INFICON HPG400 ATM User Manual

Download

Operating Maual

High Pressure / Pirani Gauge

HPG400 HPG400-SD HPG400-SP

tina31e1 (2004-05) 1

Product Identification

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

INFICON AG, LI-949 6 Balzers

Typ: No: F-No: V W

Validity

This document applies to products with the following part numbers: HPG400

HPG400 (with display)

HPG400-SD (with DeviceNet interface and switching functions)

HPG400-SP (with Profibus interface and switching functions)

The part number (PN) can be taken from the product nameplate.

All HPG400 versions are shipped with an instruction sheet (→  [8]). HPG400-SD and HPG400-SP come with a supplementary instruction sheet de-

scribing the fieldbus interfaces and the switching functions (→  [9]).

(without display)

353-520 353-522 (vacuum connection DN 40 CF-R)

353-521 353-523 (vacuum connection DN 40 CF-R)

353-527 353-528 (vacuum connection DN 40 CF-R)

353-525 353-526 (vacuum connection DN 40 CF-R)

(vacuum connection DN 25 ISO-KF)

If not indicated otherwise in the legends, the illustrations in this document correspond to gauge with part number 353-520. They apply to the other gauges by analogy.

We reserve the right to make technical changes without prior notice.

2 tina31e1 (2004-05) HPG400 v1.om

Intended Use

The HPG400 gauges have been designed for vacuum measurement of non-flammable gases and gas mixtures in a pressure range of 2×10 trol range of the gauge allows trend display from <1 mbar to 1000 mbar.

The gauges can be operated in connection with the INFICON Vacuum Gauge Controller VGC4XX or with other control devices.

-6

… 1 mbar. The con-

Functional Principle

Trademarks

The HPG400 functions with a HP (high pressure) hot cathode ionization manometer, which is controlled by the built-in Pirani manometer (control range). The hot cathode is switched on only below the switching threshold of ≈1 mbar (to prevent filament burn-out). For pressures above this threshold, the Pirani signal is output.

Over the whole measuring range, the measuring signal is output as logarithm of the pressure.

DeviceNet™ Open DeviceNet Vendor Association, Inc.

tina31e1 (2004-05) HPG400 v1.om 3

Contents

Product Identification 2 Validity 2 Intended Use 3 Functional Principle 3 Trademarks 3

1 Safety 6

1.1 Symbols Used 6

1.2 Personnel Qualifications 6

1.3 General Safety Instructions 7

1.4 Liability and Warranty 7

2 Technical Data 8 3 Installation 13

3.1 Vacuum Connection 13

3.1.1 Removing and Installing the Electronics Unit 15

3.2 Electrical Connection 16

3.2.1 Use With INFICON VGC4XX Vacuum Gauge Controller 16

3.2.2 Use With Other Controllers 17

3.2.2.1 Making a Sensor Cable 17

3.2.2.2 Making a DeviceNet Interface Cable (HPG400-SD) 19

3.2.2.3 Making a Profibus Interface Cable (HPG400-SP) 20

3.2.3 Using the Optional Power Supply (With RS232C Line) 21

4 Operation 23

4.1 Measuring Principle, Measuring Behavior 23

4.2 Operational Principle of the Gauge 25

4.3 Putting the Gauge Into Operation 26

4.4 Display (HPG400) 27

4.5 RS232C Interface 28

4.5.1 Description of the Functions 28

4.5.1.1 Output String (Transmit) 28

4.5.1.2 Input String (Receive) 30

4.6 DeviceNet Interface (HPG400-SD) 31

4.6.1 Description of the Functions 31

4.6.2 Operating Parameters 31

4.6.2.1 Operating Software 31

4.6.2.2 Node Address Setting 31

4.6.2.3 Data Rate Setting 32

4.6.3 Status Lights 32

4.7 Profibus Interface (HPG400-SP) 33

4.7.1 Description of the Functions 33

4.7.2 Operating Parameters 33

4.7.2.1 Operating Software 33

4.7.2.2 Node Address Setting 33

4.8 Switching Functions (HPG400-SD, HPG400-SP) 34

4.8.1 Setting the Switching Functions 34

5 Deinstallation 36

4 tina31e1 (2004-05) HPG400 v1.om

6 Maintenance, Repair 37

6.1 Maintenance 37

6.2 Adjusting the Gauge 37

6.2.1 Pirani Adjustment (HPG400) 37

6.2.2 Pirani Adjustment (HPG400-SD, HPG400-SP) 38

6.3 Adjusting the Calibration Setting of the Hot Cathode 39

6.4 What to Do in Case of Problems 40

6.5 Replacing the Sensor 42

7 Options 43 8 Spare Parts 43 9 Storage 43 10 Returning the Product 44 11 Disposal 44

Appendix 45

A: Relationship Output Signal – Pressure 45 B: Gas Type Dependence 46 C: Literature 48

Declaration of Contamination 49

For cross-references within this document, the symbol (→  XY) is used, for crossreferences to other documents, the symbol (→  [Z]).

tina31e1 (2004-05) HPG400 v1.om 5

1 Safety

1.1 Symbols Used

DANGER

Information on preventing any kind of physical injury.

WARNING

Information on preventing extensive equipment and environmental damage.

Caution

Information on correct handling or use. Disregard can lead to malfunctions or minor equipment damage.

Notice

1.2 Personnel Qualifications

Hint, recommendation

The result is O.K.

The result is not as expected

Optical inspection

Waiting time, reaction time

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-user of the product.

6 tina31e1 (2004-05) HPG400 v1.om

1.3 General Safety Instructions

• Adhere to the applicable regulations and take the necessary precautions for the process media used.

Consider possible reactions between the materials (→  11) and the process media.

Consider possible reactions of the process media (e.g. explosion) due to 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 the safety 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 null and void if the enduser 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 corresponding product docu-

mentation.

The end-user assumes the responsibility in conjunction with the process media used.

tina31e1 (2004-05) HPG400 v1.om 7

2 Technical Data

Measurement

Emission

Measuring range (air, N2)

Hot cathode Pirani (control range)

Accuracy

-5

… 1 mbar

2×10 1×10

±15% of reading (valid between 10 over threshold setting (<P ↔ HP>, →  25).

