Ulvac G-Tran Series User manual

No. SK00-8431-EI-023-04
G-TRAN SERIES
SENSOR UNIT
MODEL SC1 COLD-CATHODE ION GAUGE
INSTRUCTION MANUAL
This manual is for the SC1 cold-cathode ion gauges
of the following serial numbers.
Serial No. 02300G and higher
Read this manual before operation and keep it at
hand for immediate reference.
Components Division,
ULVAC , Inc.
http://www.ulvac.co.jp/

I
Prior to Operation
Upon receipt of this gauge, make sure that it is the correct model you ordered and that it is
not damaged in transit.
Read this instruction manual before installing, operating,
inspecting, or maintaining the product and fully understand the safety
precautions, specifications and operating procedures regarding the
product.
The copyright of this instruction manual is held by ULVAC, Inc.
You are prohibited from copying any portion of this instruction
manual without the consent of ULVAC Inc.
You are also prohibited from disclosing or transferring this instruction
manual to third parties without the express written consent of
ULVAC Inc.
The contents described in this instruction manual are subject to
change without prior notice because of changes in specifications or
because of product improvements.
Safety Denotations
Safety symbols are used throughout this instruction manual to call
the operator's attention to safety. The terminology used in safety
symbols is classified below.
Indicate status of urgency of danger when failure to comply with
DANGER results in serious personal injury or death
The work ignoring this warning will lead to serious damage to
human life or factory facility (including this equipment) at a high
probability.
Indicate status of danger when failure to comply with WARNING
results in serious worker’s injury or death.
The work ignoring this warning will cause possibility leading to
serious damage to human life or factory facility (including this
equipment)
Indicate status of danger when failure to comply with WARNING
results in minor injury or moderate damage.
The work ignoring this warning will cause possibility leading to
minor damage to worker or breakage to equipment or necessary to
adjust.
Direct hazard is not existed, describe the necessity to know
from the viewpoint of worker’s safety or correct and safe operation of
equipment
✔Note

II
Safety Precautions
For safe use of this vacuum gauge, carefully read this manual and comply with the safety
precautions given in this manual.
Repair
Request repairs for this unit from the dealer where purchased, from
ULVAC Inc., or from the URL listed in this instruction manual.
Power off
If this unit is accidentally damaged, immediately turn off the power
supply. There is a risk of fire and electric shock from use in this state.
Power off
If this unit produces unusual heat, smoke, or a strange smell,
immediately turn off the power supply. There is a risk of fire from use
in this state.
Turn off power.
Turn off the power to the vacuum gauge before conducting
maintenance. The anode of the sensor head is energized with a voltage
of 2.6 kV DC. You may receive electric shock if you touch it.
Protective grounding
Always connect this unit electrically to a grounded vacuum chamber.
Use a conductive metal clamp on the NW flange. If this unit is not
correctly connected, it will not only show the wrong pressure, there is a
risk of damage to this unit and the equipment connected to this unit
and a risk of fire.
When this unit is insulated from the vacuum chamber, ground the case
section (D-sub connector shell section) with a class D (class 3) ground.
Don't disassemble.
Do not disassemble the vacuum gauge.
Don't modify.
Do not modify the vacuum gauge. If it is modified, its functions are
not warranted. Also fire or electric shock may result.
Operating environment
Do not connect the sensor head to a test object in which pressure is in
excess of atmospheric pressure. If the pres
sure in the sensor head
exceeds atmospheric pressure, the sensor head will be damaged or it
will pop out from the connector, causing injury to the surrounding,
includ
ing human body. If the pressure exceeds atmospheric pressure,
provide an isolation valve so that the pressure in the sensor head does
not exceed atmospheric pressure.
Use in a corrosive gas atmosphere
If this unit is exposed to chemically active gases including corrosive
gases and halogen or halogenated gases, problems will occur such as
pressure characteristics changing. When using this unit in these types
of environments, install an isolation valve between this unit and the
vacuum chamber and protect this unit as much as possible so it is not
exposed to these gases.

