by
applying the lowest and highest mV input signal and
recording the display offset. Check that this is the same at
each end, and enter this plus or minus value as a ZERO
adjustment. Should there be a difference between the two
readings, a further adjustment of the SPAN setting can
be made.
1 Power up the controller, and in response to the
prompt INPT
nonE select an appropriate
Linear Range from the table below.
Ensure that the Nominal Signal Span chosen is wider
than the transducer’s actual signal span, and the
Nominal Scale is wider than the full scale of the
engineering units to be displayed.
2 Select UNIT , then select the process unit,
°C ,
°F , Bar , PSI , Ph , or rh . If the required unit is not
shown select
Set .
Linear
Range
Lin 1
Lin 2
Lin 3
Lin 4
Lin 5
Nom. Signal
Span
0–20 mV
4–20 mV
0–20 mV
4–20 mV
0–20 mV
Nom. Scale
Span
0 – 100
0 – 100
0 –1000
0 – 1000
0 – 2000
Max. Scale
Settings
0 – 400
-25 to 400
0 to 3000
-250 to 3000
0 to 3000
26
1 2 3 4 5 6 7 8
LN
5Vdc
15mA
+
–
+
–
9 10 11 12 13 14 15 16
Supply
1 ohm
4–20 mA
from transducer
Outputs
Linear Input Calibration (continued)