3-1
Section 3 Operation
Models SLA5810/20 and SLAMf10/20
Installation and Operation Manual
X-PR-SLA5800-SLAMf-Series-RevB-PC-eng
Part Number: 541B198AAG
January, 2017
3-1 Overview
This section contains the following information:
• Theory of Operation (Pressure Controllers)
• Features (Pressure Controllers)
3-2 Theory of Operation for Pressure Control
The pressure is measured via a stainless steel diaphragm that
mechanically transmits a resistance change to a Wheatstone bridge
configuration. The change in the bridge resistance is proportional to
pressure. An electronic amplifier provides output to the control circuit as
well as the electrical output signal.
In addition to the pressure transducer the Models SLA5810/20 and
SLAMf10/20 have an integral control valve and control circuitry. A
difference between the pressure and setpoint signals will cause the
electronics to modulate the control valve to maintain the desired pressure.
A system block diagram is shown in Figure 3-1.
The integration of pressure transducer, control electronics and control
valve into one unit results in a compact size. The mounting dimensions are
comparable to a mass flow controller. Refer to Figures 1-5 to 1-10.
The “upstream pressure regulation mode” shown in Figure 1-1 places the
pressure controller at the outlet of the pressure vessel. The pressure in the
process upstream of the controller will be constant independent of
downstream variation. Pressure measurement and control takes place at
the outlet side of the pressure vessel.
3-3 Features
Note: All digital pressure controllers are configured at the factory according to
customer order and do not require adjustment. Not all features are available
on all instruments.
The SLA5810/20 and SLAMF10/20 are full-featured digital pressure
controllers. The digital pressure controller performs much like a traditional
analog pressure controller, but with improved accuracy, step response and
valve control. The analog interface matches that of Brooks' popular analog
pressure controllers so it can be retrofitted into tools using analog pressure
controllers. Other versions of the digital pressure controller can provide a
variety of digital protocols such as Profibus, DeviceNet & RS485.