III
Use in a CVD gas atmosphere
If this unit is exposed to gases that deposit materials including CVD
(Chemical Vapor Deposition) material gases and rotary pump oil mist,
problems will occur such as pressure characteristics changing. When
using this unit in these types of environments, install an isolation valve
between this unit and the vacuum chamber and protect this unit so it
is not exposed to these gases.
Moisture and fouling
If there
is a large quantity of fouling in the gauge head from the
gradual vaporization of moisture or organic matter, pressure accuracy
and response speed will be affected. Review installation locations and
methods so that fouling does not occur.
Gas type dependency
The pressure value and accuracy for this unit differ by the type of gas
measured. The accuracy for this unit is based on measuring nitrogen
gas. Be careful when using gases other than nitrogen.
Check line voltage.
Prior to turning ON the powe
r, make sure that the vacuum gauge
operating voltage and the supply voltage are in agreement.
Connection of incorrect power can damage the vacuum gauge and cause
fire.
Shut off power
If there is a possibility of the operator touching the anode terminal of
the sensor head during operation, shut off the power. The anode
terminal of the sensor head is energized with a discharge voltage of 2.6
kV DC. If you touch it when this gauge is actuated, you will get electric
shock.
Operating environment
Do not use the gauge in a place where it may be splashed with water.
If wetted, it may fail or electric leak or fire can result.
Keep out foreign matter.
If foreign matter like metal fragments or combustibles are admitted
into the vacuum gauge through the openings in the gauge, remove
them. Also keep intact the connecting terminals at the top of the
gauge. Otherwise, the vacuum gauge may be damaged.
Beware of magnetic field
The magnetic flux density at the center of the sensor head is about 0.1
T. It will be attracted by or attract a metal part nearby with high
magnetic force. Be careful in maintenance that a screwdriver or a metal
part will be attracted with high magnetic force.
Check connection.
See to it that the power cable does not come into contact with other
conducting parts.
Discarding
When you discard a vacuum gauge, please process according to the
regulations of each local government. Especially the sensor head that
used it in
the atmosphere which may exert danger on a human body
needs to process through a special processing contractor.
Operating conditions
Use this vacuum gauge in the environment set forth by the
specifications.
Repacking for transfer
If the vacuum gauge
is to be shipped to other site, repack it in the same
way as on delivery. If the gauge is shipped bare, it may be damaged.

IV
Warning for Air transportation Packaging
The sensor for this product contains strong magnetic material.
Therefore, please seal the interior of the packaging material with metal
plate (more than 0.5mm thickness).
The magnetic force from the item packaged by above method is less
than .418A/m(0.00525gauss) at 4.6m distance from any given point, or
less than 0.159A/m(0.002gauss) at 2.1m distance from any given point,
qualifying IATA packaging standard 902 or UN-2807.
Wear clean gloves.
Handle the internal electrode with clean gloves. If the internal
electrode is stained with oil or contaminant, the pressure indication
may be affected by outgas.
Impact to the anode pin and glass part.
Such an impact may cause leak. Do not bend the anode pin nor give an
impact to the black glass portion.
Do not polish the glass portion of the anode.
Polishing can cause leak. Polish the pin using care not to apply load on
the glass portion.
Insulation resistance of anode
The pressure indication may be abnormal (higher than actual or no
change of indication) or components may fail if the insulation resistance
of the anode is not higher than 10,000 MΩ.
Check center axis of anode
After reassembly, make sure that the anode pin is at the center of the
magnetic pole 2. There is a possibility of contact with the magnetic pole
or low pressure indication.
Scar and dust on O-ring and O-ring groove
These can cause leak. Make sure that the O-rings and the O-ring
groove are free of scars and dust.
Dry parts
After cleaning, dry up electrode parts. If they are not dry, components
may be damaged by poor insulation.
Do not touch the sensor head
Do not touch the sensor head and anode during insulation resistance
check. If the anode and sensor head body are shorted, a high voltage of
2.6 V DC will be applied to the sensor head.
Do not conduct inspection in combustible gas atmosphere.
When turning on the high voltage to this gauge under atmospheric
pressure, avoid a combustible gas atmosphere. If a higher voltage of
about 2.6 kV DC is applied, sparks will be produced and may cause fire.
Maintenance
Aluminum electrolytic capacitor is used in the electric circuit of this
instrument. The life of the aluminum electrolytic capacitor becomes
shorter with increase of the ambient temperature, To prevent devices
from being damaged, it is recommended to conduct maintenance about
once every 3 years.

