Page 1
vacuum technologies
INSTRUCTION MANUAL
FRG-700
Inverted Magnetron
Pirani Gauge
Manual No. tqna48e1
Revision --
November 2008
Page 2
FRG-700 Inverted Magnetron Pirani Gauge
Copyright 2008
Vacuum Technologies
2
Page 3
FRG-700 Inverted Magnetron Pirani Gauge
Warranty
Products manufactured by Seller are warranted against defects in materials and workmanship for twelve (12) months from date of
shipment thereof to Customer, and Seller’s liability under valid warranty claims is limited, at the option of Seller, to repair, to replace, or refund of an equitable portion of the purchase price of the Product. Items expendable in normal use are not covered by
this warranty. All warranty replacement or repair of parts shall be limited to equipment malfunctions which, in the sole opinion of
Seller, are due or traceable to defects in original materials or workmanship. All obligations of Seller under this warranty shall
cease in the event of abuse, accident, alteration, misuse, or neglect of the equipment. In-warranty repaired or replaced parts are
warranted only for the remaining unexpired portion of the original warranty period applicable to the repaired or replaced parts.
After expiration of the applicable warranty period, Customer shall be charged at the then current prices for parts, labor, and transportation.
Reasonable care must be used to avoid hazards. Seller expressly disclaims responsibility for loss or damage caused by use of its
Products other than in accordance with proper operating procedures.
Except as stated herein, Seller makes no warranty, express or implied (either in fact or by operation of law), statutory or otherwise; and, except as stated herein, Seller shall have no liability under any warranty, express or implied (either in fact or by operation of law), statutory or otherwise. Statements made by any person, including representatives of Seller, which are inconsistent or
in conflict with the terms of this warranty shall not be bin-ding upon Seller unless reduced to writing and approved by an officer of
Seller.
Warranty Replacement and Adjustment
All claims under warranty must be made promptly after occurrence of circumstances giving rise thereto, and must be received
within the applicable warranty period by Seller or its authorized representative. Such claims should include the Product serial
number, the date of shipment, and a full description of the circumstances giving rise to the claim. Before any Products are returned for repair and/or adjustment, written authorization from Seller or its authorized representative for the return and instructions
as to how and where these Products should be returned must be obtained. Any Product returned to Seller for examination shall
be prepaid via the means of transportation indicated as acceptable by Seller. Seller reserves the right to reject any warranty claim
not promptly reported and any warranty claim on any item that has been altered or has been returned by non-acceptable means
of transportation. When any Product is returned for examination and inspection, or for any other reason, Customer shall be responsible for all damage resulting from improper packing or handling, and for loss in transit, not withstanding any defect or nonconformity in the Product. In all cases, Seller has the sole responsibility for determining the cause and nature of failure, and
Seller’s determination with regard thereto shall be final.
If it is found that Seller’s Product has been returned without cause and is still serviceable, Customer will be notified and the Product returned at Customer’s expense; in addition, a charge for testing and examination may be made on Products so returned.
3/1/00
3
Page 4
Product Identification
FRG-700 Inverted Magnetron Pirani Gauge
In all communications with VARIAN, please specify the information given on the
product nameplate. For convenient reference copy that information into the space
provided below:
VARIAN Lexington MA 02421 USA
Model:
PN:
SN:
V W
Validity
Intended Use
Functional Principle
This document applies to products with part numbers:
FRG700KF25
(DN 25 ISO-KF)
FRG700CF35 (DN 40 CF-F)
The part number (PN) can be taken from the product nameplate.
If not indicated otherwise in the legends, the illustrations in this document correspond to the gauge with vacuum connection DN 25 ISO-KF. They apply to the
gauge with other vacuum connection by analogy.
We reserve the right to make technical changes without prior notice.
All dimensions in mm.
The Inverted Magnetron Pirani Gauge FRG-700 has been designed for vacuum
measurement in the pressure range of 5×10
-9
… 1000 mbar.
The Inverted Magnetron Pirani Gauge must not be used for measuring flammable
or combustible gases which react in air.
The gauge can be operated in connection with a VARIAN FRG Control Unit, a
VARIAN Turbo AG Rack Controller, or with another controller.
