HPP-4
10
September 1999
Spring
Range
Green (20-2592)
1-6
Silver (25-1038)
2-11
Blue (25-1036)
4-20
Red (25-1037)
8-30
Table 1
: Adjustable Bias Springs
HPP-4 Positioner
Range Adjustment
Range Adjustment
Note:
There will be some interaction between
range and bias adjustments. It may therefore
be necessary to readjust the bias and re-check
the range after completing the following steps.
The range, or the amount of travel be-
tween the lower and upper limits of the
input signal, is set with the
range
spring
.
This range will typically be 12
psi for a 3-15 psi system or 24 psi for a
6-30 psi system. The limits of the range
can be defined as the initial point at
which the instrument signal
to the
HPP-4
starts valve
movement until the end of
the valve stroke and full
pressure differential across
the cylinder output gauges.
1.
After setting the bias for
the start of the valve travel,
continue increasing the in-
strument signal until the
valve strokes is completed AND the
cylinder output gauges show full
power gas pressure differential.
2.
Be sure not to overshoot at this
point as any signal level above this
upper limit will show the same read-
ing on the cylinder gauges. This
point is the highest end of the range
and the value may not necessarily
be equal to the desired upper range
value.
Note: For intermediate ranges, use the next
size range spring.
Stroke (Part Number)
4
6
8
12
6
01-6288 01-6287 01-6287 01-6801
12
25-1151 25-1152 25-1153 25-1154
18
25-1599 25-1600 25-1601 25-1602
24
25-1218 25-1219 25-1220 25-1221
Spring Range
(psi)
Table 2
: Range Spring Configurations
