Bayard-Alpert Gauge
BAG402

Operating Manual
Incl. EC Declaration of Conformity

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Product Identification
In all communications with INFICON, please specify the information given on the product nameplate. For convenient reference copy that information into the space provided below.

INFICON AG, LI-9496 Balzers

Model:
PN:
SN:
V

W

ValidityThis document applies to products with the following partnumbers:353-600 (DN 25 ISO-KF)
353-601 (DN 40 CF-R)
The part number (PN) can be taken from the product nameplate.
If not indicated otherwise in the legends, the illustrations in thisdocument correspond to the gauge with vacuum connection
DN 25 ISO-KF. They apply to gauges with the other vacuum
connection by analogy.
We reserve the right to make technical changes without priornotice.

2

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Intended Use
The BAG402 gauge has been designed for vacuum measurement of gases and gas mixtures in a pressure range of
5×10-10 … 2.7×10-2 mbar.
It must not be used for measuring flammable or combustible
gases in mixtures containing oxidants (e.g. atmospheric oxygen)
within the explosion range.

Funktion
The gauge functions with a Bayard-Alpert hot cathode ionization
measurement system.
Over the whole measuring range, the gauge has a continuous
characteristic curve and its measuring signal is output as logarithm of the pressure.

Scope of Delivery
1× gauge
1× pin for adjusting settings via buttons
1× Operating Manual German
1× Operating Manual English

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Contents
Product Identification
Validity
Intended Use
Funktion
Scope of Delivery

2
2
3
3
3

1 Safety
1.1 Symbols Used
1.2 Personnel Qualifications
1.3 General Safety Instructions
1.4 Liability and Warranty

6
6
6
7
7

2 Technical Data
2.1 Measuring Signal vs. Pressure
2.2 Gas Type Dependence

8
13
14

3 Installation
3.1 Vacuum Connection
3.1.1 Removing and Installing the Electronics Unit
3.1.2 Using the Optional Baffle
3.2 Power Connection

15
15
18
19
23

4 Operation
4.1 Status Indicator
4.2 Putting the Gauge Into Operation
4.3 Gas Type Dependence
4.4 Contamination (Degas)
4.5 Filament Selection
4.5.1 Via the Diagnostic Port (RS232C)
4.5.2 Via the Button on the Gauge
4.6 Diagnostic Port (RS232C)
4.6.1 Description of the Functions

25
25
25
28
28
29
29
29
30
30

5

37

Deinstallation

6 Maintenance, Repair
6.1 Cleaning the Gauge
6.2 What to Do in Case of Problems
6.3 Replacing the Sensor

4

38
38
39
42

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7

Returning the Product448Disposal

45

9

Options

46

10

Accessories

46

11

Spare Parts

46

EC Declaration of Conformity

47

For cross-references within this document, the symbol (→  XY)
is used.

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1

Safety1.1

Symbols Used
DANGER
Information on preventing any kind of physical injury.

WARNING
Information on preventing extensive equipment and environmental damage.

CautionInformation on correct handling or use. Disregard can lead tomalfunctions or minor equipment damage.
Notice<…>1.2

Labeling

Personnel Qualifications
Skilled personnel
All work described in this document may only be carried out by
persons who have suitable technical training and the necessary experience or who have been instructed by the end-userof the product.

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1.3

General Safety Instructions• Adhere to the applicable regulations and take the necessary
precautions for the process media used.
Consider possible reactions with the product materials.
Consider possible reactions (e.g. explosion) of the process
media due to the heat generated by the product.
• Adhere to the applicable regulations and take the necessary
precautions for all work you are going to do and consider thesafety instructions in this document.
• Before beginning to work, find out whether any vacuum components are contaminated. Adhere to the relevant regulations
and take the necessary precautions when handling contaminated parts.
Communicate the safety instructions to all other users.

1.4

Liability and Warranty
INFICON assumes no liability and the warranty becomes nulland void if the end-user or third parties• disregard the information in this document• use the product in a non-conforming manner• make any kind of interventions (modifications, alterations etc.)
on the product• use the product with accessories not listed in the productdocumentation.
The end-user assumes the responsibility in conjunction with theprocess media used.
Gauge failures due to contamination or wear and tear, as well as
expendable parts (e.g. filament), are not covered by the warranty.

