B6
Parker Hannifin Corporation
Pneumatic Division
Richland, Michigan
www.parker.com/pneumatics
A
B
C
D
E
F
G
H
J
K
L
M
Catalog 0700P-5/USA
Features & Benefits
Why Proportional Technology ?
The Difference Between Open or
Closed Circuit Control
Standard pressure regulators go a long way towards
meeting customers needs. In most cases these
regulators work well in general pneumatic and
automation applications. However, sometimes the
application calls for more precise pressure control.
The effects of time, cycling, input, back pressure or
pressure and flow variation can all cause inconsistencies
in pneumatic systems. Proportional Regulators are
designed to eliminate those inconsistencies.
Open Control Circuit
In a normal pressure regulated control system, the inlet
pressure (p1) is converted into the output pressure
(p2) by the regulator. The set pressure (set value) is
usually manually set by adjusting the control knob and
in normal circumstances the regulator maintains the
output pressure (actual value).
No facility for monitoring the output pressure is
provided and there is consequently no way of checking
that the set value and the actual value are the same.
Also, no account is taken of external influences such as
air consumption by the system, which can drastically
alter the actual value.
Typical Application in Automotive Body in
White Welding Pressure Control
Closed Loop Control Circuit
The input signal (Electronic Control Signal) is
converted into the output value (P2 Output Pressure).
This output value is continuously measured and
compared with the input signal. If they are different, the
unit adjusts the output value to correspond to the set
value, to close the loop.
Proportional Pressure Regulators
The Proportional Regulators provide all the advantages
of a closed circuit regulated system. When a set value
is defined via the input signal (e.g. 0-10 V), the pressure
regulator sets the corresponding output pressure (e.g.
0-150 PSI/0-10 bar). At the same time the integrated
pressure sensor measures the actual pressure at the
unit’s outlet (actual value).
If the electronic regulation system finds that the actual
value has deviated from the set value, it immediately
corrects the actual value. This is a continuous process
ensuring fast, accurate pressure regulation.
“P3HPA” / “P3KNA” Series
Electronic Proportional Regulators
