Section 2.12.1 ECB Responsibilities

Section 2.12.1 ECB Responsibilities
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
July 1, 2015
Page 1 of 52
National Core (NCore) and State and Local Air Monitoring Station
(SLAMS) Meteorological Monitoring QA Plan
Section I
Electronic Calibration Branch Responsibilities
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
July 1, 2015
Page 3 of 52
Table of Contents
2.12.1 National Core (NCore) & State and Local Air Monitoring Station (SLAMS)
Meteorological Monitoring QA Plan: ECB Responsibilities.............................................. 4
2.12.1.1
Meteorological Monitoring Equipment .................................................................... 5
2.12.1.1.1
MET One Model 010C Wind Speed Sensor ............................................................. 6
2.12.1.1.1a Wind Speed Calibrations ........................................................................................ 11
2.12.1.1.2
MET One Model 020C Wind Direction Sensor ..................................................... 15
2.12.1.1.2a Wind Direction Calibration..................................................................................... 20
2.12.1.1.3
R. M. Young Model 05305AQ Wind Speed / Wind Direction .............................. 23
2.12.1.1.3a Wind Speed Calibrations ........................................................................................ 26
2.12.1.1.3b Wind Direction Calibrations ................................................................................... 27
2.12.1.1.4
Climatronics Model CS800-L Wind Speed / Wind Direction ................................ 27
2.12.1.1.4a Wind Speed Calibrations ........................................................................................ 28
2.12.1.1.4b Wind Direction Calibrations ................................................................................... 29
2.12.1.1.5
Campbell Model HC2S3 Relative Humidity .......................................................... 30
2.12.1.1.5a Relative Humidity Calibration ................................................................................ 32
2.12.1.1.6
Met One Model 083C Relative Humidity Sensor ................................................... 34
2.12.1.1.6a Relative Humidity Calibration ................................................................................ 35
2.17.1.1.7
MET One Model 062 Temperature......................................................................... 38
2.12.1.1.7a Temperature Calibration ......................................................................................... 39
2.12.1.1.8
Campbell Model HC2S3 Temperature ................................................................... 40
2.12.1.1.8a Temperature Calibration ......................................................................................... 42
2.12.1.1.9
SU-100 UV Solar Radiation Sensor ....................................................................... 45
2.12.1.1.9a Solar Radiation Calibration..................................................................................... 47
2.12.1.2
Data Logger Channel Procedure ............................................................................. 47
2.12.1.3
Site Visits ................................................................................................................ 48
2.12.1.4
Accuracy Audits...................................................................................................... 49
2.12.1.5
Data Acquisition ..................................................................................................... 49
2.12.1.6
MET Parameter Shutdown Procedure .................................................................... 50
Table of Figures
Figure 1
Figure 2
Figure 3
Figure 4
Wind Speed Cal / Audit Sheet ...................................................................................... 14
Wind Direction Cal / Audit Sheet ................................................................................ 23
Relative Humidity Cal / Audit Sheet ............................................................................ 37
Ambient / Delta Temperature Cal / Audit Sheet .......................................................... 44
List of Tables
Table 1 Database Screening Criteria........................................................................................... 51
Table 2 NCore Meteorological Calibration and Accuracy Criteria ............................................ 51
Table 3 State and Local Air Monitoring Station (SLAMS) Meteorological Calibration and
Accuracy Criteria ........................................................................................................... 52
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
July 1, 2015
Page 4 of 52
2.12.1
National Core (NCore) & State and Local Air Monitoring Station (SLAMS)
Meteorological Monitoring QA Plan: ECB Responsibilities.
Note: The following is a list of "significant changes" from Revision 1.4.
1) QA updated per QAP/SOP 2.39 "Standard Operating Procedure (SOP) for Preparing Quality
Assurance Plans/SOPs".
2) Project and Procedures Branch updates.
3) State and Local Ambient Monitoring (SLAMS) meteorological monitoring requirements
added.
4) EDAS language removed and AvTrend language added.
The U.S. EPA is currently implementing the National Ambient Air Monitoring Strategy
(NAAMS). The NAAMS goals include improvement of the scientific and technical competency
of the nation’s air monitoring networks and increased value in protecting public health and the
environment.
