Pfeiffer Vacuum IMR 265 User manual

BG 5172 BEN / B
(
2017-02
)
OPERATING INSTRUCTIONS
Translation of the original instructions
IMR 265
Compact Process Ion Gauge

2BG 5172 BEN / B (2017-02) IMR 265
In all communications with Pfeiffer Vacuum, please specify the information on the
product nameplate. For convenient reference copy that information into the space
provided below.
Pfeiffer Vacuum, D-35614 Asslar
Typ:
No:
F-No:
V W
This document applies to products with part number
PT R26 500 (flange DN 25 ISO-KF)
PT R26 501 (flange DN 40 ISO-KF)
PT R26 502 (flange DN 16 CF-F)
PT R26 503 (flange DN 40 CF-F)
PT R26 504 (flange DN 16 ISO-KF)
PT R26 505 (with 3/4" tube)
The part number (No) can be taken from the product nameplate.
We reserve the right to make technical changes without prior notice.
The IMR 265 Compact Process Ion Gauge has been designed for vacuum
measurement of non-flammable gases and gas mixtures in a pressure range
2×10-6 … 1000 hPa, measurement in the range of ≈1 … 1000 hPa serving as trend
indication (control range).
It must not be used for measuring flammable or combustible gases in mixtures
containing oxidants (e.g. atmospheric oxygen) within the explosion range.
The gauge is a part of the Pfeiffer Vacuum Compact Gauge family and can be
operated in connection with a Pfeiffer Vacuum measurement and control unit for
Compact Gauges or with another control device.
Over the whole measuring range, the measuring signal is output as logarithm of the
pressure.
The IMR 265 functions with a HP high pressure hot cathode ionization manometer,
which is controlled by the built-in Pirani manometer (control range). The hot cath-
ode is switched on only below the switching threshold of 5×10–2 hPa (to prevent
filament burn-out). For pressures above this threshold, the Pirani signal is output.
Product Identification
Validity
Intended Use
Functional Principle

BG 5172 BEN / B (2017-02) IMR 265 3
Contents
Product Identification 2
Validity 2
Intended Use 2
Functional Principle 2
1Safety 4
1.1 Symbols Used 4
1.2 Personnel Qualifications 4
1.3 General Safety Instructions 4
1.4 Liability and Warranty 4
2Technical Data 5
3Installation 9
3.1 Vacuum Connection 9
3.1.1 Removing and Installing the Electronics Unit 11
3.2 Power Connection 12
3.2.1 Use With a Measurement and Control Unit for Compact Gauges 12
3.2.2 Use With Other Control Devices 12
4Operation 14
4.1 Measuring Principle, Measuring Behavior 14
4.2 Operational Principle of the Gauge 17
5Maintenance 18
5.1 Maintenance 18
5.2 Adjusting the Gauge 18
5.3 Adjusting the Calibration Setting of the Hot Cathode System 19
5.4 Cleaning the Gauge 19
5.5 Replacing the Baffle 20
5.6 Replacing the Sensor 21
5.7 What to Do in Case of Problems 21
6Deinstallation 22
7Returning the Product 23
8Options 23
9Spare Parts 24
10 Disposal 24
Appendix 25
A: Conversion Table for Pressure Units 25
B: Relationship Output Signal – Pressure 25
C: Gas Type Dependence 26
For cross-references within this document, the symbol (→XY) is used, for cross-
references to other documents, the symbol (→[Z]).