V
Revision History
DATE
No.
Description
Jun. 20, 2007
00
1st version
Aug.19, 2008
01
・
P.
Ⅳ
Added electrolytic capacitor life and Maintenance
・Section 3 Key specifications: change Output 5mA→ 50mA
・Section 3.4: Added Service Parts List
・Section 4.3: Change I/O Connector 12-pin→NC
・Section 5.2.3: Correction of Fig. 5-2
・Section 7: Correction of I/O signal explanations and diagrams
・
Section 9.1.1: Correction of Setpoint 5mA→50mA
Apr. 5, 2010
02
・
P.
Ⅳ
Added a caution
・Section 1.1: Change Overview
・Section 13: Added Certificate of Contamination
・
Delete all page headers
Feb. 8, 2013
03
・
Section 1.1: Change Overview
・Section 3.1: Added explanation of scale factor 2
・Section 3.3: Added ISG1 to the Display
・Section 7: Added a note on contact leak current
・Section 9.2: Added a note
・Section 10: Correction of cautions
・Section 12: Change warranty
・Section 13: Revision of pollution certificate
・
Section 15: Added Torr
Dec. 2, 2019 06 ・
Added Picture of SC1
・Added Revision History
・Section1.1. Delete Revised Overview of G-TRANS Series.
・Section 3.2, Do not attach
instruction manuals from standard
accessories.
・Section 3.3, Added option.
・Section 3.4, Correction of Service parts name.
・
Fig15-4, Correction of Display Unit

VI
Contents
Page
Prior to Operation I
Safety Denotations I
Safety Precautions II
Revision History Ⅴ
Contents Ⅵ
Attached Drawings Ⅷ
1. TERMINOLOGY ...........................エラー! ブックマークが定義されていません。
2. FEATURES OF SC1 Ion Gauge.............................................................................1
3. SPECIFICATIONS AND COMPONENTS............................................................2
3.1. Key Specifications........................................................................................................ 2
3.2. Standard Accessories................................................................................................... 3
3.3. Options ......................................................................................................................... 3
3.4. Service Parts ................................................................................................................ 3
4. NOMENCLATURE AND FUNCTIONS OF COMPONENTS.............................4
4.1. Assembly ...................................................................................................................... 4
4.2. Front Panel .................................................................................................................. 5
4.3. Input/Output Connector.............................................................................................. 6
5. INSTALLATION .....................................................................................................7
5.1. Preparations................................................................................................................. 7
5.2. Installation................................................................................................................... 7
5.2.1. Installing the sensor head to the sensor unit.................................................. 7
5.2.2. Installing the sensor unit.................................................................................. 7
5.2.3. Electrical connection.......................................................................................... 8
6. CAUTIONS IN HANDLING ..................................................................................9
7. OUTPUT SIGNALS ..............................................................................................10
7.1. Control Operation.................................................................................................... 100
7.1.1. High Voltage ON/OFF [HV ON/OFF] .......................................................... 100
7.2. Output Signals......................................................................................................... 100
7.2.1. Setpoint actuating signal [SET-1 ON/OFF][SET-2 ON/OFF] .................... 100
7.2.2. Discharge valid signal [Discharge OK/NG] ................................................. 100
8. SETTING OF SETPOINT ..................................................................................111
9. FUNCTIONS .......................................................................................................122
9.1. Setpoint [SET-1 ON/OFF] [SET-2 ON/OFF] ......................................................... 122
9.1.1. Setpoint........................................................................................................... 122
9.1.2. Setting of setpoint.......................................................................................... 122
9.1.3. Setpoints of measuring unit and display unit ............................................. 122
9.2. Measurement Value Output................................................................................... 133
9.2.1. Measurement value voltage output form..................................................... 133
9.2.2. Measurement value outputs in each condition............................................ 144
10. MAINTENANCE.................................................................................................155
10.1. Preparation of Tools and Others ............................................................................ 155
10.2. Necessary Tools and Others ................................................................................... 155
10.3. Necessary Equipment ............................................................................................. 155
10.4. Removing the Sensor Unit and Sensor Head ........................................................ 166
10.4.1. Removing Screws........................................................................................... 166
10.4.2. Removing the Sensor Head........................................................................... 166
10.5. Disassembling the Sensor Head............................................................................. 177