Repeatability

-5

… 10-1 mbar

-1

… 100 mbar

Gas type dependence

Switching (changeover) threshold (selectable from 5 defined setpoints)

(after 10 min. stabilization) ±2% of reading

±30% of reading

→ Appendix B

1 mbar 5×10 2×10 1×10 5×10

Emission current

from 1 mbar to 2×10

–6

mbar

continually rising 4 µA 130 µA

Anode voltage 180 V

-6

… 1 mbar

-2

… 1000 mbar

–1

mbar

–1

mbar

–1

mbar

–2

mbar

-5

mbar and change-

Output signal

Identification of the gauge

Voltage range 0 … +10.2 VDC Measuring range

Hot cathode Pirani

Overrange hot cathode Underrange hot cathode

Overrange Pirani Underrange Pirani

Relationship voltage-pressure

Hot cathode Pirani

1.5 … 7.5 V

8.5 … 9.75 V

7.5 V ≤ U ≤ 8.0 V

0.5 V ≤ U ≤ 1.5 V

9.75 V ≤ U ≤ 10.2 V

8.0 V ≤ U ≤ 8.5 V logarithmic,

→ Appendix A

1.00 V/decade

0.25 V/decade

Error signals

Hot cathode error Pirani error

Min. load impedance

Resistor

≤+0.3 V, →  40 ≤+0.5 V, →  40

10 kΩ, short cicuit proof

56 kΩ between pin 10 and pin 5 (sensor cable connector)

8 tina31e1 (2004-05) HPG400 v1.om

Display (HPG400)

For gauges with part numbers

353-521 353-523

Power supply

Display panel

LCD matrix, 32×16 pixels, with background illumination green = normal operation

red = error/warning →  27) Dimensions Parameters

16.0 mm × 11.2 mm

Pressure, pressure unit, status,

error messages Pressure units

mbar (factory setting), Torr, Pa

(selecting the pressure unit →  28)

DANGER

The gauge must only be connected to power supplies, instruments or control devices that conform to the requirements of a grounded extralow voltage (SELV-E according to EN 61010). The connection to the gauge has to be fused (INFICON controllers fulfill these requirements).

Operating voltage at the gauge +24 VDC (20 … 28 VDC)

ripple max. 2 V

Power consumption

Standard Emission start (<200 ms)

≤0.5 A ≤1.4 A

Power consumption

HPG400, HPG400-SD HPG400-SP

≤16 W ≤18 W

Fuse necessary 1.25 AT

HPG400-SD requires an additional, separate power supply for the DeviceNet interface (→  19).

Supply voltage at the DeviceNet connector (Pin 2 and Pin 3) +24 VDC (+11 … 25 VDC)

Power consumption <2 W The gauge is protected against reversed polarity of the supply voltage.

Measured at sensor cable connector (consider the voltage drop as function of the sensor cable length).

tina31e1 (2004-05) HPG400 v1.om 9

Sensor cable connection

For reasons of compatibility, the expression "sensor cable" is used for all HPG400 versions in this document, although the pressure reading of the gauges with fieldbus interface (HPG400-SD and HPG400-SP) is normally transmitted via the corresponding bus.

Electrical connector

HPG400 HPG400-SD, HPG400-SP

Cable for HPG400

Analog values only Incl. RS232C interface and

identification

Cable for HPG400-SD, HPG400-SP

Max. cable length (supply voltage 24 V)

Analog and fieldbus operation

RS232C- and VGC4XX operation

Switching functions

HPG400 HPG400-SD, HPG400-SP

Adjustment range

Relay contact rating

Voltage Current

D-Sub,15 pins, male

→  17 →  18

4 conductors plus shielding

7 conductors plus shielding depending on the functions used,

max. 14 conductors plus shielding

≤35 m, conductor cross-section 0.25 mm² ≤50 m, conductor cross-section 0.34 mm ≤100 m, conductor cross-section 1.0 mm²

≤30 m

none 2 (Setpoint A and B)

-6

2×10

mbar … 100 mbar

Setpoints adjustable via potentiometers (setpoints A and B), one floating, normally open relay contact per setpoint (→  18, 34).

≤60 V ≤0.5 ADC

RS232C interface

DeviceNet interface (HPG400-SD)

Data rate Data format

9600 Baud binary

8 data bits one stop bit no parity bit no handshake

Connections (sensor cable connector)

TxD (Transmit Data) RxD (Receive Data) GND

Pin 13 Pin 14 Pin 5

Function and communication protocol of the RS232C interface →  28

For HPG400-SD gauges with part numbers:

353-527 353-528

Fieldbus name DeviceNet Standard applied Communication protocol, data format

→  [6] →  [1], [4]

Interface, physical CAN bus Data rate

(adjustable via "RATE" switch)

125, 250 and 500 kBaud "P" (125, 250 and 500 kBaud, programmable via DeviceNet (→  [1]))

Node address (MAC ID) (Adjustable via "ADDRESS", "MSD", "LSD" switches)

0 … 63

dec

"P" (programmable 0 … 63 via DeviceNet, →  [1])

10 tina31e1 (2004-05) HPG400 v1.om

DeviceNet connector Micro-Style, 5 pins, male

Cable Shielded, special DeviceNet cable,

5 conductors (→  19 and  [4])

Cable length, system wiring According to DeviceNet specifications

(→  [4], [6])

Profibus interface (HPG400-SP)

For HPG400-SP gauges with part numbers:

353-525 353-526

Fieldbus name Profibus Standard applied Communication protocol, data format

→  [7] →  [2], [7]

Interface, physical RS485 Data rate

≤12 MBaud (→  [2])

Node address

Local: (Adjustable via hexadecimal "ADDRESS", "MSD", "LSD" switches)

00 … 7D

(0 … 125

hex

dec

)

Via Profibus: (hexadecimal "ADDRESS" switches set to >7d

hex

(>125

dec

))

00 … 7D

(0 … 125

hex

dec

)

Profibus connection D-Sub, 9 pins, female

Cable Shielded, special Profibus cable

(→  20 and  [5])

Cable length, system wiring According to Profibus specifications

(→  [5], [7])

Vacuum

Environment

Materials exposed to vacuum

Housing, supports, screens Feedthroughs Insulator Cathode Cathode holder Pirani element

Internal volume

353-520, 353-521 353-525, 353-527

353-522, 353-523 353-526, 353-528

stainless steel

NiFe, nickel plated

glass

iridium, yttrium oxide (Y

molybdenum

tungsten, copper

≤20 cm

≤30 cm

≤30 cm Pressure max. 5 bar (absolut)

(only for Inert gases and

temperatures <100 °C).