4BG 5172 BEN / B (2017-02) IMR 265
1 Safety
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.
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 (→6) and the process
media.
Consider possible reactions (e.g. explosion) of the process media 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 con-
taminated. Adhere to the relevant regulations and take the necessary precau-
tions when handling contaminated parts.
Communicate the safety instructions to all other users.
Pfeiffer Vacuum assumes no liability and the warranty becomes null and void if the
end-user or third parties
•disregard the information in this document
•use the product in a non-conforming manner
•make any kind of changes (modifications, alterations etc.) to 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.
Gauge failures due to contamination or wear and tear, as well as expendable parts
(filament), are not covered by the warranty.
1.1 Symbols Used
1.2 Personnel Qualifications
1.3 General Safety
Instructions
1.4 Liability and Warranty

BG 5172 BEN / B (2017-02) IMR 265 5
2 Technical Data
Measuring range (air, N2)
Hot cathode
Pirani (control range)
2×10-6 … 1 hPa
1×10-2 … 1000 hPa
Repeatability
10-5 … 10-1 hPa
10-1 … 100 hPa
(after 10 min. stabilization)
≈2% measurement
≈30% measurement
Gas type dependence →Appendix C
Switching threshold
(selectable from 5 defined setpoints) 1 hPa
5×10–1 hPa
2×10–1 hPa
1×10–1 hPa
5×10–2 hPa (default)
Emission current
continually rising
From 1 hPa
To 2×10–6 hPa
4 µA
130 µA
Anode voltage 180 V
Voltage rating 0 … 10.2 V
Measuring range
Hot cathode
Pirani
1.5 … 7.5 V
8.5 … 9.75 V
Overrange hot cathode
Underrange hot cathode
Overrange Pirani
Underrange Pirani
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
Relationship voltage-pressure
Hot cathode
Pirani
→Appendix B
logarithmic
1.00 V / decade
0.25 V / decade
Error signals
0.3 V
0.5 V
→21
•hot cathode error
•Pirani error
•electronics unit not correctly
mounted to sensor
Minimum load 10 kΩ, short circuit proof
Resistor (Pin 1, Umax = 4.25 V) 15.2 kΩreferenced to supply common
Pirani
HV
ATM (<ATM> button)
automatic by hot cathode circuit in range
1 …3×10–3 hPa
via <ATM> button (keep button de-
pressed for at least 5 seconds) at at-
mospheric pressure
Hot cathode calibration setting with 16 position switch
according to label
Measurement
Emission
Output signal
Identification of the gauge
Adjustment
Supply

6BG 5172 BEN / B (2017-02) IMR 265
DANGER
The gauge may only be connected to power supplies, instruments or
control devices that conform to the requirements of a grounded pro-
tective extra-low voltage (PELV). The connection to the gauge has to
be fused 1).
Voltage at gauge 20 … 30 VDC 2)
max. ripple 1 V
pp
Power consumption
Standard
Emissions start (<200 ms)
≤0.5 A
≤1.4 A
Power consumption ≤16 W
Fuse necessary 1) ≤1.25 AT
Voltage at the power supply for
maximum cable length
21 … 30 V
max. ripple 1 V
pp
Electrical connection Hirschmann compact connector
type GO 6, 6 poles, male
Tightening torque ≤0.2 Nm
Cable 5 poles plus screening
Cable length max. 35 m (0.25 mm² conductor)
50 m (0.34 mm² conductor)
100 m (1.0 mm² conductor)
Vacuum flange-supply common direct electrical connection
Signal common-supply common conducted separately; only differential
measurement possible due to high
power consumption
Materials on the vacuum side
Housing, anode holder, screens
Feedthrough
Isolator
Cathode
Cathode holder
Pirani element
stainless steel
NiFe nickel plated
glass
iridium, yttrium oxide
molybdenum, platinum
tungsten, copper, glass
Internal volume
DN 25 ISO-KF
DN 40 ISO-KF
DN 40 CF-R
≤24 cm3
≤24 cm3
≤34 cm3
Pressure max. 500 kPa (absolute), (only for inert gases
and temperatures <100 °C)
1) Pfeiffer vacuum measurement and control units for Compact Gauges fulfill these requirements.
2) The minimum voltage of the power supply must be increased proportionally to the length of the sensor
cable.
Sensor cable
Grounding concept
Vacuum