Over the whole measuring range, the measuring signal is output as a logarithm of
the pressure.
The gauge consists of two separate measurement systems (Pirani and cold
cathode system) the signals of which are combined in such a way that one
measurement signal is output. The Pirani measurement circuit is always on.
4
Page 5
Contents
FRG-700 Inverted Magnetron Pirani Gauge
Warranty 3
Warranty Replacement and Adjustment 3
Product Identification 4
Validity 4
Intended Use 4
Functional Principle 4
Safety 6
1
1.1 Symbols Used 6
1.2 Personnel Qualifications 6
1.3 General Safety Instructions 6
2 Technical Data 7
3 Installation 10
3.1 Vacuum Connection 10
3.1.1 Removing the Magnet Unit (Only for Gauges With CF Flanges) 12
3.2 Electrical Connection 13
3.2.1 Use With an VARIAN Controller 13
3.2.2 Use With Another Control Device 13
4 Operation 14
4.1 Measurement Principle, Measuring Behavior 14
5 Deinstallation 16
6 Maintenance 17
6.1 Adjusting the Gauge 17
6.2 Cleaning and Replacing Parts 19
6.2.1 Disassembling 19
6.2.2 Cleaning 20
6.2.3 Reassembling 21
6.3 Troubleshooting 23
7 Spare Parts 24
8 Returning the Product 25
9 Disposal 25
Appendix 26
A: Measuring Signal vs. Pressure 26
B: Gas Type Dependence 27
For cross-references within this document, the symbol (→ XY) is used.
5
Page 6
1 Safety
1.1 Symbols Used
FRG-700 Inverted Magnetron Pirani Gauge
DANGER
Information on preventing any kind of physical injury.
WARNING
Information on preventing extensive equipment and environmental damage.
1.2 Personnel Qualifications
1.3 General Safety
Instructions
Caution
Information on correct handling or use. Disregard can lead to malfunctions or
minor equipment damage.
Notice
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.
• Adhere to the applicable regulations and take the necessary precautions for the
process media used.
Consider possible reactions between the materials (→ 7) and the process
media.
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 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.
DANGER
DANGER: magnetic fields
Strong magnetic fields can disturb electronic devices like heart
pacemakers or impair their function.
Maintain a safety distance of ≥10 cm between the magnet and the
heart pacemaker or prevent the influence of strong magnetic fields by
Communicate the safety instructions to all other users.
6
antimagnetic shielding.
Page 7
2 Technical Data
FRG-700 Inverted Magnetron Pirani Gauge
Measuring range (air, N2) 5×10-9 … 1000 mbar
Accuracy (N2)
Reproducibility
Gas type dependence
≈±30%
in the range 1×10
≈±5%
in the range 1×10
→ Appendix B
-8
… 100 mbar
-8
… 100 mbar
Output signal (measuring signal)
Voltage range 0 … +10.5 V
Measuring range 1.82 … 8.6 V
Voltage vs. pressure logarithmic, 0.6 V / decade
(→ Appendix )
Error signal <0.5 V no supply
>9.5 V Pirani measurement element
defective (filament rupture)
Output impedance
Minimum loaded impedance
2×10 Ω
10 kΩ, short-circuit proof
Response time (pressure dependent)
-6
mbar
p > 10
p = 10
-8
mbar
<10 ms
≈1000 ms
Gauge identification
85 kΩ referenced to supply common
Status Pin 6
-2
mbar
p > 10
Pirani-only mode
-2
p < 10
mbar
Cold cathode not ignited
Low = 0 V
Low = 0 V
Pirani-only mode
-2
mbar
p < 10
Cold cathode ignited
High = 15 … 30 VDC
Combined Pirani / cold cathode
mode
Lamp High voltage on (LED on)
Supply
DANGER
The gauge may 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
Supply voltage at the gauge
Power consumption
Fuse1)
The minimum voltage of the power supply must be increased proportionally to the
length of the sensor cable.
Voltage at the supply unit with
maximum line length
1)
VARIAN controller fulfill these requirements.
7
1)
.