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2Technical Data
Measurement range (Luft, O2,
CO, N2)
Accuracy
1×10-8 … 10-2 mbar
Repeatability
1×10-8 … 10-2 mbar
Gas type dependence
Emission current
p ≤7.2×10-6 mbar
7.2×10-6 < p < 3×10-5 mbar 1)
3×10-5 < p < 3.2×10-2 mbar
Emission current switching
25 µA  5 mA
5 mA  25 µA
Filament
NumberMeans of selection(→  29)

5×10-10 … 2.7×10-2 mbar,
continuous
15% of reading(after 10 min. stabilization)
5% of reading(after 10 min. stabilization)→  145 mA
25 µA or 5 mA
25 µA
7.2×10-6 mbar
3.0×10-5 mbar2
• controlled by gauge(default)• via the button on gauge• via the diagnostic port

Settling time of
measurement signal after
filament change
Filament status<4 sindicator (→  25)
Emission ON<+6 V (dc), low active
Emission OFF>+10 V (dc), high active
Automatic emission switch off at p > 3.2×10-2 mbar.

1)

8

Depending on whether the pass through the pressure range is increasing or decreasing (hysteresis range).
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Degaselectro bombardement, may
be switched on at<7.2×10-6 mbar

Degas current(p <7.2×10-6 mbar)≈20 mA<+6 V (dc), low active>+10 V (dc), high active<3 minutes, followed by automatic stop
In degas mode, the gauge keeps supplying pressure readings,
the tolerances of which can be higher than during normal operation.
Degas acts only upon the active filament.
Degas ON
Degas OFF
Duration

Voltage range (analog output)
Measurement range
Voltage vs. pressure
Error signal, emission isswitched off
Minimum load impedance

0 … +10.5 V+0.57 … +8.31 V
1 V/decade, logarithmic

Solid state relays

Switching timedegas status (pin 5)
gauge status (pin 9)<40 V (ac) / (dc), ≤0.1 A
resistive<30 msDiagnostic port connection
Cable length

Jack connector. 2.5 m, 3-pin≤2.5 mContact rating

tina92e1(2014-12)+10.2 V10 kΩ

9Supply

DANGER
The gauge may only be connected to power supplies that conform to the requirements of agrounded protective extra-low voltage (PELV). The
connection to the gauge has to be fused.
Supply voltage
at the gauge 2)
RipplePower consumption
Standard
Degas
Emission start (<200 ms)
Power consumption
Fuse necessary
Power connection
Sensor cable
Cable length

Materials exposed to vacuum
Housing, supports, screens
Feedthroughs
Insulator
CathodeCathode holder
Internal volume
DN 25 ISO-KF
DN 40 CF-R
Permissible pressure2)

10+20 … +28 V (dc)
≤2 Vpp≤0.5 A≤0.8 A≤1.4 A≤18 W≤1.25 ATD-Sub, 9-pin, male
9-pin, shielded≤35 m, 0.25 mm2/conductor≤50 m, 0.34 mm2/conductor≤100 m, 1.0 mm2/conductor
stainless steel
NiFe, nickel plated
glass
iridium, yttriumoxid (Y2O3)
molybdenum, platinum3≈24 cm3≈34 cm2 bar (absolute)

The minimum voltage of the power supply unit must be increased proportionally to the length of the sensor cable.
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Permissible temperatures
Operation
Bakeout
Storage
Relative humidity
Year's mean
During 60 days
Mounting orientation
Use
Degree of protection≤65% (non-condensing)≤85% (non-condensing)any
indoors only, altitude up to2000 m NN
IP 30

Weight353-600,
353-601≈450 g≈710 g3)

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0 °C … +50 °C≤80 °C 3)–20 °C … +70 °C

Flange temperature, electronics unit removed, horizontally mounted.

