Edwards AIGX-D-NW25 User manual

D048-60-880
Issue E Original
Instruction Manual
Active Ion Gauge
Description Item
Number
AIGX - D - NW25 D048-60-000
AIGX - D - DN16CF D048-61-000
AIGX - D - DN40CF D048-02-000

This product has been manufactured under a quality management system certified to ISO 9001:2008
Declaration of Conformity
We, Edwards Limited,
Crawley Business Quarter,
Manor Royal,
Crawley,
West Sussex, RH10 9LW, UK
declare under our sole responsibility, as manufacturer and person within the EU authorised
to assemble the technical file, that the product(s)
Active Ion Gauge
AIGX-D-NW25 D048-60-000
AIGX-D-DN16CF D048-61-000
AIGX-D-DN40CF D048-62-000
to which this declaration relates is in conformity with the following standard(s) or other
normative document(s)
EN61010-1: 2010 Safety Requirements for Electrical Equipment for Measurement,
Control and Laboratory Use. General Requirements
EN61326-2-3: 2013 Electrical equipment for measurement, control and laboratory
(Class B Emissions, Use. EMC requirements. Particular requirements. Test
Industrial Immunity) configuration, operational conditions and performance criteria for
transducers with integrated or remote signal conditioning
EN50581:2012 Technical Documentation for the Assessment of Electrical and
Electronic Products with respect to the Restriction of Hazardous
Substances
and fulfils all the relevant provisions of
2014/30/EU Electromagnetic Compatibility (EMC) Directive
2011/65/EU Restriction of Certain Hazardous Substances (RoHS) Directive
Note: This declaration covers all product serial numbers from the date this Declaration was
signed onwards.
09.07.2015, Eastbourne
Larry Marini, Senio
r
Technical Manage
r
Date and Place
P200-02-540 Issue G

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Contents
D048-60-880 Issue E
Contents
Section Page
1 Introduction .......................................................................................1
1.1 Scope and definitions ................................................................................................... 1
1.2 Description ................................................................................................................ 1
2 Technical Data ....................................................................................3
2.1 Mechanical data .......................................................................................................... 3
2.2 Performance, operating and storage conditions .................................................................... 3
2.3 Electrical data ............................................................................................................ 3
2.3.1 Electrical supply .........................................................................................................3
2.3.2 Output signal .............................................................................................................4
2.3.3 Gauge and degas enable ................................................................................................ 4
2.3.4 Status outputs ............................................................................................................4
2.3.5 Electrodes ................................................................................................................. 4
2.4 Materials exposed to vacuum .......................................................................................... 4
3 Installation .........................................................................................7
3.1 Unpack and inspect ...................................................................................................... 7
3.2 Fit the AIGX to the vacuum system ................................................................................... 7
3.3 Electrical connections ................................................................................................... 7
3.3.1 Connect to your own supply and control equipment ............................................................... 7
3.3.2 Maximum cable length .................................................................................................. 9
4 Operation ........................................................................................ 11
4.1 Enable and disable the AIGX ..........................................................................................11
4.2 Pressure measurement .................................................................................................11
4.2.1 Calibration in different gases .........................................................................................11
4.3 Emission current selection ............................................................................................12
4.4 Degas the AIGX ..........................................................................................................13
4.5 Over-pressure protection ..............................................................................................13
4.6 Filament selection ......................................................................................................13
4.7 LED status ................................................................................................................13
4.8 Bakeout ...................................................................................................................14
5 Maintenance ..................................................................................... 15
5.1 Fault finding guide ......................................................................................................15
5.2 Replace the body tube .................................................................................................15
5.3 Replace the internal fuse ..............................................................................................15
5.4 Calibration service ......................................................................................................16
6 Storage and Disposal ........................................................................... 17
6.1 Storage ...................................................................................................................17
6.2 Disposal ...................................................................................................................17
7 Spares and Accessories ........................................................................ 19
7.1 Introduction .............................................................................................................19
7.2 Spares .....................................................................................................................19
7.3 Accessories ...............................................................................................................19
For return of equipment, complete the HS Forms at the end of this manual.
gea/0227/07/13

D048-60-880 Issue E
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Edwards and the Edwards logo are trademarks of Edwards Limited.
Contents
Illustrations
Figure Page
1 General View of the AIGX .............................................................................................. 2
2 Dimensions ................................................................................................................ 5
3 Schematic Diagram of Recommended Electrical Connections .................................................... 8
4 Pressure Output Signal of AIGX .......................................................................................12
5 Separate the Electronics Housing from the Body Tube ...........................................................14
6 Fuse Replacement ......................................................................................................16
Tables
Table Page
1 Pins on the AIGX Connector ............................................................................................ 8
2 Maximum Recommended Cable Length .............................................................................. 9
3 Gas Calibration Factors For Various Gases ..........................................................................12
4 LED Status ................................................................................................................13
5 Fault Finding Guide .....................................................................................................15
Associated publications
Publication title Publication number
Vacuum pump and vacuum system safety P300-20-000