15.0 … 30.0 VDC (ripple ≤ 1 Vpp)
≤2 W
≤1 AT
16.0 … 30.0 VDC (ripple ≤ 1 V
)
pp
Page 8
FRG-700 Inverted Magnetron Pirani Gauge
Adjustment
-4
<HV> potentiometer at <10
mbar
<ATM> potentiometer at atmospheric pressure
Electrical connection FCC68 female, 8 poles
Sensor cable 8 conductors plus shielding
Line length
≤50 m (8×0.14 mm²)
Operating voltage
Operating current
≤3.3 kV
≤500 µA
Grounding concept
Vacuum connection-signal common
→ ("Electrical Connection")
connected via 10 kΩ
(max. voltage differential
with respect to safety ±50 V
with respect to accuracy ±10 V)
Supply common-signal common conducted separately
Materials exposed to vacuum
Vacuum connection
Measuring chamber
Feedthrough
Internal seals
Anode
Ignition aid
Pirani measuring tube
Pirani filament
stainless steel
stainless steel
ceramic
FPM 75
Mo
stainless steel
Ni, Au
W
Mounting orientation any
Internal volume
Pressure
≈20 cm³
≤10 bar (absolute)
limited to inert gases
Temperatures
Operation +5 … +55 °C
Bakeout +150 °C
(without magnetic shielding and
electronics unit)
Pirani filament +120 °C
Storage –40 °C … +65 °C
Relative humidity
≤80% at temperatures up to +31 °C
decreasing to 50% at +40 °C
Use indoors only
altitude up to 2000 m
Protection category IP 40
8
Page 9
FRG-700 Inverted Magnetron Pirani Gauge
Dimensions [mm]
75
60
55
92
18
DN 25 ISO-KF
Weight
FRG700KF25
FRG700CF35
28
ø 63.5
24
DN 40 CF-F
≈700 g
≈980 g
9
Page 10
3 Installation
3.1 Vacuum Connection
FRG-700 Inverted Magnetron Pirani Gauge
DANGER
DANGER: 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
DANGER: overpressure in the vacuum system >2.5 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: protective ground
Products that are not professionally connected to ground can be
extremely hazardous in the event of a fault.
The gauge must be electrically connected to the grounded vacuum
chamber. The connection must conform to the requirements of
protective connection according to EN 61010:
• CF connections fulfill this requirement.
• For gauges with KF connections, use a conductive metallic clam-
ping ring.
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.
Caution: dirt sensitive area
Touching the product or parts thereof with bare hands increases the
desorption rate.
Always wear clean, lint-free gloves and use clean tools when working
in this area.
DANGER
Caution
Caution
10
WARNING: electric arcing
Helium may cause electric arcing with detrimental effects on the
electronics of the product.
Before performing any tightness tests put the product out of operation
and remove the electronics unit.
WARNING
Page 11
Procedure
FRG-700 Inverted Magnetron Pirani Gauge
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 and possibly use a seal with a
centering ring and filter.
If adjustment should be possible after the gauge has been installed, be
sure to install it so that the <HV> and <ATM> trimmer potentiometers
can be accessed with a screw driver (→ 17).
When making a CF flange connection, it may be advantageous to
temporarily remove the electronics and the magnet unit (→ 12).
Remove the protective lid and connect the product to the vacuum system.
Seal with centering ring
or
Protective lid
Clamp
Seal with centering
ring and filter
Keep the protective lid.
11
Page 12
3.1.1 Removing the Magnet
Unit (Only for Gauges
With CF Flanges)
Tools required
Procedure
FRG-700 Inverted Magnetron Pirani Gauge
• Allen wrench AF 1.5
• Open-end wrench AF 7
4
3
7
2
1
a) Unfasten the hexagon socket set screw (1) on the electronics unit (2).
b) Remove the electronics unit without twisting it.
c) Unfasten the hexagon head screw (3) on the magnet unit (4) and remove the
magnet unit.
The magnetic force and the tendency to tilt make it difficult to
separate the magnet unit and the measuring chamber (7).
d) Make the flange connection between the gauge and the vacuum system.
e) Remount the magnet unit and lock it with the hexagon head screw (3).
f) Carefully mount the electronics unit (2). (Make sure the pin of the Pirani ele-
ment is properly plugged into the corresponding hole of the electronics unit.)
g) Push the electronics unit up to the mechanical stop and lock it with the hexagon
socket set screw (1).