Admissible temperatures

Storage Operation Bakeout

-20 … 70 °C 0 … 50 °C

+150 °C (without electronics unit)

Relative humidity (year's mean / during 60 days)

≤65 / 85% (no condensation)

Use indoors only

altitude up to 2000 m NN

Type of protection IP 30

2O3

)

tina31e1 (2004-05) HPG400 v1.om 11

Dimensions [mm]

Part numbers Part numbers 353-520 353-522 353-521 353-523 353-525 353-526 353-527

353-528

4-40UNC 2B

DN 25 ISO-KF

Gauges with DeviceNet connector are 14 mm longer. The other dimensions of housing and vacuum connection are identical.

Part numbers

353-527 353-528

4-40UNC 2B

DN 40 CF-R

Weight

353-520, 353-521 353-522, 353-523 353-525, 353-527 353-526, 353-528

12 tina31e1 (2004-05) HPG400 v1.om

285 g 550 g 430 g 695 g

3 Installation

3.1 Vacuum Connection

DANGER

Caution: overpressure in the vacuum system >1 bar Injury caused by released parts and harm caused by 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 of clamps which are suited to overpressure.

DANGER

Caution: overpressure in the vacuum system >2 bar KF flange connections with elastomer seals (e.g. O-rings) cannot

withstand such pressures. Process media can thus leak and possibly damage your health.

Use O-rings provided with an outer centering ring.

DANGER

The gauge must be electrically connected to the grounded vacuum 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 vacuum connection, use a conductive me-

tallic clamping ring.

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.

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. See dimensional drawing for space requirements(→  12).

• The gauge is supplied with a built-in baffle.

• The sensor can be baked at up to 150 °C. At temperatures exceeding 50 °C,

the electronics unit has to be removed (→  15).

tina31e1 (2004-05) HPG400 v1.om 13

Procedure

Remove the protective lid.



The protective lid will be needed for maintenance.

Make the flange connection to the vacuum system, preferably without ap-



plying vacuum grease.

When installing the gauge, make sure that the area around the connector is accessible for the tools required for adjustment while the gauge is mounted

When installing the gauge, allow for installing/deinstalling the connectors and accommodation of cable loops.

If you are using a gauge with display, make sure easy reading of the display is possible.

The gauge is now installed.

14 tina31e1 (2004-05) HPG400 v1.om

3.1.1 Removing and Installing the Electronics Unit

Required tools / material

Removing the electronics unit

• Allen key, size 2.5 mm

 Unscrew the hexagon socket set screw (1) on the side of the electronics

unit (2).

 Remove the electronics unit without twisting it.

Installing the electronics unit

Removal of the electronics unit is completed.

 Place the electronics unit on the sensor (3) (be careful to correctly align the

pins and notch (4)).

tina31e1 (2004-05) HPG400 v1.om 15

3.2 Electrical Connection

 Slide the electronics unit in to the mechanical stop and lock it with the hexa-

gon socket set screw (1).

The electronics unit is now installed.

3.2.1 Use With INFICON VGC4XX Vacuum Gauge Controller

Required material

Procedure

If the gauge is used with an INFICON VGC4XX controller, a corresponding sensor cable is required (→  43). The sensor cable permits supplying the gauge with power, transmitting measurement values and gauge statuses, and making parameter settings.

Caution

Caution: data transmission errors If the gauge is operated with the INFICON VGC4XX Vacuum Gauge

Controller (RS232C) and a fieldbus interface at the same time, data transmission errors may occur.

The gauge must not be operated with an INFICON VGC4XX controller and DeviceNet or Profibus at the same time.

• Sensor cable (→  [10] INFICON sales literature)

 Plug the sensor connector into the gauge and secure it with the locking

screws.

 Connect the other end of the sensor cable to the INFICON controller and

secure it.

The gauge can now be operated with the VGC4XX controller.

16 tina31e1 (2004-05) HPG400 v1.om

3.2.2 Use With Other Controllers

The gauge can also be operated with other controllers. Especially the fieldbus versions HPG400-SD (DeviceNet) and HPG400-SP

(Profibus) are usually operated as part of a network, controlled by a master or bus controller. In such cases, the control system has to be operated with the appropriate software and communication protocol (→  [1] and [2]).

3.2.2.1 Making a Sensor Cable

Cable type

Procedure

Sensor cable connection HPG400

For reasons of compatibility, the expression "sensor cable" is used for all HPG400 versions in this document, although the pressure reading of the gauges with fieldbus interface (HPG400-SD or HPG400-SP) is normally transmitted via DeviceNet or Profibus.

The sensor cable is required for supplying all HPG400 types with power. In connection with the gauges with fieldbus interface (HPG400-SD and HPG400-SP), it also permits access to the relay contacts of the switching functions (→  18, 34).

The application and length of the sensor cable have to be considered when determining the number and cross sections of the conductors (→  10).

 Open the cable connector (D-Sub, 15 pins, female).

 Prepare the cable and solder/crimp it to the connector as indicated in the

diagram of the gauge used:

HPG400

Measuring signal

TxD

RxD

56k

Ω

13 14

5 10 15

1.25AT

Identification

RS232C

24 V

Electrical connection Pin 2 Signal output (measuring signal)

Pin 5 Supply voltage common, GND Pin 8 Supply voltage Pin 10 Gauge identifcation Pin 12 Signal common, GND Pin 13 RS232C, TxD Pin 14 RS232C, RxD Pin 15 Shielding, housing, GND

Pins 1, 3, 4, 6, 7, 9 and 11 are not connected internally.

tina31e1 (2004-05) HPG400 v1.om 17

+24 VDC

0 … +10 V

D-Sub, 15 pins

soldering side

female

Sensor cable connection HPG400-SD, HPG400-SP

HPG400-SD, HPG400-SP

Threshold value, SP A Threshold value, SP B

SP A

3 6 1 4

SP B

TxD

RxD

Measuring

signal

56 k

Ω

13 14

10 15

7 8 2

RS232

1.25 AT 24V

Identification

Electrical connection Pin 1 Relay Switching function A, COM contact

Pin 2 Signal output (measuring signal) 0 … +10 V Pin 3 Threshold value (Setpoint) A 0 … +10 V Pin 4 Relay Switching function A, N.O. contact Pin 5 Supply common, GND Pin 6 Threshold value (Setpoint) B 0 … +10 V Pin 7 not connected Pin 8 Supply voltag e +24 V Pin 9 Relay Switching function B,

COM contact

Pin 10 Gauge identification Pin 11 Relay Switching function B,

N.O. contact

Pin 12 Signal common, GND Pin 13 RS232, TxD Pin 14 RS232, RxD Pin 15 Shielding, housing, GND

D-Sub, 15 pins

female

soldering side

WARNING

The supply common (Pin 5) and the shielding (Pin 15) must be connected at the supply unit with protective ground.