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Introduction
D048-60-880 Issue E
1Introduction
1.1 Scope and definitions
This manual provides installation, operation and maintenance instructions for the Edwards Active Ion Gauge (AIGX).
You must use the AIGX as specified in the manual.
Read this manual before you install and operate the AIGX. Important safety information is highlighted as WARNING
and CAUTION instructions; you must obey these instructions. The use of WARNINGS and CAUTIONS is defined below.
CAUTION
Cautions are given where failure to observe the instruction could result in damage to the equipment, associated
equipment and process
The following IEC warning labels appear on the pump:
The units used throughout this manual conform to the SI international system of units of measurement.
1.2 Description
The AIGX is an ion gauge head and gauge controller in a single compact unit. The gauge operates as a hot filament
ionisation gauge, in which the pressure is measured indirectly as a function of the current.
The measurement range of the AIGX is 5 x 10-10 to 5 x 10-2 Torr (6.6 x 10-10 to 6.6 x 10-2 mbar). Three types of vacuum
connections are available: DN16CF, DN40CF and NW25.
The AIGX requires a 14.5 - 30 V d.c. power supply; it has a 0 to 10 V d.c. analogue output which is related to pressure.
A 9-way electrical connector socket on the AIGX (Figure 1, item 1) is used to connect the AIGX to your electrical
supply and voltmeter.
The AIGX is supplied with two filaments. A switch on top of the gauge selects between filament 1 and 2 (Figure 1,
item 2).
There are two levels of emission currents: 0.1 and 1 mA. The 0.1 mA emission current should be used at pressures
higher than 10-5 Torr and the 1mA emission current should be used at pressures lower than 10-5 Torr.
A protection circuit is built into the gauge to prevent operating the gauge at pressures higher than 5 x 10-2 Torr.
WARNING
Warnings are given where failure to observe the instruction could result in injury or death to
people.
Warning - refer to accompanying documentation.
Warning - Edwards offer European customers a recycling service.

D048-60-880 Issue E
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Introduction
The AIGX can be degassed using the degas feature. During degas, the grid voltage is 500 V and the emission current
is 10 mA. The degas is inhibited at high pressure. The maximum duration of degas is three minutes, after which the
gauge returns automatically to its normal mode.
The AIGX is fitted with a status LED (Figure 1, item 3) . This LED indicates the operating status of the gauge.
Figure 1 - General View of the AIGX
1. Electrical connector 3. Status LED
2. Filament select switch 4. Vacuum flange
3
1
2
4
ACTIVE ION GAUGE
AIGX-D-1.33CF
P NO. D04861000
EDWARDS LIMITED
Manor Royal, Crawley, West Sussex
RH10 2LW, ENGLAND

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Technical Data
D048-60-880 Issue E
2TechnicalData
2.1 Mechanical data
2.2 Performance, operating and storage conditions
2.3 Electrical data
2.3.1 Electrical supply
Dimensions See Figure 2
Mass
AIGX-D-NW25 260 g
AIGX-D-DN16CF 300 g
AIGX-D-DN40CF 510 g
Volume of gauge tube 21 cm3
Enclosure rating IP30
Ambient temperature
operation 0 to 40°C
storage -30 to 70°C
Ambient humidity 90% RH (non-condensing)
up to 31°C reducing to
50 % RH at 40°C
Atmosphere Dry non-conductive only
(pollution degree 1)
Bakeout temperature 200°C (with electronics
removed)
Maximum operating altitude 2000 m
Maximum internal pressure 10 bar absolute
Pressure measurement range 5 x 10-10 to 5 x 10-2 Torr
(6.6 x 10-10 to 6.6 x 10-2 mbar)
Voltage +14.5 V to +30 V d.c.
Internal fuse 1 A (T)
Maximum power consumption
Operating 7 W
Degas 14 W
Electrical connector 9-way ‘D’ type male