12
Page 13
3.2 Electrical Connection
Precondition
3.2.1 Use With an VARIAN
Controller
FRG-700 Inverted Magnetron Pirani Gauge
Make sure the vacuum connection is properly made (→ 10).
Connect the sensor cable to the gauge and the controller.
3.2.2 Use With Another Control
Device
n Make a sensor cable according to the diagram.
10
10
Ident
)
Electrical connection
Pin 1 Supply (
Pin 2 Supply common
Pin 3 Signal output
(measuring signal)
Pin 4 Identification
Pin 5 Signal common
Pin 6 Status
Pin 7, 8 n.c.
Signal
10 k
15 … 30 VDC
6
3
5
4
1
2
1
8
8 poles FCC-68
+
–
+
–
o Connect the sensor cable to the gauge and the controller.
13
Page 14
4 Operation
4.1 Measurement Principle,
Measuring Behavior
FRG-700 Inverted Magnetron Pirani Gauge
As soon as the required supply voltage is applied, the measuring signal is available
between pins 3 and 5. (
→ Appendix for the relationship between the measuring
signal and the pressure).
Allow for a stabilizing time of approx. 10 min. Once the gauge has been switched
on, permanently leave it on irrespective of the pressure.
The gauge consists of tow separate measuring systems (Pirani and cold cathode
system according to the inverted magnetron principle). They are combined in such
a way that for the user, they behave like one measuring system.
The optimum measuring configuration for the particular pressure range, in which
measurement is performed, is used:
10-4 mbar
1000 mbar
Cald cathode Pirani
-2
5×10-9 mbar
• The Pirani measuring circuit is always on
• The cold cathode measuring circuit is controlled by the Pirani circuit and is
activated only at pressures <1×10
-2
The identification output (pin 6) indicates the current status of the gauge:
Pressure Lamp on the
Operating mode Pin 6
gauge
10
mbar
mbar
Gas type dependence
Ignition delay
p > 1×10-2 mbar
Pirani-only mode Low = 0 V
p < 1×10-2 mbar
Cold cathode not
ignited
Low = 0 V
Pirani-only mode
p < 1×10-2 mbar
Cold cathode ignited
Combined Pirani / cold
High = 15 … 30 VDC
cathode mode
As long as the cold cathode measuring circuit has not ignited, the measuring value
of the Pirani is output as measuring signal (if p < 5
-4
×10
mbar, "Pirani underrange"
is displayed).
The measuring signal depends on the type of gas being measured. The curves are
accurate for dry air, O
other gases (
→ Appendix B).
, CO and N2. They can be mathematically converted for
2
If you are using an VARIAN controller, you can enter a calibration factor to correct
the pressure reading (
→ of that controller).
When cold cathode measuring systems are activated, an ignition delay occurs. The
delay time increases at low pressures and is typically:
-5
mbar ≈1 second
10
-7
mbar ≈20 seconds
10
-9
5×10
mbar ≈2 minutes
14
Page 15
Contamination
FRG-700 Inverted Magnetron Pirani Gauge
As long as the cold cathode measuring circuit has not yet ignited, the measured
value of the Pirani is output as measuring signal ("Pirani underrange" is displayed
for pressures <5
-4
×10
mbar). The identification output (pin 6, low) indicates the
Pirani-only mode.
If the gauge is activated at a pressure p < 3×10-9, the gauge cannot
recognize whether the cold cathode system has ignited. It indicates
"Pirani underrange".
Once flanged on, permanently leave the gauge in the operating mode
irrespective of the pressure range. Like this, the ignition delay of the cold
cathode measuring circuit is always negligible (<1 s), and thermal
stabilizing effects are minimized.
Gauge failures due to contamination, as well as expendable parts
(filament), are not covered by the warranty.
Gauge contamination is influenced by the process media used as well as by any
present or new contaminants and their respective partial pressures. Continuous
operation in the range of 10
as well as reduced up-time and maintenance cycles. With constantly low pressures
(p <1
-6
×10
mbar), the gauge can be operated for more than one year without
cleaning (cleaning the gauge
-4
mbar … 10-2 mbar can cause severe contamination
→ 19).
