Edwards Vacuum Measurement and Control Systems
The Edwards range of instruments offers:
- Measurement over the range 2000 to 10-11 mbar
- Advanced microprocessor based controllers
- Calibration of instruments to UK national standards
Selecting Your Vacuum Gauge
Edwards offers a wide choice of vacuum measurement and control
products - from dial gauges to microprocessor based gauge
controllers. Within each product range, there is a family of models
designed to meet the widest user specification.
The first step in selecting the right gauge to meet your application is
to decide the range of pressures that you want to measure at each of
your measuring points. The chart below indicates the broad pressure
ranges covered by the spectrum of Edwards instruments: use this
chart as a primary guide to the choice of gauge head.
The second step is to establish your requirement for the output of the
pressure measurement. If you simply want an indication that a certain
level of vacuum has been reached (for example, to open a valve or
start a process), then a vacuum switch or Active gauge head alone
may be appropriate. If you want to display the pressure locally, then
a dial gauge may be suitable. If you need the pressure display to be
remote from the measurement point (for example, in a control panel)
then select the TIC Instrument Controller or Active Digital Controller,
depending on the features you require. (You will also need to select
appropriate gauge head(s) to accompany these displays and
controllers.) If your control system (such as a PLC, PC or dedicated
microprocessor controller) needs to know the pressure to make
sequence decisions but you do not need a separate vacuum display,
then you can use an Active gauge head as a stand-alone transducer
connected to an appropriate power supply and control system analog
input.
Thirdly, you need to select a gauge suitable for the process gases
and constructed to withstand exposure to the external environment of
your vacuum system. Consider both whether the gauge will survive in
the process and also whether the process gases will effect the
gauge's measurement. For example, the measurement made by
mechanical gauges (vacuum switches, dial gauges, strain gauges
and capacitance manometers) is not affected by gas composition,
whereas that made by other types of gauges is gas dependent.
Calibration for Different Gases
All of our gauge heads are calibrated for dry nitrogen; the calibration
for dry air is the same. If you use thermal conductivity or ionization
gauges with gases other than nitrogen or air, you may need to apply
a gas correction factor for an accurate indication of your system
pressure. Please contact us if you need more information.
Gauge Head Installation
How you install the gauge head into your vacuum system will affect
the accuracy and reliability of your pressure measurement. For best
performance we recommend that you:
- Connect the gauge head to your vacuum system with a straight,
short branch pipe. This pipe should have an internal diameter no
less than that of the gauge tube itself. Long, narrow or angled
connections can cause a significant measurement error. Note that
the indicated pressure may be higher or lower than the actual
pressure.
- Connect the gauge head as close as possible to the point where
you want to measure the system pressure.
- Orientate the gauge head so that it is vertical, with the connection
to the vacuum system at its base. This prevents debris falling into
the gauge.
The Active Gauge Concept
- Operate from standard power supplies for simple installation
- Gauge type identification signal and common 0-10 V d.c. output
- Cable lengths of up to 100 m for remote operation
- Range of microprocessor based controllers
- The Active gauge range with TIC Instrument Controller give continuous measurement from 2000 mbar to 10-11 mbar
- Low cost analog and digital displays and controllers available
Edwards Active vacuum gauges and controllers give unrivalled
performance, flexibility and ease of use. Traditionally, vacuum
gauges consisted of a sensing element and a separate display/
controller. With Edwards' Active gauges, the functions that are
specific to the gauge type (such as signal conditioning and
specialized power supplies) have been moved from the dedicated
controller and incorporated in the head itself. Now the gauge head
can be used as a stand-alone transducer: it requires only a simple
power supply and it provides a 2 to 10 V output.
Alternatively, you can connect the gauges to a Edwards display or
universal controller: these will accept all gauge types in any
combination for the most flexible solution.
The Active Gauge Range
Active Pirani Gauge
A range of Pirani gauges including linear
measuring from above atmospheric pressure to 10
-4 mbar, with
integral set-point for OEM use.
Active Ion Gauge
A new range of small self-contained Active ion
gauges with a measuring range from 5 x 10
-2 to 5 x 10
-10 Torr. The
gauges incorporate degas, automatic emission current switching,
automatic filament protection, a push button adjustable set point and
status indicating LED.
Active Inverted Magnetron
Operating through the range 10-2 mbar to
10
-9 mbar, with integral set-point for OEM use. A low external
magnetic active field version is available.
Active Wide Range Gauge
A range of gauges measuring from
atmosphere to 10
-9 mbar with a linear output and integral set-point for
OEM use. A low external magnetic field version is available.