Incorrect connection, incorrect polarity or inadmissible supply voltages can damage the gauge.

For cable lengths up to 5 m (0.34 mm2 conductor cross-section) the output signal can be measured directly between the positive signal output (Pin 2) and supply common GND (Pin 5) without loss of accuracy. At greater cable lengths, differential measurement between signal output (Pin 2) and signal common (Pin 12) is recommended.

 Reassemble the cable connector.

 On the other cable end, terminate the cable according to the requirements

of the gauge controller you are using.

18 tina31e1 (2004-05) HPG400 v1.om

Plug the sensor connector into



the gauge and secure it with the locking screws.

 Connect the other end of the sensor cable to the connector of the instru-

ment or gauge controller you are using.

The gauge can now be operated via analog and RS232C interface.

3.2.2.2 Making a DeviceNet Interface Cable

(HPG400-SD)

Cable type

Procedure

For operating HPG400-SD via DeviceNet, an interface cable conforming to the DeviceNet standard is required.

If no such cable is available, make one according to the following indications.

A shielded special 5 conductor cable conforming to the DeviceNet standard has to be used (→  [4], [6]).

 Make the DeviceNet cable according to the following indications.

Micro-Style, 5 pins, (DeviceNet)

female, soldering side

Pin 1 Drain Pin 2 Supply +24 VDC (DeviceNet interface only) Pin 3 Supply common GND (DeviceNet interface only) Pin 4 CAN_H Pin 5 CAN_L

tina31e1 (2004-05) HPG400 v1.om 19

 Plug the DeviceNet (and sensor) cable connector into the gauge.

3.2.2.3 Making a Profibus Interface Cable

(HPG400-SP)

Sensor cable

DeviceNet cable

 Lock the DeviceNet (and sensor) cable connector.

The gauge can now be operated via DeviceNet interface (→  31).

For operating HPG400-SP via Profibus, an interface cable conforming to the Profibus standard is required.

If no such cable is available, make one according to the following indications.

Cable type

Procedure

Only a cable that is suited to Profibus operation may be used (→  [5], [7]).

 Make the Profibus interface cable according to the following indications.

1 5

D-Sub, 9 pins male, soldering side

6 9

Pin 1 Do not connect Pin 2 Do not connect Pin 3 RxD/TxD-P Pin 4 CNTR-P Pin 5 DGND Pin 6 VP Pin 7 Do not connect Pin 8 RxD/TxD-N Pin 9 Do not connect

Only to be connected if an optical link module is used.

Only required as line termination for devices at both ends of bus cable (→  [5]).

20 tina31e1 (2004-05) HPG400 v1.om

 Plug the Profibus (and sensor) cable connector into the gauge.

Sensor cable

Profibus cable

 Lock the Profibus (and sensor) cable connector.

The gauge can now be operated via Profibus interface (→  33).

3.2.3 Using the Optional Power Supply (With RS232C Line)

Technical data

The optional 24 V power supply (→  43) allows RS232C operation of the HPG400 gauge with any suitable instrument or control device (e.g. PC).

The instrument or control device needs to be equipped with a software that supports the RS232C protocol of the gauge (→  28).

Mains connection

Mains voltage 90 … 250 VAC 50 … 60 Hz Mains cable 1.8 meter

(Schuko DIN and U.S. connectors)

Output (operating voltage of gauge)

Voltage 21 … 27 VDC, set to 24 VDC Current max. 1.5 A

Gauge connection

Connector D-Sub, 15 pins, female 24 V cable 5 m, black

Connection of the instrument or control device

RS232C connection D-Sub, 9 pins, female Cable 5 m, black, 3 conductors, shielded

tina31e1 (2004-05) HPG400 v1.om 21

Wiring diagram

Connecting the power supply

8 7 6

RS232C

D-Sub, 9 pins

5 2 3

Mains

90 ... 250 VAC

50 ... 60 Hz

HPG400

D-Sub, 15 pins

5 13 14

8 15

+24 V

GND

 Connect the gauge to the power supply and lock the connector with the

screws.

 Connect the RS232C line to the instrument or control device and lock the

connector with the screws.

RS232C

Power supply

HPG400

 Connect the power supply to the mains.

 Turn the power supply on.

The gauge can now be operated via RS232C interface (→  28).

Mains

22 tina31e1 (2004-05) HPG400 v1.om

4 Operation

4.1 Measuring Principle, Measuring Behavior

High pressure (HP) hot cathode

The HPG400 consists of two separate measuring systems (high pressure (HP) hot cathode and Pirani).

The HP hot cathode measuring system is based on the electrode arrangement shown in the figure below, which grants sensitivity, linearity, and stability even at high pressures.

The measuring principle of this system is based on gas ionization. Electrons emitted by the hot cathode (F) ionize a number of molecules proportional to the pressure in the measuring chamber. The ion collector (IC) collects the thus generated ion current I The ion current is dependent on the emission current I

and feeds it to the electrometer amplifier of the measuring instrument.

, the gas type, and the gas

pressure p according to the following relationship:

= Ie × p × C

Factor C represents the sensitivity of the gauge. It is generally specified for N

-6

The lower measurement limit is 2×10 In order for the entire range of 2×10

current is continually increased from 4 µA at 1 mbar to 130 µA at 2×10

mbar.

-6

mbar … 1 mbar to be covered, the emission

-6

mbar (no

transients due to switching of the emission current).