The North Carolina Ambient Meteorological Monitoring System must meet or exceed the
requirement that meteorological data collected at all NCore stations, as stated in the Code of
Federal Regulations (CFR) Chapter 40 Section 58, Appendix D.3.b. Effective January 1, 2011,
two (2) meteorological calibrations are required per year at all NCore stations. The NC ambient
meteorological monitoring system consists of the following:
1.
2.
3.
4
5.
6.
7.
8.
9.
8.
Met One Model 010C Wind Speed Sensor
Met One Model 020C Wind Direction Sensor
R M Young Model 05305AQ Wind Speed/Wind Direction Sensor
Climatronics Model CS880-L Wind Speed/Wind Direction Sensor
Campbell Model HC2S3 Relative Humidity/ Temperature Sensor
Met One Model 083C Relative Humidity Sensor
Vaisala Model HMP45AC Relative Humidity/ Temperature Sensor
Met One Model 062 Temperature Sensor
Campbell Model HC2S3 Temperature Sensor
Apogee SU-100 UV Solar Radiation
Note: minor components are not specified but included by reference.
The ECB is responsible for ensuring that all components are compatible with the meteorological
measurement devices. The ECB also performs audits and calibrations as needed. The ECB is
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
Monitoring QA Plan
Section 2.12.1
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responsible for the performance of complete system evaluation prior to the field installation and
that the system is fully functional at the completion of the installation. On an ongoing basis as
needed the ECB provides equipment and instrumentation maintenance and operational support to
maximize the collection of the highest quality ambient air pollution data possible in accordance
with accepted and approved procedures.
The Quality Assurance Handbook for Air Pollution Measurement Systems Vol. IV:
Meteorological Measurements Version 2.0 (Final) is designed to provide clear and concise
information and guidance to the State/Local/Tribal (SLT) air pollution control agencies that
operate meteorological monitoring equipment and systems. Recently, the new monitoring rule
was published, which establishes the requirements for meteorological monitoring in support of
National Core (NCore) and State and Local Ambient Monitoring Station (SLAMS) network for
items such as ambient temperature, relative humidity, wind speed and wind direction. Other
requirement items such as barometric pressure, precipitation and upper-air meteorology will not
be discussed in this document.
Note: The meteorological monitoring for the State and Local Air Monitoring Station (SLAMS)
sites will follow the NCore requirements with the exception of sensor acceptance criteria
(relative humidity and ambient temperature) and calibration frequency.
2.12.1.1
Meteorological Monitoring Equipment
Selection and Procurement
The Electronics and Calibration Branch (ECB) of the Ambient Monitoring Section of the
Division of Air Quality (DAQ) is responsible for the evaluation and procurement of ambient
pollution monitoring equipment; installation of monitoring instrumentation, samplers, and
support equipment; evaluation of the on-going performance of all state operated air pollution
sampling and monitoring systems; and scheduled and unscheduled system maintenance. The
ECB maintains a sufficient inventory of monitoring system instrumentation, support equipment,
and replacement parts to minimize the loss of ambient air monitoring data for all ambient air
monitoring equipment of the Ambient Monitoring Section.
The ECB is also responsible for procuring and maintaining dedicated traceable standards for the
certification of all calibrators and the independent accuracy auditing of ambient air quality
monitoring systems. These standards provide a direct link to established national standards and
are the foundation for the collection of the highest quality ambient air pollution data possible in
accordance with current procedures and existing Federal Regulations and Guidelines. The
accuracy audits performed by ECB provide an ongoing evaluation of monitoring equipment
performance and site operator adherence to approved operating procedures. The ECB maintains
permanent records on all standards used in the calibration and auditing of all instrumentation and
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
Monitoring QA Plan
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sampling equipment used in support of DAQ monitoring activities.
The ECB maintains permanent records for each meteorological site used to monitor ambient air
quality in the state of NC. Each significant component of the meteorological monitoring system
(wind direction sensors, wind speed sensors, temperature sensors, and relative humidity sensors)
is assigned a dedicated unique (data logger) logbook. These logbook records include the
complete repair records for the site instrumentation. These permanent records are updated
continuously.
The ECB is also responsible for evaluating, developing, and recommending changes in
equipment and operating parameters to improve the quality of data collected and procedures used
in the collection of the data.