VII
10.5.1. Exploded View of Sensor Head ..................................................................... 177
10.5.2. Removing the Internal Electrode.................................................................. 188
10.6. Cleaning the Electrode in the Sensor Head........................................................... 211
10.6.1. Insulation Check of Anode ............................................................................ 211
10.6.2. Cleaning the Anode........................................................................................ 211
10.6.3. Cleaning Magnetic Poles 1 and 2.................................................................. 222
10.6.4. Cleaning the Spacer....................................................................................... 233
10.6.5. Cleaning the main body................................................................................. 244
10.6.6. Cleaning the O-ring and O-ring Groove....................................................... 244
10.6.7. Cleaning Parts ............................................................................................... 244
10.7. Reassembling the Sensor Head .............................................................................. 255
10.7.1. Reassembly..................................................................................................... 255
10.7.2. Checking the Anode Position ........................................................................ 255
10.8. Insulation Check...................................................................................................... 266
10.8.1. When a insulation resistance tester is available at hand........................... 266
10.8.2. If a insulation resistance tester is not available at Hand........................... 266
10.9. Leak Test.................................................................................................................. 288
10.10. Installing the Sensor Unit and Sensor Head...................................................... 29
10.11. Maintenance.......................................................................................................... 29
11. TROUBLESHOOTING .......................................................................................300
12. WARRANTY ........................................................................................................322
13. Certificate of Contamination..............................................................................333
14. China RoHS Declaration.....................................................................................344
15. APPENDIX ..........................................................................................................355
15.1. Pressure-Measurement Value Voltage Table (Pa) ................................................ 355
15.2. Pressure-Measurement Value Voltage Table (Torr)............................................. 388
15.3. Related Drawings .................................................................................................... 411
15.3.1. Compatible Sensor Heads ............................................................................. 411

VIII
Attached Drawings
Page
Fig. 4-1 Assembly ................................................................................................................4
Fig. 4-2 Front panel.............................................................................................................5
Fig. 4-3 Input/output connector pin assignment...............................................................6
Fig. 5-1 Installing SC1........................................................................................................7
Fig. 5-2 Equivalent circuit in the power supply................................................................8
Fig. 7-1 Signal input internal circuit diagram..............................................................100
Fig. 7-2 Signal output internal circuit diagram............................................................100
Fig. 9-1 Pressure-measurement value output graph (Pa)............................................133
Fig. 9-2 Pressure-measurement value output graph (Torr).........................................144
Fig. 10-1 Bottom view of sensor unit .............................................................................166
Fig. 10-2 Sensor head and sensor unit...........................................................................166
Fig. 10-3 Exploded view of sensor head.........................................................................177
Fig. 10-4 Removing the cap screw..................................................................................188
Fig. 10-5 Removing the cap screw..................................................................................188
Fig. 10-6 Removing the anode ..........................................................................................19
Fig. 10-7 Removing the O-ring .........................................................................................19
Fig. 10-8 Magnetic pole 1, spacer and magnetic pole 2 pushed out.............................200
Fig. 10-9 Insulation check of anode................................................................................211
Fig. 10-10 Anode..............................................................................................................211
Fig. 10-11 Polishing the anode (example)......................................................................222
Fig. 10-12 Magnetic poles ...............................................................................................222
Fig. 10-13 Magnetic poles 1 and 2 before and after polishing .....................................222
Fig. 10-14 Spacer .............................................................................................................233
Fig. 10-15 Spacer before and after polishing (example) ...............................................233
Fig. 10-16 Rounding the spacer......................................................................................233
Fig. 10-17 Inside view .....................................................................................................244
Fig. 10-18 O-ring and O-ring groove..............................................................................244
Fig. 10-19 Anode position after reassembly ..................................................................255
Fig. 10-20 Insulation check.............................................................................................266
Fig. 10-21 Check with the sensor unit connected .........................................................277
Fig. 10-22 Check with the sensor unit connected (wiring example)............................277
Fig. 10-23 Leak check position.......................................................................................288
Fig. 10-24 Installing the sensor unit and sensor head ...................................................29
Fig. 10-25 Maintenance kit...............................................................................................29
Fig. 15-1 Compatible sensor heads ................................................................................411
Fig. 15-2 Dimensional drawing ......................................................................................422
Fig. 15-3 Connection reference drawing (1)...................................................................433
Fig. 15-4 Connection reference diagram (2) ..................................................................444

