The Interface Solution Experts
23
SPA
Site-Programmable Volt &
Milliamp Limit Alarm Trips
EXAMPLE -
Programming an HLPRG Linearization Curve
Following the instructions is step 1 on the preceding
page, a SPA is set up with the following parameters:
• 0-50mA input
(“SEL V/I”, and “SCLE INPT” or “APLY INPT”)
• 0-100% LCD readout
(“PCT” in “CUST FUNC” under “CONF OPTS”, and
000.0 for zero, 100.0 for full scale in “SCLE DSPL“)
Use a graph to show the relationship between INPUT
and DISPLAY:
As shown, plot the INPUT points along the X axis, and
the DISPLAY points along the Y axis.
The “rules” for inputting linearization points are as fol-
lows:
• Xz < Xn < Xn+1 < Xn+2 < ... < Xn+19 < Xf
Where Xz=Input zero, in this case, 0mA;
and Xf=Input full scale, in this case, 50mA;
Xn, Xn+1 through Xn+19 = Input curve
• Yz < Yn < Yn+1 < Yn+2 < ... < Yn+19 < Yf
Where Yz=Display zero, in this case, 0%:
and Yf=Display full scale, in this case, 100%;
Yn, Yn+1 through Yn+19 = Display curve
From steps 2 and 3 of the procedure, 5 points between
0 and 50mA are chosen.
“5” is entered in the “NUMB PNTS” screen. When
SELECT is pressed, the “PNT 01” screen appears.
Pressing select, the arrow buttons are used to enter
the first input point, which, in this example is to be
10mA.
When SELECT is pressed, we are prompted for the
DISPLAY at point 01, which, in this example, we want
to be 20%. Our graph would look like this for point 01:
INPUT
0%,0mA
full
scale
full
scale
50mA
100%
90
80
70
60
40mA
10mA
X
D
ISP
LA
Y
50
40
30
20
10
INPUT
D
ISP
LA
Y
0%,0mA
full
scale
full
scale
50mA
100%
90
80
70
60
50
40mA
10mA
40
30
20
10
