Pneumatic Control Manual
717.1
Comparators, Cumulators, and Relays Section
Product Bulletin
C-9500
Issue Date
1285
© 1985 Johnson Controls, Inc.
1
Part No. 24-1233-18, Rev. B
Code No. LIT-7171445
C-9500
Two-Position Pilot Cumulator
The C-9500 Two-Position Pilot
Cumulator is designed to switch
its output from zero to full input
pressure at a preselected
pressure. It provides
two-position output from a
proportional input signal.
The C-9500 features an
adjustable set point and
differential. The set point is
adjustable from 4 to 20 PSIG
(28 to 140 kPa) and is factory set
at approximately 9 PSIG
(63 kPa); the differential is
adjustable from 1 to 7.5 PSI
(7 to 52.5 kPa) below the set
point and is factory set at
approximately 1 PSI (7 kPa).
When the input pressure is below
the set point, the output will be
zero. When the input reaches
the set point, the output will
switch and become equal to the
input. Beyond the set point, the
output pressure will increase at a
1 to 1 ratio with a rising input
pressure.
Operation
In a typical application (see
Fig. 2), the input of the C-9500 is
connected to a proportional
controller and the output is
connected directly to the valve
actuator. As the controller
output pressure increases, the
output of the C-9500 remains at
zero until the controller output
pressure reaches the set point
of the C-9500. At that pressure,
the C-9500 snaps open and the
input is delivered to the output,
closing the valve completely.
After the controller completes its
cycle, its output pressure
decreases and the output of the
C-9500 also decreases. As the
controller output pressure
reaches 8 PSIG (56 kPa), the
pilot chamber of the C-9500
snaps closed and the output
goes to zero, opening the valve.
Note: The signal to the
C-9500 must be a high volume
signal; a low volume signal or
a situation where the output
line is very long may cause
the C-9500 to cycle. This
device is specifically designed
for direct mounting on the
controlled device (as
described in the installation
section) to keep its output
working capacity at a
minimum.
Application and Drawing
Identification
Fig. 1: C-9500 Two-Position
Pilot Cumulator
Specifications
