MKS 247D - Figure 4: Pressure Control with an External Controller

Setup Cha
p
ter Two: Installation
28
External Flow Control
Flow control can be accomplished using a set point signal from an external controller only, or
ratioed using an external controller and a pressure transducer.
Figure 4 illustrates pressure control with an external controller; the gas flow into a chamber is
controlled to maintain a constant pressure. This system configuration requires the 247 unit, a
controller, and a pressure transducer. More than four gases may be controlled by adding a
second 247 unit to the system.
Note
Any controller and pressure transducer may be used provided the signal
that enters the 247 unit goes
positive
with increasing flow (correct
polarity). Throughout this manual, the MKS Type 250 Pressure/Flow
Controller and T
yp
e 127/227 Baratron
®
Pressure Transducers are used for
example only.
Figure 4: Pressure Control with an External Controller