D048-60-880 Issue E
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Technical Data
2.3.2 Output signal
2.3.3 Gauge and degas enable
2.3.4 Status outputs
* required when you use an external d.c. relay connected to the status outputs
2.3.5 Electrodes
2.4 Materials exposed to vacuum
Measurement range 0.7 V to 8.7 V
Gauge disabled 10.0 V
Minimum load impedance 10 kW
Control sense Active low
Active level < 1.5 V
Load rating 30 V d.c., 100 mA max
Back EMF suppression diode *
Min surge rating 1 A
Min reverse voltage rating 100 V
Emission current
Normal 0.1 or 1 mA
Degas 10 mA
Grid voltage
Normal 180 V
Degas 500 V
Filament bias voltage +30 V
Collector voltage 0 V
Collector Tungsten
Grid Tantalum Pt Clad Mo
Filament Yttria coated iridium
Body Stainless Steel
Feedthrough Stainless Steel and UHV
compatible, glass/ceramic

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Technical Data
D048-60-880 Issue E
Figure 2 - Dimensions
A
B
70
70

D048-60-880 Issue E
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Installation
D048-60-880 Issue E
3 Installation
3.1 Unpack and inspect
Remove all packing materials and protective covers and check the AIGX .
If the AIGX is damaged, notify your supplier and the carrier in writing within three days; state the Item Number of
the gauge together with your order number and your supplier’s invoice number. Retain all packing materials for
inspection. Do not use the AIGX if it is damaged.
If the AIGX is not to be used immediately, replace the protective covers. Store the AIGX in suitable conditions as
described in Section 6.
3.2 Fit the AIGX to the vacuum system
The AIGX can be mounted in any orientation. To avoid the build-up of debris or condensable material in the body
tube of the AIGX (which will probably cause pressure measurement errors), we recommend that you install the AIGX
vertically with the flange facing down.
Use a copper gasket and screws to connect the DN16CF and DN40CF flanges of the AIGX to a similar flange on
your vacuum system. Use an O-ring / centring-ring or Co-Seal and metal clamp to connect the NW25 flange of the
AIGX to a similar flange on your vacuum system.
Note: O’ rings are not recommended for systems where UHV pressures are required.
3.3 Electrical connections
3.3.1 Connect to your own supply and control equipment
Note: Do not connect the electrical supply common (pin 2) to the signal common (pin 5). If you do, the AIGX
pressure output signal will be inaccurate.
A schematic diagram of the recommended electrical connections to the AIGX is shown in Figure 3.
The pins on the AIGX connector are used as shown in Table 1. The specification of the electrical supply, d.c. relay
and back EMF suppression diode are given in Section 2.
The connection to Pins 5 and 9 are optional. Make the connection to these pins if you want to monitor the emission
status and degas status signals. If you want to connect d.c. relays to pins 5 and 9, you must connect a suppression
diode between pins 4 to 5 and 4 to 9 to protect the AIGX from transient voltage generated when the d.c. relays are
switched off.
Connect a switch between pins 1 and 2 to enable and disable the gauge.
Connect a switch between pins 6 and 2 to enable and disable the degas function.
WARNING
The AIGX must be connected to an earthed (grounded) vacuum system. For gauges with a NW25
flange, a conductive metallic clamping ring must be used.
WARNING
If the AIGX malfunctions, the AIGX pressure output may be incorrect. If such a failure could result
in damage to equipment or cause injury to people, you must install a suitable control system to
indicate the failure and, if necessary, to close down your process system.

D048-60-880 Issue E
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Installation
Connect a switch between pins 8 and 2 to select between 0.1 and 1.0 mA emission current. Connecting pin 8 to pin
2 will increase the emission current from 0.1 to 1.0 mA.
Figure 3 - Schematic Diagram of Recommended Electrical Connections
Table 1 - Pins on the AIGX Connector
Pin No. Use
1 Gauge enable
2 Supply common
3 Signal output
4Supplypositive
5 Degas status
6 Degas enable
7 Signal common
8 Emission current select
9 Emission status
F
B
A
E
C
G
D
H
CDC
RELAY
VOLTAGE
SUPPLY
DC
RELAY
(VOLTMETER)
SIGNAL
VOLTAGE
1
2
3
4
5
6
7
8
9
0V
+
1
9
A AIGX connector (socket)
B Cable electrical (plug)
C Back EMF suppression diode (optional)
D Degas status relay (optional)
E Emission status relay (optional)
F Gauge enable switch
G Degas enable switch
H Emission current select switch
I View of AIGX connector

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Installation
D048-60-880 Issue E
3.3.2 Maximum cable length
The maximum cable length is dependent on the conductor cross-section and the supply voltage used. The following
maximum cable lengths are recommended:
The common mode signal voltage (that is, the voltage between signal common and supply common) could be as much
as 2.5 V with long cables due to the voltage drop in the supply cable. You should ensure that the signal voltage
measurement will operate correctly.
Table 2 - Maximum Recommended Cable Length
Conductor cross-section 24 V Supply 15 V Supply
0.75 mm2 100 m 10 m
0.5 mm2 75 m 6 m
0.34 mm2 50 m 4.5 m
0.22 mm2 30 m 3 m

