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FMA 3100/3100ST/3300/3300ST Series
Thermal Mass Flow Sensors and Meters
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M-4270/0707, pg. 2 of 29
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READ THIS MANUAL COMPLETELY BEFORE ATTEMPTING TO CONNECT OR
OPERATE YOUR FLOW SENSOR. FAILURE TO DO SO MAY RESULT IN INJURY
TO YOU OR DAMAGE TO THE FLOW SENSOR.
TABLE OF CONTENTS
A. Introduction .............................................................................................4
1. Unpacking...........................................................................................4
2. Product Overview And Principle Of Operation..........................................4
B. Installation...............................................................................................5
1. General Considerations.........................................................................5
2. Mounting The Flow Sensor Or Flow Meter ...............................................6
3. Tubing Connections..............................................................................7
a) General .......................................................................................7
b) High Flow Units (0-100 L/min and above)............................................7
5. Electrical Connections ...........................................................................7
a) Overview ....................................................................................7
b) Connecting the 6 Pin Mini Din Connector.............................................8
c) Connecting the 6 Pin Mini Din Connector And FMA 3000C Cable...........9
d) Connections for the 9 Pin D Sub Connector........................................10
e) Connections for the 15 Pin D Sub Connector ...................................... 11
f) Using the 0-5VDC Output Power Adapter Package ..............................12
C. Operation ............................................................................................. 13
1. Warm-Up .......................................................................................... 13
2. Verification Of Zero ............................................................................13
3. Flow Readings....................................................................................13
4. Zero Adjustments................................................................................14
5. Recalibration...................................................................................... 15
D. Maintenance And Product Care................................................................15
1. General............................................................................................. 15
2. Returning Units For Repair Or Recalibration............................................15
E. Specifications......................................................................................... 16
F. Dimensions............................................................................................17
G. Gas K Factors ........................................................................................25
H. Trouble Shooting Guide ..........................................................................26
M-4270/0707, pg. 3 of 29
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A. Introduction
1. Unpacking
All sensors are suitably packaged to prevent damage during shipping. If
external damage is noted upon receipt of the package, please contact
Omega Engineering immediately.
Open the package from the top, taking care not to cut too deeply into the
package. Remove all the documentation and contents. Take care to
remove all the items and check them against the packing slip. The
products should also be checked for any concealed shipping damage. If
any shortages or damage is noted, please contact Omega Engineering to
resolve the problem.
Contents of Box- Sensor, Calibration Certificate & Manual
FMA 3100 Series shown; FMA 3300 series has an integrated display.
Caution: Take care not to
drop
your sensor. Read the
installation section of this manual before providing power or
tubing connections to the unit. Any damage caused by improper
installation or careless handling will not be repaired under
warranty (see limited warranty on page 28 for more details).
2. Product Overview and Principle of Operation
The FMA 3100/3300 Series flow sensors and flow meters from Omega
Engineering are capable of measuring virtually any clean, dry gas as low
as 0-20 sccm or as high as 0-500 l/min. Repeatable results are achieved
using a patented thermal mass flow sensor design. This proven design
M-4270/0707, pg. 4 of 29
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minimizes zero drift while maintaining fast response and linear outputs
with virtually no maintenance.
The FMA 3100/3300 Series utilizes
thermal sensing technology. A portion
of the gas flowing through the unit is
redirected into a small sensor tube.
This tube has two coils on the
outside. The first coil introduces a
small amount of heat into the gas
stream. As the gas passes through
the tube, heat is transferred from one
coil to the other. The flow rate is
proportional to the amount of heat
transfer. Smart electronics analyze
the amount of temperature change in
the second coil and provide a
linearized analog output. A patented
system insures that the zero remains
stable and the sensor is extremely
repeatable.
The output of the thermal mass flow sensor is directly related to the
specific heat characteristic of the gas being measured. A sensor is
calibrated for one gas but may be used with other gases by applying a
correction factor to the output. The calibration gas for each specific flow
sensor or flow meter is detailed on the product label.
B. Installation
1. General Considerations
It is recommended that a safety shut-off valve be installed upstream
(before) of the sensor.
