FUTEK IPM500 (D500) Digital Display - Manual (Page 12)

12
10. READING COORDINATES OF 2 POINTS SCALING METHOD
When the reading coordinates of 2 points scaling method has been selected under SEtuP ,
the four menu items below will appear ahead of all other menu items when the MENU or
key is first pressed from the run mode.
This scaling method applies a straight line fit between two points, which are determined
from actual transducer signals and the desired corresponding meter readings. A low signal,
such as the output of a pressure transducer at zero pressure, and high signal, such as the
output of the same transducer at a known high pressure, are applied to the meter. The
desired corresponding low and high readings are then entered from the front panel. The
meter then applies straight line fit between the high and low calibration points. This scaling
method has the advantage of calibrating the transducer and meter as a system. The actual
voltage or current at either point does not need to be known. This method is ideal for
process and load cell meters, which require zero and span adjustment. It is also available
for DC or AC meters. It is not available with thermocouple or RTD meters.
The programming example below is for a process meter used with a 4-20 mA pressure
transducer for 0 to 100 psi. Decimal points are set separately using the dEC.Pt menu.
Press Menu Select
Key Press Digit Select
Key Press Value Select
Key
Lo In
Apply low signal input
(e.g., transducer output for 0
psi).
_ 40.21
Press to display
reading at low signal input
(e.g., 4.021 mA).
_ 40.21
Press to store low
reading.
Hi In Apply high signal input
(e.g., transducer output for
known 100.00 psi source). 200.94
Press to display
reading at high signal input
(e.g., 20.094 mA).
200.94 Press to store high
reading.
Lo rd
Mode to enter desired low
reading (e.g., 0.00).
0 00.00 000.00 000.00
000.00 000.00 Select digit
to flash.
10 0.00 Select -9 thru 9 for
flashing first digit,
0
thru
9
for
other flashing digits.
Hi rd
Mode to enter desired high
reading (e.g., 100.00).
0
00.00 000.00 000.00
000.00 000.00 Select digit
to flash.
100.00
Select
-9
thru
9
for
flashing first digit, 0 thru 9 for
other flashing digits.