Contamination of the gauge generally causes a deviation of the measured values:
• In the high pressure range (1×10
-3
mbar … 0.1 mbar), the pressure reading is
too high (contamination of the Pirani element). Readjustment of the Pirani
measuring system
• In the low pressure range (p < 1×10
→ 17.
-3
mbar), the pressure reading is usually too
low (contamination of the cold cathode system). In case of severe contamination, instabilities can occur (layers of the measuring chamber peel off).
Contamination due to insulation layers can even lead to a complete failure of
the discharge ("Underrange" is displayed).
Contamination can to a certain extent be reduced by:
• geometric protection measures (e.g. screenings, elbows) for particles that
spread rectilinearly
• mounting the flange of the gauge at a place where the partial pressure of the
pollutants is particularly low.
Special precautions are required for vapors deposited under plasma (of the cold
cathode measuring system). It may even be necessary to temporarily switch of the
gauge while such vapors occur.
15
Page 16
5 Deinstallation
FRG-700 Inverted Magnetron Pirani Gauge
DANGER
DANGER: 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.
Procedure
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.
Caution
Caution: dirt sensitive area
Touching the product or parts thereof with bare hands increases the
desorption rate.
Always wear clean, lint-free gloves and use clean tools when working
in this area.
n Vent the vacuum system.
o Put the gauge out off operation and unplug the sensor cable.
p Remove the gauge from the vacuum system and install the protective lid.
16
When deinstalling the CF flange connection, it may be
advantageous to temporarily remove the magnet unit (
Protective lid
→ 12).
Page 17
6 Maintenance
FRG-700 Inverted Magnetron Pirani Gauge
Gauge failures due to contamination, as well as expendable parts
(filament), are not covered by the warranty.
DANGER
DANGER: 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.
6.1 Adjusting the Gauge
Tools required
Procedure
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.
Caution
Caution: dirt sensitive area
Touching the product or parts thereof with bare hands increases the
desorption rate.
Always wear clean, lint-free gloves and use clean tools when working
The gauge is factory-calibrated. If used under different climatic conditions, through
extreme temperatures, aging or contamination, and after exchanging the sensor,
the characteristic curve can be offset and readjustment may become necessary
The cold cathode measuring circuit, which is dominant for low pressures
(<1×10
the Pirani measuring circuit can be adjusted. Any adjustment has a negligible effect
on the pressure range between approx. 10
• Screw driver 1.5 mm
• Cylindrical pin ø≈3 mm
in this area.
-3
mbar), is factory-calibrated and cannot be adjusted. By way of contrast,
-2
mbar and 102 mbar.
n If you are using a seal with centering ring and filter, check that they are
clean or replace them if necessary (
→ 16).
o Put the gauge into operation (if possible, in the position, in which it will be
used later on).
p Evacuate the vacuum system to p << 10
-4
mbar, and then wait 10 minutes.
q Turn the nameplate counter-clockwise until the mechanical stop is reached.
17
Page 18
FRG-700 Inverted Magnetron Pirani Gauge
r
While depressing the pin with the cylindrical pin, adjust the <HV>
potentiometer …
… to 4.20 V or … to 5×10
-4
mbar.
After that, turn the potentiometer
counter-clockwise by 1/3 of a turn.
s Vent the gauge with air or nitrogen to atmospheric pressure, and wait at
least 10 minutes.
t Turn the nameplate clockwise until the mechanical stop is reached.
u
Using the 1.5 mm screwdriver, adjust the <ATM> potentiometer …
… to 8.60 V or … to 1×10
3
mbar.
18
v Turn the nameplate back to its original position (it catches).
Page 19
6.2 Cleaning and Replacing
Parts
Tools / material required
6.2.1 Disassembling
FRG-700 Inverted Magnetron Pirani Gauge
DANGER
DANGER: cleaning agents
Cleaning agents can be detrimental to health and environment.