All wetted parts should be checked for compatibility with the gas to be
used. If there are any incompatibilities e.g. highly corrosive gas, then the
unit may be damaged or fail prematurely. Such damage will not be
repaired under warranty.
Units should be installed in a clean, dry environment with an ambient
temperature that is as stable as possible. Avoid areas with strong magnetic
fields, strong air flows or excessive vibration.
Pressure drop across the FMA 3100/3300 Series is approximately 0.08 psi
(6 millibar) at 100% of the rated flow.
Caution: Do not exceed the pressure, temperature or power
operating ranges detailed in the SPECIFICATIONS section of this
manual. Omega Engineering shall not be liable for any damage
or injury caused by incorrect operation of their products.
M-4270/0707, pg. 5 of 29
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Pressure Drop vs. Percentage of the Full Scale
Rated Flow for the FMA 3100/3300 Series
0.08
0.07
0.06
0.05
0.04
PSID
0.03
0.02
0.01
0
0 102030405060708090100
% of Full Scale Rated Flow
Typical Pre ssure Drop
6
5
4
3
2
1
0
2. Mounting the Flow Sensor or Flow Meter.
The FMA 3100/3300 Series sensors have no particular orientation
requirements so may be mounted in any convenient position.
It is recommended that units be fixed to a suitable substrate using the two
4-40 mounting holes provided.
Mounting View from Bottom
(mounting hardware not included with sensor)
Bar
M-4270/0707, pg. 6 of 29
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3. Tubing Connections
a) General
All tubing must be clean, dry and purged with clean dry air before
installation of the flow sensor or flow meter.
If the gas to be used may contain particles then a filter (20 microns or
less) should be installed upstream of (before) the unit.
Caution: Use only the fittings factory installed on the unit. If the
fittings are removed the calibration of the unit may be effected
and leaking may occur. If different fittings are required please
contact Omega Engineering for assistance.
When connecting the sensor to the tubing, take care not to over-tighten
the fittings or leaking may occur.
b) High Flow Units (0-100 L/min and above)
It is recommended that tubing with a 0.5” (12.7 mm) outside diameter,
0.40” – 0.42” (10.16 mm – 10.67 mm) inside diameter is used. Using any
other tube size may effect the calibration.
High flow units should be installed with at least a 5” (127 mm) long
straight length of tube immediately before the sensor. For flow rates
above 200 L/min a straight length of at least 22” (559 mm) is
recommended. Using lengths shorter than these recommendations will
effect the calibration of the unit.
The manufacturer is able to calibrate high flow units for specific tubing
configurations. Please contact Omega Engineering for further details.
4. Electrical C onnections
Caution: Incorrect wiring may cause severe damage to the unit.
Applying an AC voltage (115VAC or 230VAC) directly to the unit
will cause damage. Read the following instructions carefully
before making any connections.
a) Overview
The FMA 3100/3300 Series provides a 0-5VDC analog output proportional
to the flow rate. This output may be connected to a display, data
acquisition system or voltmeter with an impedance of greater than 2.5 kΩ
(kilo ohms).
A stable D.C. power supply is required to operate the unit. The voltage
and current requirements depend on the configuration of the unit. Full
details may be found in the Specification section of this manual.
M-4270/0707, pg. 7 of 29
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Connecting wires should be as short as possible to avoid voltage drops.
Twisted conductor cable should be used if the length of the wiring is to be
longer than 2 meters.
Units are supplied with either a 6 pin mini DIN type connector (requires
mating cable assembly), a 9 Pin D Sub connector or 15 Pin D Sub
connector.
Caution: Cutting off the integrated connectors on the unit IS
NOT RECOMMENDED and will void the product warranty. Mating
cables should be ordered for each unit.
b) Connecting To The 6 Pin Mini Din Connector
Using a suitable mating connector the pins of the integrated connector
should be wired as follows:
Connecting To The Integrated 6 Pin Connector
Pin Numbers For
Integrated Connector
Pin 2 should be connected to the Positive of the power source.
Pin 6 should be connected to the Negative (Ground) of the power source.