(2014-12)11

Dimensions [mm]59Man. FIL

111

1.3

67

FIL

PWR

DN 25 ISO-KF

12

47

42

DIA

DN 40 CF-R

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2.1

Measuring Signal vs. Pressure
Pressure p
1E+01
1E+00

Pa
mbar
Torr

1E–02
1E–03
1E–04
1E–05
1E–06

Emission off, error

1E–01

1E–07
1E–08
1E–09
1E–10

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

8.31

0.57

Measurement signal U [V]p = 10(U-c)

c

U = c + log p

⇔

mbar
9.875

Pa
7.875

Torr
10

where p pressure
U measurement signal
c constant (pressure unit dependent)

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13

2.2

Gas Type Dependence
The gas type dependence can be compensated by means of thefollowing formula (gauge adjusted for air):peff = C × indicated pressure
where:

Gas typeC

Air (N2, O2, CO)
Xe
Kr
Ar
H2
Ne
He

1.0
0.4
0.5
0.8
2.4
4.1
5.9

The above calibration factors are mean values.
A mixture of gases and vapors is often involved. In thiscase, accurate determination is only possible with apartial-pressure measuring instrument.

14

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3Installation

3.1

Vacuum Connection
DANGERDANGER: overpressure in the vacuum system>1 barInjury caused by released parts and harm causedby escaping process gases can result if clamps are
opened while the vacuum system is pressurized.
Do not open any clamps while the vacuum system
is pressurized. Use the type clamps which aresuited to overpressure.

DANGERDANGER: protective ground
Products that are not correctly connected to groundcan be extremely hazardous in the event of a fault.
Electrically connect the gauge to the groundedvacuum chamber. This connection must conform to
the requirements of a protective connection according to EN 61010:• CF connections fulfill this requirement• For gauges with a KF flange, use a conductive
metallic clamping ring.

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Caution
Caution: vacuum component
Dirt and damages impair the function of the vacuum component.
When handling vacuum components, take appropriate measures to ensure cleanliness and prevent
damages.

CautionCaution: dirt sensitive area
Touching the product or parts thereof with barehands increases the desorption rate.
Always wear clean, lint-free gloves and use clean
tools when working in this area.
The gauge may be mounted in any orientation. To keep condensates and particles from getting into the measuring chamber,preferably choose a horizontal to upright position.
The gauge is supplied with a built-in grid. For potentially contaminating applications and to protect the electrodes against lightand fast charged particles, installation (→  46) of the optional
baffle is recommended (→  19).
When installing the gauge, allow for installing/deinstalling theconnectors and accommodation of cable loops.

16

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Remove the protective lid and connect the product to thevacuum system.
Vacuum connection free of grease.

Seal with centerring ring

Protective lid
Clamp

Keep the protective lid.

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3.1.1

Removing and Installing the Electronics Unit
Required tools / material• Allen wrench, AF 2.5
Removing the electronics unit

 Unscrew the hexagon socket set screw (1) on the side ofthe electronics unit (2).
12

 Remove the electronics unit without twisting it.

18

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Installing the electronics unit Place the electronics unit (2) on the sensor (3) (be careful
to correctly align the pins and notch (4)).

4

2

3

 Slide the electronics unit in to the mechanical stop and lockit with the hexagon socket set screw.

3.1.2

Using the Optional Baffle
In severely contaminating processes and to protect measurement electrodes optically against light and fast charged particles,
replacement of the built-in grid by the optional baffle (→  46) isrecommended.
Precondition
Gauge deinstalled ("Deinstallation" →  37).

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Required tools / material• Baffle (→  46)• Pointed tweezers• Pin• Screwdriver
Installation

 Carefully remove the grid with tweezers.

20

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 Carefully place the baffle onto the sensor opening.

 Using a pin, press the baffle down in the center until itcatches.

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Deinstallation
Carefully remove the baffle with the screwdriver.

Do not damage
the sealing surface

22

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3.2

Power Connection
Make sure the vacuum connection is properly made(→  15).

DANGER
The gauge may only be connected to power supplies that conform to the requirements of agrounded protective extra-low voltage (PELV). The
connection to the gauge has to be fused.
Ground loops, differences of potential, or EMC problems
may affect the measurement signal. For optimum signal
quality, please do observe the following notes:• Use an overall metal braided shielded cable. The
connector must have a metal case.
• Connect the supply common with protective grounddirectly at the power.
• Use differential measurement input (signal commonand supply common conducted separately).
• Potential difference between supply common andhousing ≤16 V (overvoltage protection).