BG 5172 BEN / B (2017-02) IMR 265 7
Admissible temperatures
Storage
Operation
Bakeout
-20 … 70 °C
0 … 50 °C
+ 50 °C (with electronics unit)
+ 80 °C (at the flange, with electronics
unit)
+150 °C (without electronics unit)
Relative humidity
Year's mean
During 60 days
≤65% (no condensation)
≤85% (no condensation)
Use indoors only
altitude up to 2000 m NN
Degree of protection IP 30
DN 16 ISO-KF flange and 3/4" tube
DN 16 KF
Rohr 3/4"
Weight ≈285 g
Environment
Dimensions [mm]

8BG 5172 BEN / B (2017-02) IMR 265
DN 25 ISO-KF and DN 40 ISO-KF flange
DN 25 KF
DN 40 KF
Weight ≈315 g
DN 16 CF-F and DN 40 CF-F flange
DN 16 CF-F
DN 40 CF-F
Weight ≈300 … 550 g

BG 5172 BEN / B (2017-02) IMR 265 9
3 Installation
DANGER
DANGER: overpressure in the vacuum system >100 kPa
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 clamps which are suited to overpressure.
DANGER
DANGER: hazardous voltages
Incorrectly grounded products can be extremely hazardous in the
event of a fault.
The gauge must be galvanically connected to the grounded vacuum
chamber. This connection must conform to the requirements of a
protective connection according to EN 61010:
•CF flanges fulfill this requirement.
•For gauges with a KF flange, use a conductive metallic clamping
ring.
•For the 3/4" tube, take appropriate measures to fulfill this require-
ment.
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 should be mounted so that no vibrations occur.
•The gauge may be mounted in any direction. However, no particles and con-
densates should penetrate into the measuring chamber.
•See dimensional drawings (→7) for space requirements.
•If the flange connection can only be made without the electronics unit, remove
the electronics unit (→11).
•The sensor can be baked out at up to 150 °C. For temperatures above 50 °C
the electronics unit must be removed (→11).
3.1 Vacuum Connection

10 BG 5172 BEN / B (2017-02) IMR 265
Remove the protective cap.
Notice:
Store the protective
cap and reinstall it
when deinstalling
the gauge.
Establish the flange connection.
Install the gauge in such a way that there is sufficient clearance for adjust-
ment (→16, 18, 19).
Procedure

BG 5172 BEN / B (2017-02) IMR 265 11
•Allen wrench AF 2.5
a) Carefully unfasten the hexagon socket set screw (1) on the side of the elec-
tronics unit (2). Make sure not to lose the hexagon socket set screw.
2
1
b) Remove the electronics unit without twisting it.
a) Place the electronics unit on the sensor (3) (be careful to correctly position the
pins and the guide notch (4)).
4
3
b) Slide the electronics unit up to the mechanical stop and lock it with the hexagon
socket set screw (1).
3.1.1 Removing and Installing
the Electronics Unit
Tools / material required
Removal
Mounting

12 BG 5172 BEN / B (2017-02) IMR 265
If the gauge is used with a
Pfeiffer Vacuum measurement
and control unit for Compact
Gauges, a corresponding sensor
cable is required (→23).
•Plug in the connector on the
gauge and secure it with the
screw (tightening torque
≤0.2 Nm).
•Connect the other end of the
cable to the measurement
and control unit and secure
it.
The gauge can also be used with other control devices. In such a case, an indi-
vidual sensor cable can be made (connector →23).
Due to the high power consumption, only differential measurement between the
signal output (pin 2) and the signal common (pin 3) is possible.


Open the connector
(ordering number
→23).
Prepare the cable.
Solder the sensor cable according to the diagram.
Power connection
Pin 1 identification (U ≤4.25 V)
Pin 2 signal output (measuring signal)
Pin 3 signal common GND
Pin 4 supply
Pin 5 supply common GND
Pin 6 screening
2
5
31
6
4
–
+
–
+
Degas
Degas
15.2 k
2
3
4
1
5
6
Connector,
soldering side
3.2 Power Connection
3.2.1 Use With a Measurement
and Control Unit for
Compact Gauges
3.2.2 Use With Other Control
Devices
Procedure

BG 5172 BEN / B (2017-02) IMR 265 13
WARNING
The supply common (pin 5) and the screen (pin 6) must be
connected at the power supply with protective ground.
Incorrect connection, incorrect polarity or inadmissible supply
voltages can damage the gauge.
Reassemble the connector.
Equip the other end of the cable with a connector which matches the
control device.
Plug in the connector.
Secure the connector on the gauge
with the screw (tightening torque
≤0.2 Nm).
Connect the other end of the cable to the control device.