Pin 3 provides the signal output and should be connected to the positive
terminal of the display, data acquisition system or voltmeter.
PIN 1 is the signal negative (ground) and should be connected to the
negative (Ground) terminal of the display, data acquisition system or
voltmeter.
On the integrated 6-pin connector, PINS 4 & 5 are unused.
Caution: Do not short the output signal pins or allow them to
contact the power wires at any time. DAMAGE WILL RESULT!
M-4270/0707, pg. 8 of 29
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c) Connecting The 6 P in Mini Din Connector and FMA 3 000C
Cable
The two mating connectors should be pushed together and the pigtail
leads wired as follows:
Connecting To The Integrated 6 Pin Connector Using A FMA 3000C Cable
The pigtail lead of the FMA 3000C cable assembly should be connected as
follows:
The RED wire (Pin 2 on connector) should be connected to the Positive of
the power source.
The BLACK wire (Pin 6 on the connector) should be connected to the
Negative (Ground) of the power source.
The ORANGE wire (Pin 3 on the connector) provides the signal output
and should be connected to the positive terminal of the display, data
acquisition system or voltmeter.
The BROWN wire (PIN 1 on the connector) is the signal negative
(ground) and should be connected to the negative (Ground) terminal of
the display, data acquisition system or voltmeter.
On the FMA 3000C cable, the GREEN and YELLOW wires, if present, are
unused. On the integrated 6-pin connector, PINS 4 & 5 are unused.
The wire colors above describe the pigtail leads of the 50-C-X cable
assembly and may not correspond with the internal wiring of your flow
sensor.
Caution: Do not short the output signal wires or allow them to
contact the power wires at any time. DAMAGE WILL RESULT!
M-4270/0707, pg. 9 of 29
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d) Connections For The 9 Pin D Sub Connector
Using a suitable mating connector the pins should be wired as follows:
Connecting To The Integrated 9 Pin Connector
Pin Numbers For
Integrated Connector
PIN 3 should be connected to the Positive of the power source.
PIN 4 should be connected to the Negative (Ground) of the power source.
PIN 2 provides the signal output and should be connected to the positive
terminal of the display, data acquisition system or voltmeter.
PIN 8 is the signal negative (ground) and should be connected to the
negative (Ground) terminal of the display, data acquisition system or
voltmeter.
Pins 1, 5, 6, 7 and 9 are not used.
Caution: Do not short the output signal pins or allow them to
contact the power connections at any time. DAMAGE WILL
RESULT!
M-4270/0707, pg. 10 of 29
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e) Connections For The 15 Pin D Sub Connector
Using a suitable mating connector the pins should be wired as follows:
Connecting To The Integrated 15 Pin Connector
Pin Numbers For
Integrated Connector
PIN 7 should be connected to the Positive of the power source.
PIN 5 should be connected to the Negative (ground) of the power source.
PIN 2 provides the signal output and should be connected to the positive
terminal of the display, data acquisition system or voltmeter.
PIN 10 is the signal negative (ground) and should be connected to the
negative (Ground) terminal of the display, data acquisition system or
voltmeter.
Pins 1, 3, 4, 6, 8, 9, 11, 12, 13, 14, and 15 are not used.
Caution: Do not short the output signal pins or allow them to
contact the power connections at any time. DAMAGE WILL
RESULT!
M-4270/0707, pg. 11 of 29
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f) Using a 0-5VDC Output Power Adapter Package.
An optional 0-5VDC Output Power Adapter Package is available for use
with the FMA 3100/3300 series. This consists of a power source (115VAC
or 230VAC), a connection hub and cable assembly with pig-tail (soldered
wire) ends. This should be assembled as shown in the following diagram.
Assembling an FMA 3115PW Power Adapter Package
(the FMA 3230PW Power Adapter Package is similar)
A 0-5VDC analog output proportional to the flow rate may be made
available by connecting the cable assembly to the connection hub. This
output may then be connected to a display, data acquisition system or
voltmeter with an impedance of greater than 2.5 kΩ (kilo ohms).
The RED wire of the cable assembly provides the signal output and should
be connected to the positive terminal of the display, data acquisition
system or voltmeter.