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23

If no sensor cable is available, make one according to the following diagram. Connect the sensor cable.
Emission on

Low active

1
9

Low active

6

Measuring
signalDegas on

3

+

7

–

5

Vs

4

+
–

2

Electrical connection
Pin 1
Pin 2
Pin 3
Pin 4
Pin 5
Pin 6
Pin 7
Pin 8
Pin 9

24

Emission on/off (Low active)
Supply common GND
Signal output (measuring signal)
Supply (Vs)
Degas status
Degas on/off (Low active)
Signal common
n.c.
Gauge status

6

1

9

5

D-Sub, 9-pin
femalesoldering side

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4

Operation

4.1

Status Indicator
Filament Status<FIL>

Supply voltage
<PWR>
FIL

PWR
DIA

Supply voltage <PWR>

Indicator

No supply voltage
Supply voltage ok

off
lid solid green

Filament status <FIL>

Emission

Indicator

off
on
on
on
on

off
lid solid green
blinking green
lid solid red
blinking red–
Both filaments ok
One filament broken
Both filaments broken
Emission current not stable

4.2

Putting the Gauge Into Operation
CautionTurn on the emission only at pressures<2.7×10-2 mbar to prevent excessive contamination.

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When the supply voltage is applied and the emission is switchedon via pin 1 (low active), the measuring signal is available at thesignal output (stabilizing time approx. 2 s). The solid state relay"Gauge status" (pin-9) is closed.
If pressure rises over the switching threshold(p = 3.2×10-2 mbar), the hot cathode is switched off automatically.

Measuring Principle, Measuring Behavior
The hot cathode measuring system uses an electrode system
according to Bayard-Alpert which is designed for a low X-ray
limit.
The measuring principle of this measuring system is based on
gas ionization. Electrons emitted by the operating filament (F1 or
F2) ionize a number of molecules proportional to the pressure in
the measuring chamber.
The ion collector (IC) collects the produced ion current I+ andfeeds it to the electrometer amplifier of the measurement instrument. The ion current is dependent upon the emission current Ie,
the gas type, and the gas pressure p according to the following
relationship:
I+ = Ie × p × C
Factor C represents the sensitivity of the gauge head. It is
generally specified for N2.
The lower measurement limit is 5×10-10 mbar (gauge metal
sealed).
To usefully cover the whole range of 5×10-10 … 2.7×10-2 mbar, alow emission current is used in the high pressure range (finevacuum) and a high emission current is used in the low pressure
range (high vacuum). The switching of the emission current
takes place at decreasing pressure at approx. 7.2×10-6 mbar, atincreasing pressure at approx. 3.0×10-5 mbar. At the switching
threshold, the BAG402 can temporarily (<2 s) deviate from thespecified accuracy.

26

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IC

F1
F2

Diagram of the Bayard-Alpert
measuring system:
F1 hot cathode (filament 1)
F2 hot cathode (filament 2)
IC ion collector
EC anode (electron collector)
FS filament selector switch

EC

FS

+

40V

–

–

200V

+

(Degas 2.5V) (Degas 250V)
EC
F1

F2
IC

Dual filament feature
BAG402 sensors are equipped with two identical filaments. They
are permanently monitored by the gauge electronics. In case ofa filament breakage, the gauge will immediately react and switch
over to the second (undamaged) filament. During the changeover procedure, the last valid pressure value before filament
failure will be output. As soon as the second filament is operating
and the emission parameters have settled (t <4s), the measuring
circuit resumes operation.
A "Hot Cathode Warning" is generated during this switch overcycle. The filament status indicator <FIL> on the gauge will
display the incident (blinking green, →  25). The filament status
can also be read via the diagnostic port (→  30).
In case of two broken filaments, a "Hot Cathode Error" is generated. The filament status indicator <FIL> lid solid red (→  25).
In this case, the sensor has to be replaced (→  42).

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At the beginning of every "Emission ON" cycle, the gauge alternates between filaments in order to age both filaments evenly.
However, filament selection can be commanded via the buttonon the gauge or via the diagnostic port (→  30).
We recommend to replace the sensor as soon as thefirst filament failure has been detected (replacing thesensor →  42).