IC ECF

Diagram of the HP measuring system

F hot cathode (filament) IC ion collector EC electron collector (anode)

ECIC

tina31e1 (2004-05) HPG400 v1.om 23

Pirani (control range)

Within certain limits, the thermal conductance of gases is pressure dependent. This physical phenomenon is used for pressure measurement in the thermal conductance vacuum meter according to Pirani. A self-adjusting bridge is used as measuring circuit. A thin tungsten wire is used as sensor element. Wire resistance and thus temperature are kept constant through a suitable control circuit. The electric power supplied to the wire is a measure for the thermal conductance and thus the gas pressure. The basic principle of the self adjusting bridge circuit is shown below.

–

Pirani sensor

The bridge voltage Um is a measure for the gas pressure and is further processed electronically (linearization, conversion).

Measuring range, changeover threshold

The HPG400 covers the measuring range 2×10

-6

... 1000 mbar.

Hot cathode HP Pirani

1000 mbar2 × 10-6 mbar

5×10-2 mbar ... 1 mbar user-

definable changeover threshold

• The Pirani permanently monitors the pressure.

• The hot cathode (controlled by the Pirani) is activated only at pressures

<1 ... 5×10

If the measured pressure is higher than the set changeover threshold (which can be selected with a switch within the range of 1 ... 5×10

-2

mbar (threshold can be set with a switch).

-2

mbar), the hot cathode

remains off and the Pirani value is output as signal (→ Appendix A). When the pressure measured by the Pirani drops below the threshold, the hot

cathode is activated. This is indicated by a green lamp. After warming up of the measuring system, the hot cathode value is output. When the pressure rises above the set threshold, the hot cathode is deactivated, and the Pirani value is output again.

24 tina31e1 (2004-05) HPG400 v1.om

4.2 Operational Principle of the Gauge

The measuring currents of the HP hot cathode and Pirani sensors are converted into a frequency. A micro controller converts this frequency into a digital value representing the measured total pressure. After further processing this value is available as analog measurement signal (0 … +10.2 V) at the output (sensor cable connector Pin 2 and Pin 12) with the usable ranges 1.5 … 7.5 V (hot cathode) and

8.5 … 9.75 V (Pirani). The maximum output signal is internally limited to +10.2 V (atmosphere). The measured value can be read as digital value through the RS232C interface (Pins 13, 14, 15) (→  28). Gauges with a display show the value as pressure. The default setting of the displayed pressure unit is mbar. It can be modified via the RS232C interface (→  28).

In addition to converting the output signal, the micro controller's functions include monitoring of the emission, calculation of the total pressure based on the measurements of the two sensors, and communication via RS232C interface.

Selecting the changeover threshold

The HPG400 has five definable changeover thresholds (setpoint "emission on"). It is thus possible to prevent the switching range from being situated within the process pressure range. The factory setting of the threshold is 1 mbar. Other setpoints can be selected via the <P ↔ HP> switch. Since the contamination of the hot cathode system is reduced at low pressures, the lowest possible setpoint should be selected.

Since the switch position is only polled upon activation of the gauge, the setpoint should be selected before the gauge is turned on.

EMI ON

Hot cathode mode

Pirani mode

Switch position

Corresponding setpoint

1 mbar (factory setting)

5×10 2×10 1×10 5×10

–1

mbar

–1

mbar

–1

mbar

–2

mbar

Accuracy

0 or 1 2 or 3 4 or 5 6 or 7 8 or 9

The gauge is factory-calibrated. Adjustment may become necessary due to use in different climatic conditions, extreme temperatures, contamination or aging (→  37).

-1

mbar and below

Gas type dependence

The accuracy is reduced in the pressure range above 1×10

-5

1×10

mbar.

The output signal is gas type dependent. The characteristic curves (→ Appendix A) are accurate for dry air, N

and O2. They can be mathematically converted for other

gases (→ Appendix B). If you are using a INFICON vacuum gauge controller, you can enter a calibration

factor to correct the displayed measured value (→  of the corresponding measurement unit).

tina31e1 (2004-05) HPG400 v1.om 25

Contamination

Gauge failures due to contamination are not covered by the warranty.

The HPG400 is designed in such a way that contamination by process products is minimal. The baffle and the closed internal design of the measuring system as well as the heat generated by the measuring system contribute to this.

The HPG400 is factory-adjusted in such a way that the hot cathode is switched on at ≈1 mbar. A lower threshold can be set in order for the contamination of the system to be reduced (→  25). The gauge can also be switched externally by the supply voltage, control by the Pirani still being insured.

In case of severe contamination, the measuring system should be replaced (→  42).

4.3 Putting the Gauge Into Operation

When the operating voltage is supplied (→ "Technical Data",  8 and "Electrical Connection",  16), the output signal is available between Pin 2 (+) and Pin 12 (–) of the sensor cable connector (Relationship Output Signal – Pressure → Appendix A).

Allow for a stabilizing time of approx. 10 min. Once the gauge has been switched on, permanently leave it on irrespective of the pressure.

Communication via the digital interfaces is described in separate sections.

26 tina31e1 (2004-05) HPG400 v1.om

4.4 Display (HPG400)

The gauges with part numbers

353-501 and 353-503

have a built-in two-line display with an LCD matrix of 32×16 pixels. The first line shows the pressure in normal operation, the second line the pressure unit, the function and operational status and possible error messages.

The background illumination is usually green, in the event of an error, it changes to red.

Pressure reading

Pressure display

Function display (status)

Pressure unit

Pressure reading in mbar (factory setting), Torr or Pa. The pressure unit can be changed via RS232C interface

(→  28).

==Emission of HP hot cathode on

Adjustment at atmospheric pressure in progress

= Normal operation, no error

(green background illumination)

Status

Error display

FAIL lonG 5 FAIL lonG 8 FAIL lonG 9

Internal data connection failure (red background illumination)

tina31e1 (2004-05) HPG400 v1.om 27

Pirani sensor warning

Hot cathode sensor warning

Pirani sensor error (red background illumination)

4.5 RS232C Interface

The built-in RS232C interface allows transmission of digital measurement data and instrument conditions as well as the setting of instrument parameters.

Caution

Caution: data transmission errors If the gauge is operated with the RS232C interface and a fieldbus in-

terface at the same time, data transmission errors may occur. The gauge must not be operated with the RS232C interface and

DeviceNet or Profibus at the same time.