The COPPER/BARE wire of the cable assembly is the signal negative
(ground) and should be connected to the negative (Ground) terminal of
the display, data acquisition system or voltmeter.
Caution: Do not short the output signal wires or allow them to
contact the power wires at any time. DAMAGE WILL RESULT!
M-4270/0707, pg. 12 of 29
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C. Operation
1. Warm Up
Before applying power to the unit check all tubing and electrical
connections. Once correct installation is verified, you may switch on the
power. The unit should then be allowed to warm up for 5 minutes.
2. Verif icat ion of Ze ro
Flow through the unit should be stopped by sealing or capping the inlet of
the sensor. It is not adequate to only stop flow by turning off the gas
supply or closing a valve as there may be a leak in the system. This would
give a false reading.
After 5 minutes, the zero should be stable when there is no flow through
the unit. If after 10-15 minutes the output is still not zero volts (within
±0.5 volts) the unit should be adjusted as detailed in section C part 4.
It should be noted that power supply voltage variations and changes in
ambient temperature can have an effect on zero readings.
3. Flow Readings
Each sensor is factory calibrated for a specific flow range and gas (or gas
mixture). The calibration gas and flow range are shown on the unit’s label
and calibration certificate.
By monitoring the voltage output signal it is possible to determine the flow
rate of the gas. Units are configured so that an output signal of 5.0VDC is
provided when the maximum flow (i.e. Full Scale flow) is passing through
the unit. The output signal is linear and scaleable enabling calculation of
flow rates with in the sensor’s range. For example:
For a flow range of 0-500sccm:
At 500sccm the output signal would be 5VDC
If the output signal is 3.5VDC then the flow rate would be:
500 ÷ 5 × 3.5 = 350sccm
If the maximum flow rate is exceeded non-linear and inaccurate readings
will result.
Units may be used for gases other than the calibration gas. In this case a
“K Factor” would need to be applied and a corrected value calculated using
the following formula:
M-4270/0707, pg. 13 of 29
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/ Q2 = K1 / K2
Q
1
Q1 is the flow rate of the new gas
is the flow rate of the original calibration gas
Q
2
K
is the K factor of the new gas
1
is the K factor of the original calibration gas
K
2
Q
= (K1 / K2) Q2
1
If K
is larger than K1 then linear results will only be achieved if the unit
2
does not exceed 5(K
The accuracy of readings using K factors is not as good as that achieved
for the calibration gas. The accuracy obtained (typically ±3% for K factors
similar to the calibration gas) depends on the gas being used and the flow
rate.
For a list of common K Factors see Section J.
Example 1
For a 0-200sccm unit calibrated for air the flow at 5.0VDC would be
200sccm. The K factor for air is 1. If the unit is used with Helium (K factor
1.454 relative to air) then the flow at 5VDC (i.e. the maximum flow) would
be (1.454/1)200 = 290.8 sccm
Example 2
For a 0-50.0 l/min unit calibrated for Argon the flow at 5.0VDC would be
50.0l/min. The K factor for Argon is 1.45. If the unit is used with Carbon
Dioxide (K factor 0.74) then the flow rate 5.0VDC would be
(0.74/1.45)50.0 = 25.5l/min
4. Zero Adjustments
The zero should be checked as detailed in section C part 2. If an
adjustment is needed the Zero Potentiometer should be carefully turned
using a small flat head screwdriver until the output (VDC) becomes zero.
Caution: Do NOT adjust the Gain Potentiometer when adjusting
the zero or the unit will need to be recalibrated.
Care should be taken to only make small adjustments to the zero
potentiometer. If too much of an adjustment is made and difficulties are
being experienced in achieving a zero reading then turn the potentiometer
fully anti-clockwise and begin making small clockwise adjustments until a
zero reading is obtained.
/ K2)VDC for the full scale output.
1
M-4270/0707, pg. 14 of 29
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Making Zero Adjustments Using a Small Flathead Screwdriver
5. Recalibration
If recalibration is required please contact Omega Engineering.
D. Maintenance and Product Care
1. General
Inlet filters should be periodically checked and cleaned or replaced as
necessary.