1
1. TERMINOLOGY
In this manual, the following terms have the same meanings.
Setpoint
SETPOINT
SET
High voltage
High Voltage
H. V.
Pressure protection (signal)
PROTECT
PRT
Communication mode
Remote mode
RS-MODE
CAL function
CALCULATING FUNCTION
CAL
2. FEATURES OF SC1 Ion Gauge
• This gauge is a inverted magnetron type vacuum gauge having a wider measurable
pressure range than the conventional Penning vacuum gauge.
• The measurable pressure range is 1.0 ×10-5 Pa to 1 Pa, 7.5×10-8 Torr to 7.5×10-3 Torr.
• The sensor head and the main unit are integrated in one unit.
• Simple structure having only a measuring section. Best suited to applications that
require no indicators only if data and signals can be taken out.
• Dedicated indicators (digital) are available as option.
• The gauge has independent setpoints (two).
• Small in size and does not take up much space for installation.
* Note the following differences depending on serial number.
Serial No.
Analog output value
when discharge is OFF
Discharge ON/OFF
signal
Software version
compatible with
4CH display
00001 and
higher
0 V
None
Ver. 2.14 and lower
00021 and
higher
10 V
None
Ver. 2.14 and lower
00031 and
higher
10 V
Available
Ver. 2.15 and
higher

2
3. SPECIFICATIONS AND COMPONENTS
3.1. Key Specifications
Name
Inverted magnetron type vacuum gauge Model SC1
Connectable sensor head
One pc.
Compatible sensor head
C-21, C-23, C-24, C-25
Measurable pressure range
1.0 ×10
-5
to 1 Pa, 7.5×10
-8
Torr to 7.5×10
-3
Torr
Measurement accuracy (N2)
(when shipped from factory)
Scale factor 2
*:Scale factor 2: -50% to +100%
Applied voltage
Approx. 2.6 kVDC
Operating temperature range
10 to 40°C
Control input signal
HV ON/OFF
Data output
0 V to 10 VDC, non-linear
Measurement data
Setpoint actuating set value 1: data
Setpoint actuating set value 2: data
Control output signal Open collector output, negative logic
[24 VMAX, 50 mAMAX, saturation voltage is 1V]
Setpoint actuating signal -1 [ON/OFF]
Setpoint actuating signal -2 [ON/OFF]
Discharge confirm signal [OK/NG]
LED display
POWER
SET-1
ERROR
SET-2
Power supply
24 VDC ± 2 V, 150 mA (sensor unit alone)
Input/output connector
D-sub 15-pin (M2.6 screw)
Weight of main unit
430 g (not including sensor head)
Outside dimensions
See Fig. 15-1 Dimensional Drawing.

3
3.2. Standard Accessories
Connector
D-sub 15 socket (M2.6 screw)
1 pc.
Clamp hood
1 pc.
3.3. Options
Display unit
Digital
Model IM1R1 (24VDC power supply type)
Model IM2R1 (100VAC power supply type)
Model ISG1 (24VDC power supply type)
Sensor head
See 3.1 Key Specifications "Compatible Sensor Head".
Display cable
2 m, 5 m, and 10 m
(between measuring unit and display unit)
Test results certificate
Calibration certificate
Calibration certificate, JCSS Calibration certificate
3.4. Service Parts
Anode (SC1)
Cathode (SC1)
Magnetic pole-1, Magnetic pole-2, Spacer

4
4. NOMENCLATURE AND FUNCTIONS OF COMPONENTS
4.1. Assembly
Fig. 4-1 Assembly
No. Component
(Inscription)
Function
①I/O connector I/O connector for power supply, data and signal (D-sub 15-pin)
See section 4.3 for pin No.
②
CCG sensor fixing
plate
Metal plate that fixes the sensor head to the SC1.
③C ring Ring that fixes the magnet. Do not remove it.
POWER
PROTECT
HV
SET-1
SET-2
ULVAC
G-TRAN SC1
3
2
1