4.5.1 Description of the

Functions

Operational parameters

Electrical connections

4.5.1.1 Output String (Transmit

Format of the output string

The interface works in duplex mode. A nine byte string is sent continuously without a request approx. every 20 ms.

Commands are transmitted to the gauge in a five byte input (receive) string.

• Data rate

• Byte

• TxD

• RxD

• GND

)

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

Byte No. Function Value

0 Length of data string 7 (Set value) 1 Page number 5 (Set value) 2 Status 3 Error 4 Measurement high byte 0 … 255 5 Measurement low byte 0 … 255 6 Software version 0 … 255 7 Sensor type 11 (For HPG400 gauges) 8 Check sum 0 … 255

9600 Baud set value, no handshake 8 data bits

1 stop bit

Pin 13 Pin 14 Pin 5 (Sensor cable connector)

→ Status byte → Error byte → Calculation of pressure value → Calculation of pressure value → Software version

→ Synchronization

Synchronization

28 tina31e1 (2004-05) HPG400 v1.om

Synchronization of the master is achieved by testing three bytes:

Byte No. Function Value Comment

0 Length of data string 7 (Set value) 1 Page number 5 (Set value) 8 Check sum of bytes No. 1 … 7 0 … 255 Low byte of

check sum

High order bytes are ignored in the check sum.

Status byte

Bit 1 Bit 0 Definition

0 0 Emission off 0 1 Emission on

Bit 2 Definition

0 1000 mbar adjustment off 1 1000 mbar adjustment on

Bit 3 Definition

0 ⇔ 1

Toggle bit, changes with every string received correctly

Bit 5 Bit 4 Definition

0 0 Current pressure unit mbar 0 1 Current pressure unit Torr 1 0 Current pressure unit Pa

Bit 7 Bit 6 Definition

x x Not used

Error byte

Software version

Calculation of the pressure value

Bit 3 Bit 2 Bit 1 Bit 0 Definition

x x x x Not used

Bit 7 Bit 6 Bit 5 Bit 4 Definition

0 1 0 1 Pirani adjusted poorly 1 0 0 0 Hot cathode error 1 0 0 1 Pirani error

The software version of the gauge can be calculated from the value of byte 6 of the transmitted string according to the following rule:

Version No. = Value

(Example: According to the above formula, Value

Byte 6

/ 20

of 32 means software ver-

Byte 6

sion 1.6)

The pressure can be calculated from bytes 4 and 5 of the transmitted string. Depending on the measuring range (hot cathode or Pirani) and 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. Measuring range hot cathode

(Range of values for byte 4 and 5 = 16666

p=10

(high Byte × 256 + low Byte) / 5333.3) - k1

… 48666

dec

)

Where Pressure unit k1

mbar 9.125 Torr 9.249903 Pa 7.125

Measuring range Pirani (Range of values for byte 4 and 5 = 54000

p=10

(high Byte × 256 + low Byte) / 1333.3) - k2

… 60666

dec

)

Where Pressure unit k2

mbar 42.5 Torr 42.624903 Pa 40.5

tina31e1 (2004-05) HPG400 v1.om 29

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 0 242 48 20 11 63 The instrument or controller (receiver) interprets this string as follows:

Byte No. Function Value Comment

0 Length of data

7 (Set value)

string 1 Page number 5 (Set value) 2 Status 0

Emission = off Pressure unit = mbar

3 Error 0

No error

Measurement 4 5

High byte Low byte

6 Software version 20

Calculation of the pressure:

235

(235 × 256 + 48) / 1333.3 - 42.5

p = 10 Software version = 20 / 20 = 1.0

= 454 mbar

7 Sensor type 11 (HPG400 gauges) 8 Check sum 63

5 + 0 + 0 + 235 + 48 + 20 + 11 =

01 3F

319

dec

hex

High order byte is ignored ⇒ Check sum = 3F

hex

dec

4.5.1.2 Input String (Receive)

Format of the input string

Admissible input strings

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

Byte No. Function Value

0 Length of data string 3 (Set value) 1 Data 2 Data 3 Data 4 Check sum

(from bytes No. 1 … 3) 0 … 255

High order bytes are ignored in the check sum.

→ admissible input strings → admissible input strings → admissible input strings

(low byte of sum)

For commands to the gauge, the following defined strings are used:

Byte No. Command 0 1 2 3 4 Set the unit mbar in the display 3 16 62 0 78 Set the unit Torr in the display 3 16 62 1 79 Set the unit Pa in the display 3 16 62 2 80 Power-failure-safe storage of current unit 3 32 62 62 156

Only low order byte of sum (high order byte is ignored).

30 tina31e1 (2004-05) HPG400 v1.om

4.6 DeviceNet Interface

(HPG400-SD)

This interface allows operation of HPG400-SD with part numbers

353-527 and 353-528

in connection with other devices that are suited for DeviceNet operation. The physical interface and communication firmware of HPG400-SD comply with the DeviceNet standard (→  [4], [6]).

Two adjustable switching functions are integrated in HPG400-SD. The corresponding relay contacts are available at the sensor cable connector (→  8, 18, 34).

The basic sensor and sensor electronics of all HPG400 gauges are identical.

Caution

Caution: data transmission errors If the gauge is operated via RS232C interface and DeviceNet interface

at the same time, data transmission errors may occur. The gauge must not be operated via RS232C interface and DeviceNet

interface at the same time.

4.6.1 Description of the Functions

4.6.2 Operating Parameters

4.6.2.1 Operating Software

4.6.2.2 Node Address Setting

Via this interface, the following and further data are exchanged in the standardized DeviceNet protocol (→  [1]):

• Pressure reading

• Pressure unit (Torr, mbar, Pa)

• Gauge adjustment

• Status and error messages

• Status of the switching functions

As the DeviceNet protocol is highly complex, the parameters and programming of HPG400-SD are described in detail in the separate Communication Protocol (→  [1]).

Before the gauge is put into operation, it has to be configured for DeviceNet operation. A configuration tool and the device specific EDS file (Electronic Data Sheet) are required for this purpose. The EDS file can be downloaded via internet (→  [3]).

For unambiguous identification of the gauge in a DeviceNet environment, a node address is required. The node address setting is made on the gauge or programmed via DeviceNet.