4.3

Gas Type Dependence
The measurement value is gas dependent. The pressure reading
applies to dry air, O2, CO and N2. For other gases, it has to becorrected (→  14).

4.4

Contamination (Degas)
Gauge failures due to contamination or wear and tear, as well as
expendable parts (e.g. filament), are not covered by thewarranty.
Deposits on the electrode system of the Bayard-Alpert gauge
can lead to unstable measurement readings.
The degas process allows in-situ cleaning of the electrode system by heating the electron collector grid to approx. 700 °C byelectron bombardment.
This function can be activated via pin 6 (the solid state relay"Degas status" (pin 5) is closed during the degas process). The
gauge automatically terminates the degas process after threeminutes, if it has not been stopped before.
The degas process should be run at pressures below
7.2×10-6 mbar (emission current 5 mA).

28

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For a repeated degas process, the control signal first has tochange from ON (<+6 V) to OFF (>+10 V), to then start degas
again with a new ON (+6 V) command. It is recommended thatthe degas signal be set to OFF again by the system control after
3 minutes of degassing, to achieve an unambiguous operating
status.
A new degas cycle can only be started after a waitingtime of thirty minutes.
Degas acts only upon the active filament.

4.5

Filament Selection

4.5.1

Via the Diagnostic Port (RS232C)
In automatic mode (AUTO) (default) the gauge automaticallyalternates between filaments in order to age both filaments
evenly. However, in manual mode (MAN), filament selection canbe commanded via the diagnostic port <DIA> (→  35, "Filament
Control Mode").

4.5.2

Via the Button on the Gauge
Precondition: Emission is off

Briefly press the button with a pin(max. ø1.3 mm). The gauge changes
to the other filament:
The filament status indicator <FIL>• blinks once: filament 1 is active• blinks twice: filament 2 is active.
When the button is pressed for the
first time, the gauge simultaneously
changes to the manual mode (MAN).

Filament statusindicator <FIL>

Press thebuttonbrieflymax. ø1.3
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Reset the gauge to the automatic mode (AUTO):• keep the button depressed for at least five seconds, or• via the diagnostic port <DIA> (→  35, "Filament Control
Mode").

4.6

Diagnostic Port (RS232C)
The RS232C interface allows transmission of digital measurement dataand instrument conditions as well as
the setting of instrument parameters.

Diagnostic port <DIA>

FIL

PWR
DIA

4.6.1

Description of the Functions
D The interface works in duplex mode. A nine byte string is sent
continuously without a request approx. every 6 ms.
Commands are transmitted to the gauge in a five byte input(receive) string.
Operational parameters• Data rate
• Byte• Handshake• Parity bit

9600 Baud(set value)

8 data bits
1 stop bit
nonone

4.6.1.1 Output String (Transmit)
The complete output string (frame) is nine bytes (byte 0 … 8).
The data string is seven bytes (byte 1 … 7).

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Format of the output string
Byte No01

Function
Length of data string
Page number

Value

Comment7
5

set value
hot cathodegauges2

Status→ Status byte

3

Error

→ Error byte

4

Measurement highbyte

5Measurement low
byte

0 … 255

6

Software version

0 … 255
0 … 255

7
8

Sensor type
Check sum14
0 … 255→ Calculation ofpressure value→ Calculation ofpressure value→ Software
version(for BAG402)→ Synchronization

Synchronization
Synchronization of the master is achieved by testing three bytes:
Byte No01

Function
Length of data string
Page number

Value
7
5

8

Check sum of bytes
No 1 … 7

0 … 255

4)

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Comment
set value
hot cathodegaugeslow byte ofcheck sum 4)High order bytes are ignored in the check sum.