5
4.2. Front Panel
POWER
PROTECT
HV
SET-1
SET-2
ULVAC
G-TRAN SC1
1
2
4
5
6
7
3
Fig. 4-2 Front panel
No. Component
(Inscription)
Function
①POWER lamp
(POWER)
Lights when power is supplied to the sensor unit.
②PROTECT lamp
(PROTECT)
(Not used)
③HV lamp
(HV)
Lights when HV ON signal input.
④SET-1 lamp
(SET-1)
Lights when setpoint 1 is actuated.
⑤SET-2 lamp
(SET-2)
Lights when setpoint 2 is actuated.
⑥SET-1 setting
trimmer (SET-1)
Sets the value of setpoint 1 by adjusting the trimmer.
⑦SET-2 setting
trimmer (SET-2)
Sets the value of setpoint 2 by adjusting the trimmer.

6
4.3. Input/Output Connector
Fig. 4-3 Input/output connector pin assignment
Terminal
No.
*
Box unit Direction of signal Connected to
1
Power supply +24 V
Power
2
NC
Remote host
display unit
3
Setpoint actuating signal 1
4
Discharge OK/NG
5
HV ON/OFF
6
NC
7
Setpoint 1 set value
8
Measurement value (nonlinear
output)
9
Power ground
Power
10
OUT-COM (setpoint)
Remote host
display unit
11
Setpoint actuating signal 2
12
NC
13
NC
14
Setpoint 2 set value
15
Analog GND
* Do not make wiring connection to “NC”. Malfunction or damage can result.

7
5. INSTALLATION
5.1. Preparations
(1) Unpack the unit and check quantities. (See section 3.2)
(2) Check components to see if any components are damaged.
5.2. Installation
5.2.1. Installing the sensor head to the sensor unit
See section 10.
5.2.2. Installing the sensor unit
Install the sensor head to the
gauge port of the vacuum system.
(1) Measuring position
This gauge measures the
static pressure in the position
where the sensor head is installed. If there is a gas flow, source of outgas or intense
electrons or ions in the vacuum system, carefully select the measuring position so that
measurement is least affected by them.
(2) Installing the sensor head
• Install the sensor head in such a manner that the plane of the sensor mounting
port is parallel to gas flow. Ensure that gas does not enter the sensor head in the
form of beam. (See Fig. 5-1.)
• O-rings to be used in installing the sensor head should be as free from outgas as
possible. Use of rubber pipes or grease that release much outgas can be a cause
of error.
Fig. 5-1 Installing SC1
Vertical direction
O-ring gland
O-ring
Cap
Gauge port
Gas flow direction
POWER
PROTECT
HV
SET-1
SET-2
G-TRAN SC1
!
WARNING
Turn OFF power.
!
CAUTION
Beware of magnetic field.
!
CAUTION
Provide ventilation.
!
CAUTION
Keep out foreign matter.
!
CAUTION
Pay attention to operating
environment.
!
CAUTION
Check connection.

8
5.2.3. Electrical connection
Make electrical connection referring to the pin arrangement on section 4.3.
!
WARNING
Check line voltage.
!
CAUTION
Pay attention to operating conditions.
Cautions:
• Install the sensor head first and make electrical connection finally.
• GND [10pin] and GND [15pin] are common. Use these for the setpoint actuating
signal GND, setpoint set value GND and burnout detection GND.
• Power GND [9pin] and GND [10pin] [15pin] are common inside after being filtered
through the filter. Use power +24V [1pin] and power GND [9pin] in power line connection. If
other GND is used, measurement may be affected by noise. (See
Fig. 5-2.)
• Fix the cable so that undue force is not exerted to the connections of the cable.
• Securely tighten the connector fixing screws.
• In supplying power to the sensor unit, do not mistake pin numbers.
Fig. 5-2 Equivalent circuit in the power supply
FUSE
1
9
10
15 GND
FG
FG
+
24V
-
Filter Circuit
Measurement・
Control Circuit
Varistor
Filter
I/O
D-Sub 15P