All original records (records documenting observations, i.e. calibration and audit logbook) must
be legible, complete, dated, and signed by the operator and retained as part of the permanent
instrument calibration record. The operator’s signature on the calibration logbook form certifies
that the calibration has been performed in accordance with this QA/SOP and that the information
contained on the form is accurate. All records will be reviewed and verified by the ECB
Supervisor and audited by Raleigh Central Office.
2.12.1.1.1
MET One Model 010C Wind Speed Sensor
The wind speed sensor uses a three-cup anemometer assembly and solid-optical link with a 40slot chopper disk to produce a pulse output frequency proportional to the wind speed. An
internal heater reduces moisture to extend bearing life. This sensor is usually used in
conjunction with the 191 Cross arm Assembly. The sensor cable is connected directly to the data
logger. The following table summarizes the performance and electrical specifications:
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
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PERFORMANCE CHARACTERISTICS
Maximum Operating Range
0-125 mph or 0-60 meters/sec
Starting speed
0.6 mph or 0.27 meters/sec
Calibrated range
0-100 mph or 0-50 meters/sec
Accuracy
1% or 0.15 mph
Temperature range
-50ºC to +85ºC
Response
Distance constant less than 5 feet of flow*
* The distance traveled by a sharp wind gust for the anemometer to reach 63% of
the new wind speed value.
ELECTRICAL CHARACTERISTICS
Power requirements
12 VDC at 10 mA
Output signal
11-volt pulse
Output impedance
100 ohms maximum
Installation
a)
Mount the cup assembly and secure with the allen-head setscrew and check to see that the
cup assembly rotates freely.
b)
Install the sensor in the end of the Model 191 Mounting Arm (the end without the
bushing).
c)
Tighten the locking setscrews. Do not over tighten. Apply a small amount of silicone
grease to the setscrews to prevent freezing in corrosive environments.
d)
Connect the cable assembly to the keyed sensor receptacle and attach it to the mounting
arm. (Refer to Met One operations manual, 010C Wind Speed Sensor Fig. 2-1).
e)
Connect the six wires on the cable from the 2 meter and 10 meter wind speed sensors to
the ESC data logger. (Refer to Met One operations manual, Connections section drawing
SID-1019 and SID-1021).
f)
Weather sensors are sensitive to direct or nearby lightning strikes. A well-grounded
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
Monitoring QA Plan
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metal rod or frame should be placed above the sensor installation. In addition, the shield
on the signal cable leading to the translator must be connected to a good earth ground at
the translator end and the cable route should not be vulnerable to lightning.
Operational Check
a)
Spinning the anemometer cup assembly will produce output pulses (40 pulses per
revolution). To verify sensor output, monitor this signal with the translator module, data
logger or an oscilloscope. Spinning the anemometer hub without the cup assembly
mounted and allowing it to coast to a stop will give a good indication of the threshold
performance; a jerky or sudden stop indicates damaged bearings, bent drive shaft or
obstruction in the light chopper.
b)
Inspect the cup assembly for loose cup arms or other damage. The cup assembly cannot
change calibration unless a mechanical part has come loose or has been broken. If a cup
arm is loose or broken, the calibration of the sensor may be affected.
c)
Check the internal heater operation by sliding the sensor cover down and touching the
housing behind the printed circuit board. The housing should feel warmer than the
adjoining metal parts. The sensor has a built-in heater that is designed to provide a raise
in the internal temperature, providing a small positive pressure. This heater requires an
external 12V (@500ma) power supply.
Maintenance, 6-12 Month Interval
a)
At the cross arm assembly, disconnect the quick disconnect plug from the sensor (leave
the cable secured to the cross arm) and remove the sensor from the cross arm assembly.
b)
Loosen the setscrew holding the cup assembly. Support the rotating hub of the sensor
with one hand and pull the anemometer cup assembly free.
c)
Visually inspect the anemometer cups for cracks and breaks, and make sure each arm is
securely attached to the cup assembly hub.
d)
Slide the sensor cover down to expose the light chopper disc assembly, light source and
the detector and circuit board. Inspect the interior of the sensor for any signs of corrosion
and dust buildup. Inspect the light-chopper for cracks and make sure all slots are free of
corrosion. Inspect the signal conditioning module for cracks and corrosion around the
soldered connections. Repair or replace any bad components.
e)
Apply a small amount of silicone lubricant (Dow Corning DC-33 or equivalent) to the
sensor o-rings. Slide the cover up over the sensor and remove any excess lubricant.