Set the node address (0 … 63 and "LSD" switches. The node address is polled by the firmware when the gauge is switched on. If the setting deviates from the stored value, the new value is taken over into the NVRAM. If a setting higher than 63 is made, the previous node address setting remains valid.

If the „MSD“ switch is in the "P" position, the node address is programmable via DeviceNet (→  [1]).

) via the "ADDRESS" "MSD"

dec

tina31e1 (2004-05) HPG400 v1.om 31

4.6.2.3 Data Rate Setting

The admissible data rate depends on a number of factors such as system parameters and cable length (→  [4], [6]) ]). It can be set on the gauge or programmed via DeviceNet.

By means of the "RATE" switch, the data rate can be set to 125 ("1"), 250 ("2") or 500 kBaud ("5").

If the switch is in any of the "P" positions, the data rate is programmable via DeviceNet (→  [1]).

4.6.3 Status Lights

"STATUS MOD" (gauge status)

"STATUS NET" (network status)

Two lights (LEDs) on the gauge inform on the gauge status and the current DeviceNet status.

Light status Description

Dark No supply

Flashing

red/green

Green Normal operation

Red Non recoverable error

Light status Description

Dark Gauge not online:

Flashing

green

Green Gauge online; necessary connections established

Flashing red One or several input/output connections in "timed out" status

Red Communication error. The gauge has detected an error that im-

Selftest

− Selftest not yet concluded

− No supply, → "STATUS MOD" light

Gauge online but no communication:

− Selftest concluded but no communication to other nodes established

− Gauge not assigned to any master

pedes communication via the network (e.g. two identical node addresses (MAC IC) or "Bus-off")

Electrical connections

32 tina31e1 (2004-05) HPG400 v1.om

The gauge is connected to the DeviceNet system via the 5-pin DeviceNet connector(→  19).

4.7 Profibus Interface

(HPG400-SP)

This interface allows operation of HPG400-SP with part numbers

353-525 and 353-526

in connection with other devices that are suited for Profibus operation. The physical interface and communication firmware of HPG400-SP comply with the Profibus standard (→  [5], [7]).

Two adjustable switching functions are integrated in the HPG400-SP. The corresponding relay contacts are available at the sensor cable connector (→  8, 18, 34).

The basic sensor and sensor electronics of all HPG400 gauges are identical.

Caution

Caution: data transmission errors If the gauge is operated via RS232C interface and Profibus interface at

the same time, data transmission errors may occur. The gauge must not be operated via RS232C interface and Profibus

interface at the same time.

4.7.1 Description of the Functions

4.7.2 Operating Parameters

4.7.2.1 Operating Software

4.7.2.2 Node Address Setting

Via this interface, the following and further data are exchanged in the standardized Profibus protocol (→  [2]):

• Pressure reading

• Pressure unit (Torr, mbar, Pa)

• Gauge adjustment

• Status and error messages

• Status of the switching functions

As the DeviceNet protocol is highly complex, the parameters and programming of HPG400-SP are described in detail in the separate Communication Protocol (→  [2]).

For operating the gauge via Profibus, prior installation of the HPG400 specific GSD file is required on the bus master side. This file can be downloaded via internet (→  [3]).

For unambiguous identification of the gauge in a Profibus environment, a node address is required. The node address setting is made on the gauge.

The node address (0 … 125 (00 … 7D

) via the "ADDRESS", "MSD", and "LSD" switches.

hex

) is set in hexadecimal form

dec

The node address is polled by the firmware when the gauge is switched on. If the setting deviates from the stored value, the new value is taken over into the NVRAM. If a value >7D (>125

) is entered, the node address setting currently stored in

dec

hex

the device remains valid but it can now be defined via Profibus ("Set slave Address", →  [2]).

Electrical connections

tina31e1 (2004-05) HPG400 v1.om 33

The gauge is connected to the Profibus via the 9-pin Profibus connector (→  20).

4.8 Switching Functions

(HPG400-SD, HPG400-SP)

The gauges HPG400-SD and HPG400-SP have two independent, manually adjustable switching functions. Each switching function has a floating normally open relay contact. The relay contacts are accessible at the sensor cable connector (→  18).

The threshold values of switching functions A and B can be set within the pressure range 1×10

-9

mbar … 100 mbar via potentiometers "SETPOINT A" and "SETPOINT B" (voltage settings representing pressures >100 mbar can be set, but the relay trigger point will remain at 100 mbar).

= 10 / 9 × (log p

Thresholdt

Setpoint

– c) + 6

Where U p c

[V] [mbar] 0 [V] [Pa] 2 [V] [Torr] -0.125

(→ Appendix A).

Measuring signal

(Pressure p)

Hysteresis 10% U

Threshold

(Setpoint A, B)

Switching function

Off

Threshold

Time t

4.8.1 Setting the Switching Functions

Required tools

The hysteresis of the switching functions is 10% of the threshold setting.

The threshold values of the two switching functions "SETPOINT A" and "SETPOINT B" are set locally on the potentiometers of the gauge that are accessible via the openings on one side of the gauge housing.

• Voltmeter

• Ohmmeter or continuity checker

• Screwdriver, max. ø2.5 mm

34 tina31e1 (2004-05) HPG400 v1.om

Procedure

The procedure for setting thresholds is identical for both switching functions.

 Put the gauge into operation.

 Connect the + lead of a voltmeter to the threshold measurement point of the

selected switching function ("Setpoint A" Pin 3, "Setpoint B" Pin 6) and its – lead to Pin 5.

max. ø2.5

Setpoint A Pin 3 Setpoint

Pin 6

Pin 5

 Using a screwdriver (max. ø2.5 mm), set the voltage of the selected

switching function (Setpoint A, B) to the desired value U

Setting of the switching functions is now concluded.

Threshold

There is no local visual indication of the statuses of the switching functions. However, a functional check of the switching functions (On/Off) can be made with one of the following methods:

• Reading the status via fieldbus interface (→  [1] for HPG400-SD, →  [2] for HPG400-SP).

• Measurement of the relay contacts at the sensor cable connector

with a ohmmeter/continuity checker (→  18).

tina31e1 (2004-05) HPG400 v1.om 35

5 Deinstallation

Procedure

DANGER

Caution: contaminated parts Contaminated parts can be detrimental to health and 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.

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.

 Vent the vacuum system.

