SPA
24
The Interface Solution Experts
Site-Programmable Volt &
Milliamp Limit Alarm Trips
Following the menu prompts for each of the five points,
the graph would look like this:
I NPUT
0%,0mA
full
scale
full
scale
50mA
100%
90
80
70
60
40mA
10mA
X
X
X
X
X
X
(10mA, 20%)
(20mA, 40%)
(25mA, 50%)
(30mA, 60%)
(40mA, 80%)
D
ISP
LA
Y
50
40
30
20
10
Notice that the 5 points create 4 segments. The end
segments, shown by the dashed lines are defined by
the coordinates of the input scale and the display scale
and the adjacent curve points.
Any inputs that fall outside the input scale are defined
by the same slope and offset of the dashed segments
in the graph.
A 20-point curve can therefore define 21 segments.
If more points are to be added...
the SPA menu automaticalles takes the user to the
point that has not yet been defined. The user cannot
exit the curve programming until all points are defined.
NOTES:
If INPUT SCALING (X-axis) is changed, during
SPA operation, to fall within the curve values
(violation of the “rules” on the preceding page),
a TABLE ERROR message will be returned.
If the DISPLAY SCALING (Y-axis) is changed,
the curve coordinates automatically change to
proportionally fall within the new display scale.
If the display scaling in our example were changed, the
following would be implemented automatically by the
unit:
INPUT INITIAL
0-750
500-1000
DISPLAY UNITS UNITS
SCALE
10mA 20%
150
600
20mA 40%
300
700
30mA 60%
450
800
40mA 80%
600
900
NOTE:
When a TABLE ERROR occurs, change the
INPUT SCALE to “follow the rules”.
The change will not be processed by the SPA
until the Configuration menu is exited, or until
power is recycled.