Active Thermocouple Gauge
A range of gauges measuring from
atmosphere to 10
-3 mbar, with integral set-point for OEM use and
LED indication of vacuum status.
Active Strain Gauge
A range of strain gauges measuring from 2000
mbar to 1 mbar. This type of gauge is extremely rugged and offers
accurate, gas independent measurement.
Ion Gauge Controller
The Ion Gauge Controller can operate one or
two ion gauge tubes, as well as a high pressure interlocking gauge. It
has a measurement range of 5 x 10
-3 to 2 x 10
-11 mbar, with 3 levels
of emission current and electron bombardment type degas.
Barocel Capacitance Manometers
The Barocel manometers provide high accuracy, high stability, gas
independent pressure measurement making them ideal for a wide
range of industrial process, research and calibration applications.
Their Iconel/Monel construction means that they can also be used
with corrosive and radioactive gases.
- Accuracy 0.15% of reading
- True total pressure measurement, independent of gas species
- Very high corrosion resistance
- Fast response
- Wide range, 4 decade range with single head
- Temperature controlled manometers from 45 to 123 °C
- Excellent stability
- Full scale ranges from 1 mbar to 1000 mbar (0.05 Torr to 1000 Torr)
Active Controllers and Displays
The Edwards Active range of gauges can operate as stand-alone
pressure transducers requiring only a simple power supply and
providing a 2 to 10 V analog output. If you need a complete vacuum
measuring and display system, we also offer a range of controllers
and displays.
Our displays and controllers are designed for maximum flexibility and
ease of use. The range is suitable for bench-top or panel mounting
and options include RS232 interfacing.
TIC Instrument Controller
A compact instrument controller with a
large clear graphical display, an intuitive user interface and serial
communications providing full remote control and data logging
functions for one or more TIC systems via a new Windows
™ based
PC program.
The controller supports, automatically recognizes and controls up to
six gauges from the Edwards range (including IGC and up to three
Barocels), with coverage from 2000 to 6.6 x 10-10 mbar. Low pressure
gauges may be controlled and protected by high pressure gauges
and there are open collector set point outputs. An optional relay box
uses these outputs to control mains changeover relays.
The TIC instrument controller may be either rack or bench mounted
and provides a useful hub for the flexible operation of a wide range of
vacuum system configurations.
Active Digital Controller
The Edwards Active Digital Controller (ADC)
is a compact single gauge controller and display. It features a bright
LED display and simple push-button controls. The ADC automatically
recognizes compatible Edwards gauges, loads the appropriate lookup
table and displays the pressure in commonly used vacuum units.
The ADC is available in standard and enhanced versions. The
standard controller displays the pressure measured by a single active
gauge. The enhanced controller supports two similar gauges - it has
two variable hysteresis set-points which are linked to 48 V d.c. 1 A
changeover relays and two 0-10 V d.c. analog outputs. To aid system
integration, the enhanced controller is provided with an RS232
interface.
When combined with a suitable gauge, such as the Edwards APGX-H
Convection Pirani or Wide Range Gauge (WRG), the ADC represents
a cost effective means of monitoring and controlling process vacuum
in a broad range of applications.
Other Instruments
In addition to the range of Active gauges, Edwards offers a variety of
more traditional vacuum measurement and control products.
Our simple dial gauges provide rugged, local indication of pressures
from atmosphere to 1 mbar and are ideal for vacuum chambers in an
industrial environment. Vacuum switches, with high current ratings,
give a simple method of directly controlling loads without the need for
additional relays or power supplies.
Gauge Calibration Service
All Edwards gauges may either be supplied with a calibration
certificate or re-calibrated by request.
- Provides certificate of calibration traceable to National Standards which meets ISO9000 requirements worldwide
- Service available for both new and returned instruments
- Transducers calibrated separately or with display/controller
As a leading manufacturer of vacuum instruments, Edwards offers an
expert calibration and repair service with 25 years of experience.
Other manufacturers' vacuum instruments including Helium leaks are
also covered. The instruments are calibrated with dry nitrogen; for
calibration with other gases or at specific pressures, please consult
Edwards. The option of calibration figures before and after
adjustments and repairs is also available.
The range of instruments include:
- Active gauges, displays and controllers. Note that Active gauges can be calibrated on their own, with a display or with a controller.
- Capacitance manometers. Note that some types of manometers can be calibrated as stand-alone instruments, with a controller or with a pressure monitor, or example the TIC Instrument Controller.
- Helium quartz leaks for mass spectrometer leak detectors.
Contact Edwards for details.