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
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f)
A moisture vent is located on the base of the sensor; make sure this vent is clear.
g)
Reinstall the sensor and verify proper operation and sensor output per Section 2.12.1.1.1
Operational Check.
Maintenance, 12-24 Month Interval
a)
Recommend complete overhaul of sensor. This maintenance may be provided by the
factory or in-house. Section "b)" provides instructions for maintenance of the wind speed
sensor.
b)
Maintenance
The following procedures require a relatively clean, dry work area, a source of 12 VDC
power at approximately 20 mA, and an oscilloscope (DC to 10 Khz minimum range
required). The following sections assume the sensor has already been removed from the
tower and the cup assembly removed. Also, the appendix contains a list of parts for this
sensor.
c)
Sensor Bearing Replacement (Refer to Met One operations manual 010C Wind Speed
Sensor, Section, 4.4 and Table 4.2)
Disassemble the sensor and remove the old bearings by the following steps:
1.
2.
3.
4.
5.
6.
7.
8.
Slide the sensor cover (16) down to expose the light chopper assembly (11).
Loosen both special setscrews on the shaft of the light chopper assembly (11)
Support the light chopper assembly (10) with one hand and slowly pull the
rotating hub/shaft assembly (2) out of the assembly (8).
Remove the shield (4) and slinger (5) from the column (8).
Remove the light-chopper assembly (10) from the sensor housing, being careful
not to damage the slots located between the light chopper holder and the lower
bearing.
Insert the lower end of the rotating hub/shaft assembly into the upper bearing,
cock it slightly to one side and push out the lower bearing.
Insert a right-angle type of tool, such as an Allen wrench, into the upper bearing:
cock it slightly to one side and remove the bearing.
Clean dirt from the bearing using a cotton swab and alcohol.
Install the new bearings and assemble the sensor as follows:
1.
Install the new upper and lower bearings in the column (8). Bearings
should slide easily into the bearing bores.
Install the slinger and shield (4,5) on the column assembly. Replace the damaged
or corroded parts with new parts.
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Monitoring QA Plan
Section 2.12.1
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3.
4.
5.
6.
7.
8.
Insert the rotating hub shaft (2) into the column assembly (8) through the shield
(4), slinger and upper bearing, until it starts to protrude through the lower bearing.
Support the light-chopper assembly (10) with one hand and slowly push the
rotating hub shaft into it until the shaft almost bottoms.
Tighten both special setscrews on the light-chopper assembly, but do not over
tighten as the setscrews will damage the shaft.
Rotate the sensor hub assembly (2) to ensure it turns freely and the end play is
about 0.005.
Hold the sensor vertically and make sure the light-chopper assembly (10) is not
contacting the detector assembly (12).
Apply small amount of silicone lubricant (Dow Corning DC-33 or equivalent) to
the sensor O-rings and slide the cover (16) up over the sensor and remove any
excess lubricant.
d)
C1200 Circuit Board Assembly Replacement (Refer to Met One operations manual 010C
Wind Speed Sensor, Section 4.5, Table 4.2 and Drawing 1202)
1.
Slide the sensor cover (16) down to expose the light-chopper disc assembly (10),
detector assembly (12) and the circuit board (18).
2.
Remove the two screws (17) holding the circuit board assembly (18) and lift the
circuit board away from the sensor housing.
3.
Note the colors of each wire and unsolder the three wires to the detector assembly
from the circuit board and the three wires from the connector (19).
4.
Install new circuit board assembly by reversing the above steps and following the
wire color code.
e)
Detector Assembly Replacement (Refer to Met One operations manual 010C Wind Speed
Sensor, Section 4.6, Table 4.2 and Drawing 1202)
1.
2.
3
4.
5.
f)
Slide the sensor cover (16) down to expose the light-chopper disc assembly (10),
detector assembly (12) and the circuit board (18).
Remove the two screws (17) holding the circuit board assembly (18) and lift the
circuit board away from the sensor housing.
Note the color of each wire and unsolder the three wires to the detector assembly
from the circuit board (18).
Remove the two screws (20) holding the detector assembly (12) and remove the
assembly.