Before taking the gauge out of operation, make sure that this has no adverse effect on the vacuum system.

Depending on the programming of the superset controller, faults may occur or error messages may be triggered.

Follow the appropriate shut-down and starting procedures.

 Take gauge out of operation.

 Disconnect all cables from the gauge.

 Remove gauge from the vacuum system and replace the protective lid.

The gauge is now deinstalled.

36 tina31e1 (2004-05) HPG400 v1.om

6 Maintenance, Repair

6.1 Maintenance

6.2 Adjusting the Gauge

DANGER

Caution: contaminated parts Contaminated parts can be detrimental to health and 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.

The gauge is factory-calibrated. Through the use in different climatic conditions, fitting positions, aging or contamination and after exchanging the sensor (→  42) a shifting of the characteristic curve can occur and readjustment can become necessary. Only the Pirani part can be adjusted.

Adjustment is necessary if

• at atmospheric pressure, the output signal is <9.75 V or the display reads < atmospheric pressure.

• when the vacuum system is vented, the output voltage reaches 9.75 V the measured pressure has reached atmospheric pressure (gauges with display will show the error "5" at atmospheric pressure (Pirani sensor warning →  27).

• at atmospheric pressure, the digital value of the RS232C interface is < atmospheric pressure.

• at atmospheric pressure, the digital value received by the bus controller of the fieldbus gauges (DeviceNet or Profibus) is < atmospheric pressure.

• when the vacuum system is vented, the digital value of the RS232C interface reaches its maximum before the measured pressure has reached atmospheric pressure.

• when the vacuum system is vented, the digital value received by the bus controller of the fieldbus (DeviceNet or Profibus) reaches its maximum before the measured pressure has reached atmospheric pressure.

The output signal is internally limited to +10.2 V.

before

Adjustment procedures for HPG400-SD/-SP and HPG400 gauges differ and will be described separately.

6.2.1 Pirani Adjustment (HPG400)

Required tools

HV adjustment Pirani

tina31e1 (2004-05) HPG400 v1.om 37

The following procedures are described:

• HV adjustment Pirani

• ATM adjustment Pirani

• Pin approx. ø1.3 × 50 mm (e.g. a bent open paper clip)

The Pirani part is automatically adjusted by the hot cathode part when the gauge is activated and a pressure value of 1 … 3×10

-3

mbar is reached for the first time.

Pirani adjustment at atmospheric pressure

 Put the gauge into operation.

Operate the gauge for ≈10 minutes at atmospheric pressure. If the gauge was operated within the hot cathode range, a coolingdown time of ≈30 minutes is to be expected (gauge temperature = environmental temperature).

 Adjust the gauge:

HPG400 without display

353-520, 353-522

Insert a pin (≈ø1.3×50mm) through the opening <FULL SCALE> and

push the button inside for at least 5 seconds.

HPG400 with display

353-521, 353-523

6.2.2 Pirani Adjustment (HPG400-SD, HPG400-SP)

Required tools

HV adjustment Pirani

Automatic adjustment in progress (≈10 s).

Adjustment completed.

The following procedures are described:

• HV adjustment Pirani

• ATM adjustment Pirani

• Pin, approx. ø1.3 × 50 mm (e.g. abent open paper clip)

The Pirani part is automatically adjusted by the hot cathode part when the gauge is activated and a pressure value of 1 … 3×10

-3

mbar is reached for the first time.

38 tina31e1 (2004-05) HPG400 v1.om

Pirani adjustment at atmospheric pressure

 Put the gauge into operation.

 Insert the pin through the opening marked <FULL SCALE> and push the

button inside for at least 5 seconds.

max. ø1.3

6.3 Adjusting the Calibration Setting of the Hot Cathode

The gauge is automatically adjusted (≈10 s).

The gauge is now adjusted at atmospheric pressure.

The sensor is factory calibrated. The calibration setting of the hot cathode range 0 … F is printed on the label. Correct this value with the <Cal adj> switch to adjust the electronics to the sensor. Before operating the gauge for the first time or after replacing the sensor, check the calibration value setting and adjust it if necessary.

tina31e1 (2004-05) HPG400 v1.om 39

6.4 What to Do in Case of Problems

Required tools / material

In the event of a fault or a complete failure of the output signal, the gauge can easily be checked.

• Voltmeter / ohmmeter

• Allen key, size 2.5 mm

• Spare sensor (if the sensor is faulty)

Troubleshooting

The output signal is available at the sensor cable connector (Pin 2 and Pin 12).

In case of an error, it may be helpful to just turn off the supply voltage and turn it on again after 5 seconds.

Problem Possible cause Correction Output signal

permanently ≈0V

Output signal ≈0.3 V (Display: error = 8)

Output signal ≈0.5 V (Display: error = 9)

Display: Internal data connection

Sensor cable defective or not correctly connected

No supply voltage Turn on the power supply Gauge in an undefined

status Hot cathode error

(sensor faulty) Pirani error

(sensor defective) Electronics unit not

mounted correctly on sensor

not working

Check the sensor cable

Turn the gauge off and on again (reset)

Replace the sensor (→  42)

Check the connection

Turn the gauge off and on again after 5 s

Replace the electronics unit

40 tina31e1 (2004-05) HPG400 v1.om

Troubleshooting (sensor)

If the cause of a fault is suspected to be in the sensor, the following checks can be made with an ohmmeter (the vacuum system need not be vented for this purpose).

Separate the sensor from the electronics unit (→  15). Using an ohmmeter, make the following measurements on the contact pins..

Ohmmeter measure-

ment between pins

4 + 5 5 + 8

1 + 2/6 2 + sensor housing 3 + sensor housing 5 + sensor housing 9 + sensor housing

2 + 3 2 + 9 3 + 9 2 + 5 3 + 5 5 + 9

View on sensor pins

≈37 Ω >>37 Ω ≈37 Ω >>37 Ω

≈0.2 Ω >>0.2 Ω

∞ << ∞ ∞ << ∞ << ∞ << ∞ << ∞ << ∞ << ∞ << ∞ << ∞ <<

1 2 6 3

7 9 4 5 8

Possible cause

Pirani element 1 broken Pirani element 2 broken Filament of hot cathode broken Short circuit electrode to ground Short circuit electrode to ground

∞

Short circuit electrode to ground

∞

Short circuit electrode to ground

∞