Regularly check all electrical and process connections for damage or
deterioration.
If the sensor is to be stored, keep both the inlet and outlet ports sealed.
Do not allow any liquid or moisture to enter the sensor or damage will
occur.
2. Returning Units for Repair or Recalibration
To return a unit for repair or recalibration please contact the Omega
Engineering Customer Service Department. An Authorized Return (AR)
number will then be issued. The AR number should then be noted on the
outside of the package and on any correspondence. Further details may be
found on page 28 of this manual.
M-4270/0707, pg. 15 of 29
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E. Specifications
FMA 3100 FMA 3300 FMA 3100ST FMA 3300ST
Accuracy
(including linearity)
Repeatability ±0.25% Full Scale*
Pressure Rating 150 psig (10.3 bar) 500 psig (34.5 bar)
Pressure Sensitivity ±0.02% Full Scale* per psi (per 69 mbar)
Temperature Rating Operating Range: 5 to 55ºC
Recommended Range (for best performance) : 10 to 40ºC
Temperature
Sensitivity
Leak Integrity 1x10-7 sccs of He
Wetted Materials Aluminum
304 Stainless Steel
316 Stainless Steel
O-Ring Material Viton® N/A
Fitting Material Choose from acetal, brass, or stainless steel
Recommended
Filtration
±1.5% Full Scale*
Storage Range: 0 to 70ºC
±0.15% F.S.* or less per ºC
303 Stainless Steel
304 Stainless Steel
316 Stainless Steel
Epoxy
20 microns or less
Optional inline filters available
Compatible gases Clean, dry gases compatible with wetted materials
0-5 VDC Output
Signal
Warm-Up Time Less than 5 minutes
Integrated Display N/A 3½ digit N/A 3½ digit
Typical Power
Consumption
Peak Power
Consumption
Electrical Connections Integrated 36” (92 mm) cable, terminated with:
Settling Time Typically <1 second for 97% of final value
Reliability 100,000 Hours MTBF (testing ongoing)
Certifications CE Approved
Ratings IP10 (NEMA 1)
Impedance of greater than 2.5 KΩ
Standard: 12 VDC @ 100 mA (12.5-15 VDC)
“E” Suffix: 24 VDC @ 80 mA (22-25 VDC)
Standard: 12 VDC @ 180 mA (12.5-15 VDC)
“E” Suffix: 24 VDC @ 160 mA (22-25 VDC)
Standard: 6-pin Mini-DIN male (PS/2 Style)
D1 Option: 9-pin D-Sub male
D2 Option: 15-pin D-Sub male
89/336/EEC (EN 55011 & EN 50082-1)
73/23/EEC Low Voltage Directive
*Specifications from 10-100% of rated flow. Linearity is best fit straight line. All calibrations
performed with air unless otherwise stated on calibration certificate.
M-4270/0707, pg. 16 of 29
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F. Dimensions
ALL DIMENSIONS IN INCHES (MILLIMETERS IN BRACKETS)
FMA 3100 - 0-500 sccm Flow Ranges and Below
¼” Stainless Fittings Shown
M-4270/0707, pg. 17 of 29
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FMA 3100 - 0-1000sccm Up To 0-10 L/min &
FMA 3100ST - All Ranges Up To 0-10 L/min
¼” Stainless Fittings Shown
M-4270/0707, pg. 18 of 29
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FMA 3100 / 3100ST - 0-20 L/min up to 0-100 L/min
3/8” Stainless Fi ttings S hown
M-4270/0707, pg. 19 of 29
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FMA 3100 – 0-200 L/min and 0-500 L/min
½” Stainless Fittings Shown
M-4270/0707, pg. 20 of 29
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FMA 3300 – Flow Ranges Up To 0-500sccm
¼” Stainless Fittings Shown
M-4270/0707, pg. 21 of 29
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FMA 3300 - 0-1000sccm Up To 0-10 L/min &
FMA 3300ST - All Ranges Up To 0-10 L/min
¼” Stainless Fitti ngs Shown
M-4270/0707, pg. 22 of 29
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FMA 3300 / 3300ST - 0-20 L/min up to 0-100 L/min
3/8” Stainless Fi ttings S hown
M-4270/0707, pg. 23 of 29
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FMA 3100 – 0-200 L/min and 0-500 L/min