Adhere to the relevant regulations and take the necessary precautions
when handling cleaning agents and disposing of them. Consider
• Allen wrench AF 1.5
• Allen wrench AF 3
• Open-end wrench 7.0 mm
• Pliers for circlip
• Polishing cloth (400 grain) or Scotch-Brite
• Tweezers
• Cleaning alcohol
• Mounting tool for ignition aid
• Ignition aid
• Pirani element (13) incl. FPM seal (13a)
• FPM seal (11) for anode feedthrough
possible reactions with the product materials (
We recommend replacing the Pirani element when cleaning the gauge.
→ 8).
2
1
4
3
7
10
8a
8
9
6
5
13a
13
12
10a
11
n Remove the gauge from the vacuum system (→ 16).
o Unfasten the hexagon socket set screw (1) on the electronics unit (2).
p Remove the electronics unit without twisting it.
The cover of the electronics unit cannot be removed.
19
Page 20
6.2.2 Cleaning
Cleaning the measuring
chamber and the polarity
insert
FRG-700 Inverted Magnetron Pirani Gauge
q Unfasten the hexagon head screw (3) on the magnet unit (4) and remove
the magnet unit.
The magnetic force and the tendency to tilt make it difficult to
separate the magnet unit and the measuring chamber (7).
r Remove the circlip (5) and the polarity insert (6) from the measuring
chamber
s Remove the three hexagon socket screws (8) incl. lock washers (8a) on the
back of the measuring chamber.
t Carefully remove the following parts in this order (without exerting stress on
the Pirani element (13)): pressure piece (9), complete anode (10), FPM seal
(11) incl. support ring (12), Pirani element (13) incl. FPM seal (13a).
The parts can now be cleaned or replaced individually.
n Using a polishing cloth rub the inside walls of the measuring chamber and
the polarity insert to a bright finish.
Cleaning or replacing the
anode
The sealing surfaces must only be worked concentrically.
o Rinse the measuring chamber and the polarity insert with cleaning alcohol.
p Allow both to dry.
n Remove the used ignition aid (10a) with tweezers.
o Using a polishing cloth rub the anode pin to a bright finish.
Do not bend the anode. Do not carry out mechanical work on the
ceramic part.
p Rinse the anode with cleaning alcohol.
q Allow the anode to dry.
r Insert a new ignition aid (10a) into the mounting tool.
s Carefully press the anode (clean or new)
centered and parallel to the tool axis into
the ignition aid and insert it to a depth of
approx. 15 mm. The final positioning is
established after the anode is installed.
Anode
Ignition aid
Mounting tool
20
Page 21
Cleaning the Pirani element
Replacing the Pirani element
FRG-700 Inverted Magnetron Pirani Gauge
n Remove the FPM seal (13a) from the Pirani element (13).
o Fill the Pirani measuring tube with cleaning alcohol and let it work.
p Pour the alcohol out of the tube.
q Dry the tube (e.g. with a blow dryer <150 °C).
r Slide a new FPM seal over the Pirani element and insert it into the corre-
sponding groove.
s Reinstall the Pirani element (→ 21).
If it is severely contaminated or defective.
n Slide a new FPM seal (13a) over the Pirani element (13) and insert it into
the corresponding groove.
6.2.3 Reassembling
o Mount the Pirani element (→ 21).
(→ figure 19)
n Insert the FPM seal (11) with the support ring (12) centered into the
measuring chamber (7). The sealing surface, seal, and ceramic part must
be clean.
o Carefully insert the anode (10) incl. ignition aid (10a) into the measuring
chamber.
p Insert the Pirani element (13) with the FPM seal (13a) slid over it into the
corresponding bore hole.
q Carefully place the pressure piece (9) on the measuring chamber and
tighten them with the three hexagon socket screws (8) incl. lock washers
(8a) uniformly until the stop position is reached.
r Position the ignition aid (10a) by pushing the mounting tool over the anode
pin until the mechanical stop is reached.
s Blow the particles in the measuring chamber with dry nitrogen (be careful to
hold the measuring chamber with the flange pointing downwards).
t Slide the polarity insert (6) into the measuring chamber until the mechanical
stop is reached.
u Place the circlip (5) snugly fitting on the polarity insert.