(2014-12)31

Status byte
Bit 1

Bit 0

Definition

0
0

0
1

emission off

1
1

0
1

emission 25 μA
emission 5 mA
degas

Bit 2
x

Definition
not usedBit 3

Definition
toggle bit, changes with every stringreceived correctly

0⇔1
Bit 5
–

Bit 4
–

Definition
not used

Bit 6
0
1

Definition
filament 1 active
filament 2 active

Bit 7

Definitionx

not usedError byte
Bit 6

Bit 5

Bit 4

Bit 2

x
x
1

x
1
x

1
x
x

x
x
x

5)
6)

32

Definition
hot cathode error 5)
hot cathode warning 6)electronics error / EEPROM
error

Both filaments broken.
One filament broken.
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Software version
The software version of the gauge can be calculated from thevalue of byte 6 of the transmitted string according to the following rule:
Versions No = WertByte 6 / 20
(Example: According to the above formula, ValueByte 6 of 32
means software version 1.6)
Calculation of the pressure value
The pressure can be calculated from bytes 4 and 5 of the transmitted string. Depending on the currently selected pressure unit(→ byte 2, bits 4 and 5), the appropriate rule must be applied.
As result, the pressure value results in the usual decimal format.
pmbar = 10((high Byte × 256 + low Byte) / 4000 - 12.5)
pTorr= 10((high Byte × 256 + low Byte) / 4000 - 12.625)

pPa= 10((high Byte × 256 + low Byte) / 4000 - 10.5)

Alternative calculation with the integer value ("press") frombytes 4 and 5):
pmbar = 10((press) / 4000 - 12.5)

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Example
The example is based on the following output string:
Byte No

0

1

2

3

4

5

6

7

8

Value

7

5

0

0

117

48

20

14

204

The instrument or receiver interprets this string as follows:
Byte No01
23

Function

Value

Comment

Length ofdata string
Page number
Status7

set value

5
0

Error

0

hot cathode gauge
emission = offpressure unit = mbar
filament 1 active
no errorcalculation of the pressure:p = 10((117 × 256 + 48) / 4000 - 12.5) =1×10-5 mbar
Software version = 20 / 20 =1.0
BAG4025 + 0 + 0 + 117 + 48 + 20 +
14 = 204dec = 00 CChex
High order byte is ignoed Check sum = CChex = 204dec

Measurement

4
5
6
7
8

34

High byte
Low byte
SoftwareversionSensor type
Check sum

117
48
20
14
204

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4.6.1.2 Input String (Receive)
For transmission of the commands to the gauge, a string (frame)of five bytes is sent (without <CR>). Byte 1 … 3 form the data
string.
Format of the input string
Byte No
0

Function

Value

Comment3

Set value

1

Length of data
string
Data

2

Data

→ admissible input strings

3

Data

→ admissible input strings

4

Check sum (frombytes No 1 … 3)

→ admissible input strings

0 … 255(low byte of sum) 7)

Admissible input strings
For commands to the gauge, the following strings are defined(values in decimal notation):
Command0

1

Byte No2

3

4 8)

Switch degas on(switched off automaticallyafter 3 minutes)
Switch degas off (before
3 minutes)

3

0x10

0xC4

1

0xD5

3

0x10

0xC4

0

0xD4

Switch emission on
Switch emission off

3
3

0x40
0x40

0x10
0x10

1
0

0x51
0x50

Set Filament Control Modeto AUTO 9), 10)

3

0x10

0xD3

0

0xE3

7)
8)
9)

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High order bytes are ignored in the check sum.
Only low order byte of sum (high order byte is ignored).
Defines the Filament Control Mode (→  29):
AUTO = Selection of filament automatically controlled by the gauge
MAN = Selection of filament controlled via interface.

(2014-12)35

Set Filament Control Modeto MAN 9), 10)
Power-failure-safe storageof the Filament Control
Mode 9), 10)

3

0x10

0xD3

0

0xE4

3

0x20

0x0D

–

0x2D

Select filament 1
Select filament 2 11)Power-failure-safe storageof selected filament 11), 10)
Read filament status

3
3

0x10
0x10

0xD2
0xD2

0
1

0xE2
0xE3

3
3

0x20
0x10

0x0C
0xD4

–
–

0x2C
0xD4

Read software version

3

0x00

0xD1

–

0xD1

Reset
Delete sensor history
Safe all EEPROM device
parameters
Safe all EEPROM sensor
parameters

3
3

0x40
0x40

0
0xFF

0
–

0x40
0x3F

3

0x40

0x40

–

0x80

3

0x40

0x41

–

0x81

11)

10)
11)

36

The parameter is stored non-volatile.
The "Select filament x" command can be sent any time but is only
executed if the gauge is in the "Emission OFF" state.
tina92e1(2014-12)

5

Deinstallation
DANGERDANGER: contaminated parts
Contaminated parts can be detrimental to healthand environment.
Before beginning to work, find out whether any
parts are contaminated. Adhere to the relevant
regulations and take the necessary precautions
when handling contaminated parts.