D048-60-880 Issue E
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Operation
D048-60-880 Issue E
4 Operation
4.1 Enable and disable the AIGX
CAUTION
The gauge should not be operated at pressures higher than 5 x 10-2 Torr (6.6 x 10-2 mbar). Operating the AIGX
at high pressures may reduce the lifetime of the filament.
To enable (switch on) the AIGX, connect pin 1 to pin 2. To disable (switch off) the AIGX, disconnect pin 1 from pin 2.
When the AIGX is enabled, the output signal will remainat 10.0 V whilst the emission current is being stabilised. This
will take typically 5 seconds (may be longer at lower pressures). After this time the output signal will indicate
pressure.
4.2 Pressure measurement
Convert the output signal to pressure using the following equation:
P = 10(V - 10) Torr
P = 10(V - 9.875) mbar
P = 10(V - 7.875) Pa
where V is the measured voltage in volts. Refer to Figure 4. This formula is valid for the range 0.7 V to 8.7 V.
4.2.1 Calibration in different gases
The equation given in Section 4.2 is for air or nitrogen only. For other gases, the indicated pressure has to be
multiplied by a gas calibration factor (GCF).
Table 3 lists the gas calibration factor for most commonly used gases.
WARNING
Do not use the AIGX to measure the pressure of explosive or flammable gases or mixtures.
WARNING
During operation, the surface of the ion gauge tube might become hot. To avoid risk of injury, do
not touch the tube whilst the gauge is operating. Switch off the gauge and allow to cool down for
few minutes before handling.
WARNING
Disconnect the electrical supply cable from the AIGX before you remove the AIGX from the vacuum
system. High voltages are generated inside the AIGX.

D048-60-880 Issue E
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This page has been intentionally left blank.
Figure 4 - Pressure Output Signal of AIGX
4.3 Emission current selection
The AIGX has two levels of emission current: 0.1 mA and 1.0 mA. You can use the high emission current up to a
pressure of 1 x 10-3 Torr (1.3 x 10-3 mbar), and the low emission current up to a pressure of 5 x 10-2 Torr
(6.6 x 10-2 mbar). However, to extend the lifetime of the gauge, we recommend that you use the low emission
current at pressures higher than 1 x 10-5 Torr (1.3 x 10-5 mbar). To select the higher emission current, connect pin
8 to pin 2. To select the lower emission current, disconnect pin 8 from pin 2.
You can monitor the emission status at pin 9. When the emissions are off, the open collector transistor is off. When
the emissions are on, the open collector transistor is on.
Table 3 - Gas Calibration Factors For Various Gases
Gas GCF
Helium 5.7
Argon 0.75
Neon 3.3
Krypton 0.5
Xenon 0.35
Hydrogen 2.4
Oxygen 1.0
Carbon Monoxide 1.15
Carbon Dioxide 0.7
0
1
2
3
4
5
6
7
8
1E-10 1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 1E-2 1E-1 1E+0 1E+1
Indicated Pressure
mbar torr Pascal

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Operation
D048-60-880 Issue E
4.4 Degas the AIGX
CAUTION
You must degas the AIGX regularly. Failure to do so will affect the performance and reduce the lifetime of the
gauge.
During use in contaminating environments the gauge electrodes become coated in insulating layers, eventually
resulting in premature failure of the product. This can be prevented by regular use of the degas feature. Typically,
degas will be required on a weekly basis although the interval will depend on the level of contamination.
The degas operation is also recommended if measurement of low pressure are required.
During degas, the grid will be heated to high temperature, sufficient to remove absorbed gases and some
contamination.
Degas the AIGX when the pressure is below 1 x 10-5 Torr (1.3 x 10-5 mbar). The degas is inhibited when the pressure
is above 1 x 10-4 Torr (1.3 x 10-4 mbar). The gauge will automatically return to the normal operation mode after 3
minutes.
To enable degassing of the AIGX, connect pin 6 to pin 2. To disable degassing of the AIGX, disconnect pin 6 from pin 2.
You can monitor the degas status at pin 5. When the degas is operating the open collector transistor is on. When
the degas is off, the open collector transistor is off.
4.5 Over-pressure protection
The gauge will automatically switch off when the measured pressure rises above 5 x 10-2 Torr (6.6 x 10-2 mbar) or
1 x 10-3 Torr (1.33 x 10-3 mbar) if the high emission current is selected. If this occurs then the LED status will indicate
over-pressure trip. Refer to Section 4.7.
4.6 Filament selection
The AIGX has two filaments, 1 and 2. To select either of these filaments, use the sliding switch at the top of the
gauge. Make sure that the gauge is turned off before switching between filaments.
4.7 LED status
The AIGX is fitted with a tri-coloured LED which can be used to monitor the status of the gauge according to Table 4.
Table 4 - LED Status
Colour Status
Off No power to the gauge or malfunction
Amber Power on, gauge disabled
Green/Amber (alternating) Emissions start-up
Green Emission on
Green (slow flashing) Degas on
Red (flashing) Emission error
Red Over-pressure trip