9
6. CAUTIONS IN HANDLING
Beware of magnetic field
The magnetic flux density at the center of the sensor head is about
0.1 T. It will be attracted by or attract a metal part nearby with high
magnetic force. Be careful in maintenance that a screwdriver or a metal
part will be attracted with high magnetic force.
Use in a corrosive gas atmosphere
If this unit is exposed to chemically active gases including corrosive
gases and halogen or halogenated gases, problems will occur such as
pressure characteristics changing. When using this unit in these types
of environments, install an isolation valve between this unit and the
vacuum chamber and protect this unit as much as possible so it is not
exposed to these gases.
Use in a CVD gas atmosphere
If this unit is exposed to gases that deposit materials including CVD
(Chemical Vapor Deposition) material gases and rotary pump oil mist,
problems will occur such as pressure characteristics changing. When
using this unit in these types of environments, install an isolation valve
between this unit and the vacuum chamber and protect this unit so it
is not exposed to these gases.
Moisture and fouling
If there is a large quantity of f
ouling in the gauge head from the
gradual vaporization of moisture or organic matter, pressure accuracy
and response speed will be affected. Review installation locations and
methods so that fouling does not occur.
Gas type dependency
The pressure value and accuracy for this unit differ by the type of gas
measured. The accuracy for this unit is based on measuring nitrogen
gas. Be careful when using gases other than nitrogen.
• Start measurement more than one minute after turning on power and the output is
stabilized.
• Do not turn off the power to the sensor head during a sequence of measurements.
• The characteristics of the sensor head may change if it is exposed to a chemically active
or highly adsorptive gas. In that event, fill the sensor head with nitrogen or inert gas
or dry air with the sensor head energized with power and pump it for purging and
repeat this step. It may be restored to the original condition. However, do not spray
such gas to the opening of the sensor head for purging. If there is no prospect of the
characteristic being restored, replace the sensor head with a new one.
• The magnetron type vacuum gauge is sensitive to all types of gas, but the sensitivity
varies with the type of gas. The unit displays pressure by assuming that the gas is air.
• This gauge uses no consumable part like hot filament, but if a high voltage is applied
for an extended time at a pressure exceeding the higher limit of measurable pressure,
the sensor head interior may be contaminated.
• Be careful about pressure when starting measurement (start discharge by turning on
HV).It is difficult to discharge in the 10-5Pa(10-7Torr) range. In case it was impossible
to discharge , keep pressure more than 10-3Pa(10-5Torr) range and turn on HV.
• When pressure is more than measurable range, turn off HV and stop measurement.

10
7. OUTPUT SIGNALS
7.1. Control Operation
Contact leak current
Be aware of contact leak current. If a current of 0.1 mA or higher
flows between the input signal pin and the GND terminal, that may be
treated as signal input.
7.1.1. High Voltage ON/OFF [HV ON/OFF]
Turns ON/OFF the sensor head high voltage. (Lo input when HV is ON.)
Fig. 7-1 Signal input internal circuit diagram
7.2. Output Signals
Signals are outputted from the connector at the top of the sensor unit in the open
collector format. Fig. 7-2 shows its internal circuit.
7.2.1. Setpoint actuating signal [SET-1 ON/OFF][SET-2 ON/OFF]
The internal transistor will be actuated if the measured value is lower than the set
pressure. (Lo output when setpoint is ON.)
See section 4.3 for the pin numbers.
(→See section 8)
7.2.2. Discharge valid signal [Discharge OK/NG]
If the discharge current is flowing normally when the high voltage is turned ON,
Discharge Valid will be OK and the internal transistor will operate (Lo output when
Emission Valid is OK).
The Display unit (IM1R1/IM2R1) works while watching this signal. When the cable
production, a constipated line is necessary.
See section 4.3 for the pin numbers.
Output rating [24 VMAX, 50 mAMAX, saturation voltage is 1V]
Fig. 7-2 Signal output internal circuit diagram
（ON/OFF）2.4kΩ
5:HV
ON/OFF
10:Out-Com
15：A-GND
24V
LED
(ON/OFF)
3 :SetPoint1 ON/OFF
11：SetPoint2 ON/OFF
4 ：Discharge OK/NG
10:Out-Com
15：A-GND