Visually check that the anode pin is centered over the middle
21
hole of the polarity insert (max. eccentricity = 0.5 mm).
Page 22
FRG-700 Inverted Magnetron Pirani Gauge
v If possible perform a leak test (leak rate <10
-9
mbar l/s).
WARNING
WARNING: electric arcing
Helium may cause electric arcing with detrimental effects on the
electronics of the product.
Before performing any tightness tests put the product out of
operation and remove the electronics unit.
w Mount the magnet unit (4) and lock it with the screw (3).
Carefully mount the electronics unit (2). (Make sure the pin of the Pirani ele-
ment is properly plugged into the corresponding hole of the electronics unit.)
Push the electronics unit up to the mechanical stop and lock it with the
hexagon socket set screw (1).
Adjust the gauge (→ 17).
22
Page 23
6.3 Troubleshooting
FRG-700 Inverted Magnetron Pirani Gauge
Problem Possible cause Remedy
Measuring signal
continually < 0.5 V
No supply voltage. Turn on the power
supply.
"Error low".
Measuring signal
continually > 9.5 V
"Error high".
Pirani measurement
element defective
(filament rupture).
Electronics unit not cor-
rectly mounted.
The green lamp is ON and
the identification indicates
The cold cathode dis-
charge has not ignited.
Pirani-only mode (measuring signal continually
> 4.0 V)
"Pirani underrange".
The FRG has only been
Measuring signal continually > 5 V or display
-3
> 10
mbar although
vacuum pressure is OK.
activated with
p < 3×10
Pirani measurement cir-
cuit not adjusted, e.g.
due to severe contami-
nation.
—9
mbar.
Replace the Pirani
element (
→ 21).
Mount the electronics
unit correctly (
→ 21).
Wait until the gas discharge ignites (in case of
contamination with insulation layers, the cold
cathode may completely
fail to ignite).
(Cleaning
→ 19).
Slightly increase the
pressure.
Readjust the Pirani
measurement circuit
(
→ 17). If adjustment
is impossible, replace the
Pirani element.
Measurement of heavy
gases.
Severe outgassing in the
cold cathode measuring
Convert with the corresponding formula
(
→ 27).
Clean the measuring
chamber.
chamber.
Measuring signal unstable. Gauge contaminated. Clean the gauge
(
→ 19).
23
Page 24
7 Spare Parts
13
13a
11
12
10a
10
FRG-700 Inverted Magnetron Pirani Gauge
When ordering spare parts, always mention:
• all information on the product nameplate
• description and ordering number according to the spare parts list
Pos. Description Ordering number
12
13a
11
10a
Maintenance kit, consisting of:
1× support ring
1× O-ring FPM ø3.69×1.78
1× O-ring FPM ø10.82× 1.78
3× ignition aid
13
12
13a
11
10a
10
Repair kit, consisting of:
1× Pirani element
1× support ring
1× O-ring FPM ø3.69×1.78
1× O-ring FPM ø10.82×1.78
3× ignition aid
1× anode, complete
FRG700MAINT
FRG700REPR
24
Page 25
8 Returning the Product
FRG-700 Inverted Magnetron Pirani Gauge
WARNING
WARNING: forwarding contaminated products
Contaminated products (e.g. radioactive, toxic, caustic or biological
hazard) can be detrimental to health and environment.
Products returned to VARIAN should preferably be free of harmful
substances. Adhere to the forwarding regulations of all involved countries and forwarding companies and enclose a duly completed decla-
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 of contamination are
returned to the sender at his own expense.
ration of contamination.
9 Disposal
Separating the components
Contaminated components
Other components
DANGER
DANGER: 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.
WARNING
N
After disassembling the product, separate its components according to the
following criteria:
Contaminated components (radioactive, toxic, caustic or biological hazard etc.)
must be decontaminated in accordance with the relevant national regulations,
separated according to their materials, and disposed of.
Such components must be separated according to their materials and recycled.
WARNING: substances detrimental to the environment
Products or parts thereof (mechanical and electric components, operating fluids etc.) can be detrimental to the environment.
Dispose of such substances in accordance with the relevant local regulations.
25
Page 26
Appendix
A: Measuring Signal vs.
