The Interface Solution Experts
21
SPA
Site-Programmable Volt &
Milliamp Limit Alarm Trips
Programming SPA Linearization —
Entering Segment Endpoints
in Custom Mode
From this menu the user can program up to 20
linearization points into non-volatile HLPRG SPA
memory. This capability works exclusively with the
unit’s Custom Mode to make the SPA display linear
with respect to its scaled input. When enabled (in the
“CONF OPTS” menu, discussed earlier), the SPA’s
Custom Mode sets the unit to display the linearized
input value in the user-set engineering units.
As mentioned, the “ENTR CURV” menu is active only
when the SPA’s “CUST FUNC” Custom Mode selection
has been made in the Configure Options menu.
IMPORTANT:
Input zero and full scale as well as display
zero and full scale must be programmed prior
to programming the linearization curve.
The procedure consists of defining the number of
points that are to constitute the linearization curve,
then specifying first the input, then its corresponding
display value at each point. Figure 13 shows the
menu.
1. Make sure that the zero and full scale values
have been entered into memory for:
• Input scaling (“smart” scaling) or input
capturing (bench scaling)
• Display scaling
• Analog Output (if present)
2. From the “ENTR CURV” point of the main,
HLPRG SPA menu, press SELECT.
3. Press SELECT from the next screen, “NUMB
PNTS”, to bring up a screen for entering the
number of points to be used in the linearization
curve.
or
Press the down arrow button to bring up the
“ENTR PNT” screen. Pressing SELECT
will bring up a screen allowing you to enter
a particular point that is to be changed,
assuming that the curve has been entered
previously.
The “rules” for entering points are:
• 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
NOTE:
The endpoints of the curve must
fall within a range defined by the zero and full
scale values for both the input and the display
(see the graph, below).
INPUT
D
ISP
LA
Y
0
FULL
SCALE
ALL POINTS MUST FALL BETWEEN
ZERO AND FULL SCALE OF BOTH
DISPLAY AND INPUT SCALING.
FULL
SCALE
4. When the display shows the point number that
is to be programmed, press SELECT
.