D048-60-880 Issue E
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Operation
4.8 Bakeout
The AIGX tube can be baked to temperatures up to 200°C (392°F)after removing the electronics housing. Refer to
Figure 5 and the procedure in Section 5.2 to remove and refit the electronics housing.
Ensure that the tube has cooled down before refitting the electronics housing.
Figure 5 - Separate the Electronics Housing from the Body Tube
1. Electronics housing 3. Body tube assembly
2. Fixing screws 4. Locating lugs
1
2
4
3
2
ACTIVE ION GAUGE
AIGX-D-1.33CF
P NO. D04861000
EDWARDS LIMITED
Manor Royal, Crawley, West Sussex
RH10 2LW, ENGLAND

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Maintenance
D048-60-880 Issue E
5Maintenance
5.1 Fault finding guide
5.2 Replace the body tube
Refer to Figure 5 and use the following procedure to replace the body tube.
1. Turn off the gauge.
2. Switch off the AIGX electrical supply and disconnect the electrical supply cable.
3. Remove the AIGX from the vacuum system.
4. Using a suitable screwdriver, remove the two M3 screws (item 2) from the sides of the electronics housing (item
1).
5. Pull the electronics housing (item 1) to remove it from the body tube assembly (item 3).
6. Fit the new body tube assembly (item 3) to the electronics housing (item 1). Take care to ensure that the
locating lugs (item 4) on the body tube assembly (item 3) are aligned with the mating recess in the electronics
housing (item 1). Note that the electronics housing (item 1) can only fit one way round on the body tube
assembly (item 3).
7. Refit the two M3 screws to the sides of the AIGX.
5.3 Replace the internal fuse
If you suspect that the internal fuse has blown, you should check that the voltage and polarity of the electrical supply
are correct before replacing the fuse.
To replace the fuse refer to Figure 6 and use the following procedure:
WARNING
Disconnect the electrical supply cable before you start any maintenance. High voltages are
generated inside the AIGX.
Table 5 - Fault Finding Guide
Symptom Possible Cause Remedy
LED Not Lit Supply connection incorrect or
faulty. Supply polarity reversed. Check electrical supply and connections.
Internal fuse blown. Replace fuse. Refer to Section 5.3
Over-pressure trip The pressure rose too high whilst the
AIGX was operating. Reduce the pressure and re-enable the AIGX.
Emission error The AIGX was enabled when the
pressure was too high. Reduce the pressure and re-enable the AIGX.
Filament contaminated. Filament
open circuit. Switch to the other filament. If both filaments give the error, replace the body
tube. Refer to Section 5.2.
Electrical supply insufficient to drive
the AIGX. Check that supply voltage/current specifications meet requirement in
Section 2.3.1.

D048-60-880 Issue E
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Maintenance
1. Switch off the electrical supply and remove the electrical supply connector from the gauge.
2. Using a suitable screwdriver, remove the four M3.5 screws from the top of the gauge.
3. Remove the gauge lid, ensuring the screw on the underside of the lid is not bent.
4. The fuse will now be visible on the PCB. Hold the board down and then pull the fuse from it’s fuseholder using
an appropriate tool (for example, a small pair of pliers).
5. The replacement fuse is supplied mounted in a fuseholder. Remove the new fuse from its fuseholder and discard
the new fuseholder.
6. Push the new fuse into the fuseholder on the PCB.
7. Refit the gauge lid ensuring that the screw is fitted in the shrouded earth socket next to the main connector.
Refit the four M3.5 screws.
8. Apply power to the gauge and check that the LED is illuminated.
Replacement fuses are available from Edwards. Refer to Section 7.2.
Figure 6 - Fuse Replacement
5.4 Calibration service
A calibration service is available for all Edwards gauges. Calibration is by comparison with reference gauges,
traceable to National Standards. Contact Edwards for details.
1. Fuse holder 2. Shrouded earth socket
3
2