Pressure
Conversion formulae
Conversion curves
FRG-700 Inverted Magnetron Pirani Gauge
p = 10
1.667U-d
⇔
U = c + 0.6log10 p
p U c d
[mbar]
[Torr]
[Pa]
[V]
[V]
[V]
6.8
6.875
5.6
11.33
11.46
9.333
where p pressure
U measuring signal
c, d constant (pressure
unit dependent
valid in the range 5×10
Pressure p
3.8×10
5×10
-9
mbar < p
-9
Torr < p
-7
Pa < p
<1000 mbar
<750 Torr
5
pa
<1×10
Conversion table
1E+04
1E+02
1E+00
1E–02
1E–04
1E–06
1E–08
underrange
sensor error
0.0
0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5
Measuring signal U [V
]
Pa
mbar
torr
overrange
9.5 10.5
sensor error
Meas. signal U [V] Pressure p [mbar] Pressure p [Torr] Pressure p [Pa]
<0.5 Sensor error
0.5 … 1.82 Underrange
1.82
2.0
2.6
3.2
3.8
4.4
5.0
5.6
6.2
6.8
7.4
8.0
8.6
5.0×10
1.0×10
1.0×10
1.0×10
1.0×10
1.0×10
1.0×10
1.0×10
0.1
1.0
10
100
1000
-9
-8
-7
-6
-5
-4
-3
-2
3.8×10
7.5×10
7.5×10
7.5×10
7.5×10
7.5×10
7.5×10
7.5×10
7.5×10
0.75
7.5
75
750
-9
-9
-8
-7
-6
-5
-4
-3
-4
5.0×10
1.0×10
1.0×10
1.0×10
1.0×10
1.0×10
0.1
1.0
10
-7
-6
-5
-4
-3
-2
100
1000
4
1.0×10
1.0×10
5
8.6 … 9.5 Overrange
9.5 … 10.5 Sensor error (Pirani defective)
26
Page 27
B: Gas Type Dependence
Indication range above
-2
10
mbar
Indication range
-6
10
… 0.1 mbar
FRG-700 Inverted Magnetron Pirani Gauge
Pressure indicated (gauge calibrated for air).
p (mbar)
2
10
8
6
4
2
1
10
8
6
4
2
0
10
8
6
4
2
–1
10
8
6
4
2
–2
10
10
Water vapor
–3
24
Indication range
above 10
–2
10
6
8
24
-2
mbar
–1
10
68
246824
Pressure indicated (gauge calibrated for air).
p (mbar)
–1
10
8
6
4
Indication range
-6
... 10
-1
mbar
10
Ar
Air
N
2
O
2
CO
He
–5
10
8 2 468 2 46 2 46 2 46
–4
10
10
10
10
10
10
2
–2
8
6
4
2
–3
8
6
4
2
–4
8
6
4
2
–5
8
6
4
2
–6
10
–6
246
H2He Ne
Air
N
2
O
2
CO
CO
2
Ar
Freon 12
Kr
Xe
0
10
–3
10
8
68
8
10
10
1
24
–2
p
eff
p
eff
10
68
(mbar)
10
8
(mbar)
2
–1
27
Page 28
Indication range below
-5
10
mbar
FRG-700 Inverted Magnetron Pirani Gauge
In the range below 10-5 mbar, the pressure indication is linear. For gases other
than air, the pressure can be determined by means of a simple conversion formula:
p
= K × pressure indicated
eff
where gas type K
air (O2, CO, N2) 1.0
Xe 0.4
Kr 0.5
Ar 0.8
H
2.4
2
Ne 4.1
He 5.9
These conversion factors are average values.
A mixture of gases and vapors is often involved. In this case,
accurate determination is only possible with a partial pressure
measurement instrument, e.g. a quadrupole mass spectrometer.
28
Page 29
Notes
FRG-700 Inverted Magnetron Pirani Gauge
29
Page 30
Varian Vacuum Technologies
121 Hartwell Avenue
Lexington, MA, 02421 USA
Tel: (781) 861 7200
Fax: (781) 861 5437
Original: English custserv@varianinc.com
t qna48e1
www.varianinc.com
Loading...