CautionCaution: vacuum component
Dirt and damages impair the function of the vacuum component.
When handling vacuum components, take appropriate measures to ensure cleanliness and prevent
damages.

CautionCaution: dirt sensitive area
Touching the product or parts thereof with barehands increases the desorption rate.
Always wear clean, lint-free gloves and use clean
tools when working in this area.

 Vent the vacuum system.
 Put the gauge out of operation and disconnect the sensor
cable.
tina92e1(2014-12)37

 Remove gauge from the vacuum system and install theprotective lid.

6

Maintenance, Repair
Gauge failures due to contamination and wear and tear,as well as expendable parts (e.g. filament), are notcovered by the warranty.
INFICON assumes no liability and the warranty becomes nulland void if any repair work is carried out by the end-user or third
parties.

6.1

Cleaning the Gauge
DANGERDANGER: contaminated parts
Contaminated parts can be detrimental to healthand environment.
Before beginning to work, find out whether any
parts are contaminated. Adhere to the relevant
regulations and take the necessary precautions
when handling contaminated parts.

38

tina92e1(2014-12)

Caution
Caution: vacuum component
Dirt and damages impair the function of the vacuum component.
When handling vacuum components, take appropriate measures to ensure cleanliness and prevent
damages.

CautionCaution: dirt sensitive area
Touching the product or parts thereof with barehands increases the desorption rate.
Always wear clean, lint-free gloves and use clean
tools when working in this area.
Small deposits on the electrode system can be removed bybaking the anode (Degas →  28). In the case of severe contamination, the baffle can be exchanged easily (→  19). The sensor itself cannot be cleaned and needs to be replaced in case of
severe contamination (→  42).

6.2

What to Do in Case of Problems
In the event of a fault or a complete failure of the output signal,
the gauge can easily be checked.

Required tools / material• Voltmeter / ohmmeter• Allen wrench, AF 2.5• Spare sensor (if the sensor is faulty)

tina92e1(2014-12)39

Trouble shooting (Gauge)
The output signal is available at the sensor cable connector(Pin 3).
In case of an error, it may be helpful to just turn off themains supply and turn it on again after 5 s.
ProblemPossible cause

Correction

Output signal
permanently≈0 V

Sensor cable defective or notcorrectly connected

Check the sensor cableNo supply voltage

Turn on the power supply: The
power supply indicator lit solid
green

Gauge in an undefined status

Turn the gauge off and on again(reset)EEPROM error

Turn the gauge off and on again
after 5 s
Replace the electronics unit

Hot cathode error (sensor
defective)

Replace the sensor (→  42)

Output signal>10 V→ also  25, filament status

Corrupted or no
output signal

40Electronics unit not mounted
correctly on sensor

Check the connections(electronics – sensor)

Emission is switched off

Turn on the emission only atpressures <2.7×10-2 mbar

Internal data connection notworking

Turn the gauge off and on again
after 5 s
Replace the electronics unit

tina92e1(2014-12)

Troubleshooting (sensor)
If the cause of a fault is suspected to be in the sensor, thefollowing checks can be made with an ohmmeter (the vacuum
system need not be vented for this purpose).
Separate the sensor from the electronics unit (→  18). Using anohmmeter, make the following measurements on the contactpins.

All unmarked pins in the diagram are used by the sensor
electronics and cannot be utilized for diagnostic purposes (do not connect an ohmmeter / continuity checker
to these pins).
Ohmmeter measurement between pins

Possible cause

6+7≈0.15 Ω>>0.15 Ω Filament 1 broken 12)

7+8≈0.15 Ω6/7/8 + 1∞

12)>>0.15 Ω Filament 2 broken
Electrode - short circuit to ground
<< ∞

3+1

∞

<< ∞

Electrode - short circuit to ground

9+1

∞

<< ∞

Electrode - short circuit to ground

6/7/8 + 3∞<< ∞Short circuit between electrodes

9+3

∞

<< ∞

Short circuit between electrodes

12)

tina92e1→ also "Filament Status",  25.