14 BG 5172 BEN / B (2017-02) IMR 265
4 Operation
When the supply voltage is fed, the measuring signal is available between pins 2
and 3. Over the whole measuring range, the measuring signal is output as loga-
rithm of the pressure (relationship between output signal and pressure
→Appendix B).
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 IMR 265 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 Figure 1, which grants sensitivity, linearity, and stability even at high
pressures.
The measuring principle of this system is based on gas ionization. Electrons emit-
ted by the hot cathode (F) ionize a number of molecules proportional to the pres-
sure in the measuring chamber. The ion collector (IC) collects the thus generated
ion current I+and feeds it to the electrometer amplifier of the measuring instrument.
The ion current is dependent on the emission current Ie, the gas type, and the gas
pressure p according to the following relationship:
I+= Ie× p × C
Factor C represents the sensitivity of the gauge. It is generally specified for N2.
The lower measurement limit is 2×10-6 hPa.
In order for the entire range of 2×10-6 hPa … 1 hPa to be covered, the emission
current is continually increased from 4 µA at 1 hPa to 130 µA at 2×10-6 hPa (no
transients due to switching of the emission current).
Figure 1
Diagram of the HP measuring system
F hot cathode (filament)
IC ion collector
EC electron collector (anode grid)
ECIC
F
EC
IC
F
4.1 Measuring Principle,
Measuring Behavior
High pressure (HP) hot cathode

BG 5172 BEN / B (2017-02) IMR 265 15
Within certain limits, the thermal conductance of gases is pressure dependent. This
physical phenomenon is used for pressure measurement in the thermal con-
ductance 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 in Figure 2.
UB
IMR 265
+–
Figure 2
The bridge voltage UBis a measure for the gas pressure and is further processed
electronically (linearization, digitizing).
The IMR 265 covers the measuring range 2×10-6 ... 1000 hPa.
1000 hPa2 × 10-6 hPa
Hot cathode HP Pirani
5 × 10-2 hPa ... 1 hPa user-
definable threshold (setpoint)
•The Pirani permanently monitors the pressure.
•The hot cathode (controlled by the Pirani) is activated only at pressures
<1 ... 5×10-2 hPa (threshold can be set with a switch).
If the measured pressure is higher than the setpoint (which can be selected with a
switch within the range of 1 ... 5×10-2 hPa), the hot cathode remains off and the
Pirani value is output as signal (→Appendix B).
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.
Pirani (control range)
Measuring range
Switching threshold

16 BG 5172 BEN / B (2017-02) IMR 265
The IMR 265 has five definable switching thresholds. It is thus possible to prevent
the switching range from being situated within the process pressure range. The
factory setting of the threshold is 5×10–2 hPa. Another setpoint 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.
Caution
Since the switch position is only polled upon activation of the gauge,
the setpoint should be selected before the gauge is turned on.
Switch position Corresponding setpoint
0; 1
2; 3
4; 5
6; 7
8; 9
1 hPa
5×10–1 hPa
2×10–1 hPa
1×10–1 hPa
5×10–2 hPa (default)
The gauge is factory-calibrated. Adjustment may become necessary due to use in
different climatic conditions, extreme temperatures, contamination or aging
(→18).
The accuracy is reduced in the pressure range above 1×10-1 hPa and below
1×10-5 hPa.
The output signal is gas type dependent. The characteristic curves (→Appendix B)
are accurate for dry air, N2and O2. They can be mathematically converted for other
gases (→Appendix C).
If you are using a Pfeiffer Vacuum measurement and control unit for Compact
Gauges, you can enter a calibration factor to correct the displayed measured value
(→of the corresponding measurement unit).
Selecting the setpoint
Accuracy
Gas type dependence