½” Stainless Fitti ngs Shown
M-4270/0707, pg. 24 of 29
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G. Gas K Factors
Gas
Acetylene C2H2 0.589
Air - 1.000
Argon Ar 1.438
Butane C4H10 0.260
Carbon Dioxide CO2 0.739
Deuterium D2 1.000
Ethylene C2H4 0.598
Freon 11 CCL3F 0.330
Freon 12 CCL2F2 0.354
Freon 13 CCLF3 0.385
Freon 14 CF4 0.420
Freon 22 CHCLF2 0.460
Germane GeH4 0.570
Helium He 1.458
Hydrogen H2 1.011
Krypton Kr 1.440
Methane CH4 0.721
Neon Ne 1.443
Nitric Oxide NO 0.990
Nitrogen N2 1.000
Nitrous Oxide N2O 0.710
Oxygen O2 0.991
Ozone O3 0.446
Propane C3H8 0.383
Sulfur Dioxide SO2 0.690
Xenon Xe 1.437
These K Factors are given for reference only and are not intended as a
recommendation of application suitability. Accuracy and response will be
affected depending on the gas and flow range. Check the compatibility of all
wetted materials before using any gas other than the calibration gas for the
unit.
Chemical
Symbol
K Factor
M-4270/0707, pg. 25 of 29
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H. Troubleshooting Guide
Symptom Possible Cause Method of Correction
No response
Inaccurate readings
Unit wired incorrectly Check wiring is according to
Section B5
Loose connection Check all connectors and
wiring
Damaged connector pins Contact Omega Engineering
Blocked flow path Check flow path for
obstructions.
Piping leak before sensor Check all piping and
connections.
Insufficient power Check the power supply
output and increase if
necessary
Output load resistance too
low
Flow too low for the unit Ensure that the flow being
Unit damaged or faulty Contact Omega Engineering
Particles in flow path Add filtration before the
Flow path obscured Remove any debris or
Unit calibrated for a
different gas
Gas composition is variable Contact Omega Engineering
Fittings have been changed Replace the factory installed
Moisture in gas Ensure gas is clean and dry
Insufficient warm-up period Allow the unit to warm-up
Zero drift Verify the zero and adjust as
The gain potentiometer has
been adjusted
Unit needs recalibration Contact the Omega
Flow too high for the unit Ensure that the flow being
Ensure the voltmeter or data
acquisition system or display
has an impedance of greater
than of 2.5kohm
measured is within the
capabilities of the unit
sensor.
blockage in the flow path eg.
PTFE tape.
Check calibration certificate
and apply a “K” Factor to
readings if necessary.
fittings
for at least 5 minutes.
necessary as explained in
Section C
Contact the Omega
Engineering
Engineering
measured is within the
capabilities of the unit
M-4270/0707, pg. 26 of 29
Page 27
Symptom Possible Cause Method of Correction
Inaccurate Readings
Problems with rezeroing
Output load resistance too
low
Insufficient power Check the power supply
Ambient temperature too
high or too low
Gas temperature too high
or too low
Unit damaged or faulty Contact Omega Engineering
Gas flow through unit not
completely stopped
Severe fluctuations in the
ambient temperature e.g.
unit in direct sunlight
Unstable power supply Check the stability and
Insufficient warm-up
period
Ensure the voltmeter or data
acquisition system or display
has an impedance of greater
than of 2.5kohm
output and increase if
necessary
Place the unit in a suitable
environment
Ensure the gas temperature is
within the recommended
operating range
Ensure there is no flow
through the unit. The easiest
way to do this is to plug both
the inlet and outlet.
Carry out the rezero
procedure in a stable
environment
suitability of the power source
Allow the unit to warm-up for
at least 5 minutes.
M-4270/0707, pg. 27 of 29
Page 28
M-4270/0707, pg. 28 of 29
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M-4270/0707, pg. 29 of 29
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