(2014-12)41

View on sensor pins
7
8

6

1
5
9
4

2
3

6
7
8
2
4
5
3
1
9

Hot cathode (FIL 1) appr. 0.15 Ohm
Hot cathode (FIL 2) appr. 0.15 Ohm
not used
not used
not used
Anode
GND (connected to sensor housing)Ion collector

Correction
All of the above faults can only be remedied by replacing thesensor (→  42).

6.3

Replacing the Sensor
Replacement is necessary, when
• the sensor is severely contaminated• the sensor is mechanically deformed• the sensor is faulty, e.g. one / both filaments of hot cathodebroken (→  39)
We recommend to replace the sensor as soon as thefirst filament failure has been detected (→  42).

42

tina92e1(2014-12)

Required tools / material• Allen wrench, AF 2.5• Spare sensor (→  46)

Procedure Deinstall the gauge (→  37).
 Deinstall the electronics unit from the faulty sensor andmount it to the new sensor (→  18).

tina92e1(2014-12)43

7Returning the Product
WARNINGWARNING: forwarding contaminated productsContaminated products (e.g. radioactive, toxic,
caustic or microbiological hazard) can be detrimental to health and environment.
Products returned to INFICON should preferably befree of harmful substances. Adhere to the forwarding regulations of all involved countries and forwarding companies and enclose a duly completed
declaration of contamination (form under
www.inficon.com).
Products that are not clearly declared as "free of harmful substances" are decontaminated at the expense of the customer.
Products not accompanied by a duly completed declaration ofcontamination are returned to the sender at his own expense.

44

tina92e1(2014-12)

8

Disposal
DANGERDANGER: contaminated parts
Contaminated parts can be detrimental to healthand environment.
Before beginning to work, find out whether any
parts are contaminated. Adhere to the relevant regulations and take the necessary precautions whenhandling contaminated parts.

WARNINGWARNING: substances detrimental to the environment
Products or parts thereof (mechanical and electriccomponents, operating fluids etc.) can be detrimental to the environment.
Dispose of such substances in accordance with therelevant local regulations.

Separating the components
After disassembling the product, separate its components according to the following criteria:• Contaminated components
Contaminated components (radioactive, toxic, caustic or biological hazard etc.) must be decontaminated in accordancewith the relevant national regulations, separated according totheir materials, and disposed of.
• Other components
Such components must be separated according to their materials and recycled.

tina92e1(2014-12)45

9Options

Baffle DN 25 ISO-KF / DN 40 CF-R (→  19)

10

Accessories

Communication adapter for diagnostic port
(1.9 m)11

Ordering No
353-512

Ordering No
303-333

Spare Parts
When ordering spare parts, always indicate:• all information on the product nameplate• description and part number

Replacement sensor BAG402, DN 25 ISO-KF(including allen wrench)
Replacement sensor BAG402, DN 40 CF-R
(including allen wrench)

46

Ordering No
354-484354-485

tina92e1(2014-12)

EC Declaration of Conformity
We, INFICON, hereby declare that the equipment mentioned
below complies with the provisions of the Directive relating toelectromagnetic compatibility 2014/30/EU and the Directive on
the restriction of the use of certain hazardous substances inelectrical and electronic equipment 2011/65/EU.

Bayard-Alpert Gauge
BAG402Standards
Harmonized and international / national standards and specifications:• EN 61010-1:2010 (Safety requirements for electrical equipment formeasurement, control and laboratory use)

• EN 61326-1:2013 (EMC requirements for electrical equipment formeasurement, control and laboratory use)

Manufacturer / Signatures
INFICON AG, Alte Landstraße 6, LI-9496 Balzers

tina92e1

27 October 2014

27 October 2014

Dr. Urs Wälchli
Managing Director

Marco Kern
Product Manager(2014-12)47

Original: German tina92d1 (2014-12)t i na92e1

LI–9496 Balzers
LiechtensteinTel +423 / 388 3111
Fax +423 / 388 3700
reachus@inficon.com
www.inficon.com