BG 5172 BEN / B (2017-02) IMR 265 17
Gauge failures due to contamination or wear and tear, as well as ex-
pendable parts (filament), are not covered by the warranty.
The IMR 265 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 IMR 265 is factory-adjusted in such a way that the hot cathode is switched on
at ≈5×10–2 hPa. 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
(→21).
The measuring currents of the HP hot cathode/Pirani sensors are converted into a
pressure dependent frequency by a current/frequency-converter. A microcontroller
converts this frequency signal into a digital value of the measured pressure. This
value is output as analog measuring signal of 0 … 10.2 V at (pin 2 / pin 3), the valid
pressure range being 1.5 … 7.5 V (HP hot cathode) and 8.5 … 9.75 V (Pirani).
In addition to converting the measuring signal, the microcontroller's functions in-
clude monitoring of the emission and calculation of the total pressure based on the
measurements of the two sensors.
Contamination
4.2 Operational Principle of
the Gauge

18 BG 5172 BEN / B (2017-02) IMR 265
5 Maintenance
DANGER
DANGER: contaminated parts
Contaminated parts can be detrimental to health and environment.
Before beginning to work, find out whether any parts are contamina-
ted. Adhere to the relevant regulations and take the necessary pre-
cautions when handling contaminated parts.
The gauge is factory-calibrated. Through use in different climatic conditions, in-
stallation position, aging, contamination, exchange of the sensor (→21) a shift-
ing of the characteristic curve can occur and readjustment may thus become nec-
essary.
Adjustment is necessary when
•at atmospheric pressure, the output signal is <9.75 V (pressure indication
<1000 hPa)
•during venting, the output voltage of 9.75 V 1) (pressure indication 1000 hPa) is
reached before the pressure reading corresponds to atmosphere
1) The output voltage is limited to 10.2 V by the software.
The following steps have to be performed:
•HV adjustment Pirani
•ATM adjustment Pirani
When the gauge is activated, the Pirani measuring circuit is automatically adjusted
by the hot cathode circuit (when the pressure reaches the range
p = 1 … 3×10-3 hPa for the first time).
•Pin approx. ø1.3 × 50 mm (e.g. a bent open paper clip)
Operate the gauge at atmospheric pressure for approx. 10 minutes. If the
gauge was operated before in the hot cathode range, a cooling-down time
of approx. 30 minutes is to be expected (gauge temperature = ambient
temperature)..
Insert the pin through the opening marked <ATM> and push the button
inside for at least 5 s.
5.1 Maintenance
5.2 Adjusting the Gauge
HV adjustment Pirani
ATM adjustment Pirani
Required tools
Procedure

BG 5172 BEN / B (2017-02) IMR 265 19
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 setting and adjust it if necessary.
The sensor (except for the baffle) cannot be cleaned. In case of severe contami-
nation, it has to be replaced (→21). It can be assumed that the sensor is se-
verely contaminated if the measured values are no longer stable. Symptoms of
contamination are visible dirt and change of color.
A slightly damp cloth normally suffices for cleaning the outside of the gauge. Do not
use any aggressive or scouring cleaning agents.
Caution
Make sure that no liquids get inside the product. Allow the gauge to
dry thoroughly before putting it into operation again.
5.3 Adjusting the Calibra-
tion Setting of the Hot
Cathode System
5.4 Cleaning the Gauge

20 BG 5172 BEN / B (2017-02) IMR 265
The baffle can be replaced in case of severe contamination .
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.
•New baffle (→23)
•Screw driver No. 1
•Stick (e.g. pencil)
a) Carefully remove the baffle with the screw driver.
b) Carefully place the new baffle on the sensor opening.
c) Using a stick, carefully press the baffle down in the middle until it catches.
5.5 Replacing the Baffle
Tools / materials required
Procedure