Install the new detector assembly and re-assemble by reversing the above steps
and following the wire color coding.
Integrated Amplifier Replacement (Refer to Met One 010C Wind Speed Sensor
operations manual, Section 4.6, Table 4.2 and Drawing 1202)
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
July 1, 2015
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1.
2.
3.
Slide the sensor cover (16) down to expose the light-chopper disc assembly (10),
detector assembly (12) and the circuit board (18).
Carefully pry the amplifier (23) from its socket on the circuit board
noting Pin 1 orientation.
Install replacement integrated amplifier by reversing the above steps,
being sure Pin 1 is properly oriented.
Model 010C Wind Speed Sensor Troubleshooting Chart
Symptom
Probable Cause
Solution
Loss of supply voltage
Check translator +12V
supply & connecting cables
Faulty integrated amplifier
Replace IC amplifier
Faulty diodes D1, D2
Replace circuit board
Faulty detector
Replace detector
No wind speed output below
2-5 mph
Bad bearings
Replace bearings
Faulty detector
Replace detector
Wind speed signal drops out
as speed increases
Faulty detector
Faulty detector
No wind Speed output
2.12.1.1.1a
Wind Speed Calibrations
Calibration Frequencies
Calibrations are required on the wind speed sensor at site startups, sensor repairs or adjustments
that will affect the response or data. Also calibrations are required after any unacceptable QA
audit. Bi-annual wind speed calibrations are required at all NCore sites, annually for non-NCore
sites. The audit and calibrations should be performed using different standards and
different personnel.
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
July 1, 2015
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Wind Speed Calibrations Devices
The wind speed calibration device is a Model 053 Wind Speed Calibrator. It consist of a variable
speed motor, a electronic control and display module, a sensor clamp assembly to mount the
motor and couplings to connect the motor to the shaft. The wind speed calibrator produces
known revolutions per minute (RPM) of shaft speed to the wind speed sensor. The shaft speed in
RPM’s is used to calculate the wind speed in meters per second.
The wind speed starting torque device is a Model 050 Torque Gauge. It consists of a balance
wheel and precision counter weights. The gauge is traceable to NIST MIL-STD-45662A
specifications.
Calibration Procedure
a)
The calibration begins by removing the wind speed anemometer cup assembly from the
sensor. The wind speed calibrator motor drive is then positioned on the sensor to spin the
wind speed sensor’s shaft. Care must be exercised to properly align the wind speed
calibrator motor drive directly over the shaft. This will prevent any strain to the
calibrator motor or the shaft. The coupling from the calibrator motor drive to the shaft
should be centered. Connect the calibrator motor drive cable to the electronic control
module. The calibrator is now ready to begin the calibration.
b)
The calibration speeds to calibrate a Met One 010C wind speed sensor are 0.0, 100, 200,
400 and 800 RPM. The 0.0 RPM is produced with the control module turned off. The
upscale points are generated with the control module turned on and the direction switch is
set on clockwise rotation. The push wheel switches are toggled to produce the desired
reading on the 4 digit LCD starting with the lowest setting first. The motor and control
module should stabilize within a one-minute period to the input setting. If the readout is
not within +/- 1 RPM on the control module LCD stop the audit and investigate problem.
Problem is usually improper alignment of motor drive or weak control module batteries.
Once the control module LCD is stable, view the data logger wind speed value. If data
logger wind speed reading is stable at this point record the value. Adjust the push wheel
switch for the next point and repeat measurement process. Continue the calibration until
all points are generated and the wind speed response is recorded from the data logger.
c)
Turn off the control module power, disassemble the motor drive and remove the sensor
clamp assembly. Remove the sensor cable from the wind speed sensor and remove the
sensor from the cross arm mount.
d)
Install the 050-torque balance wheel on the wind speed sensor shaft to verify the starting
torque. Screw a black nylon screw into the 2 cm position of the balance wheel. Lay the
sensor in a horizontal position and hold the balance wheel level. Release the balance
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
Monitoring QA Plan
Section 2.12.1
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wheel and watch for a downward deflection caused by the nylon screw. Rotate the wind
speed sensor 90 degrees and level balance wheel. Release the balance wheel and watch
for the deflection caused by the nylon screw. Repeat measurements until the sensor is
tested at four evenly spaced points around the sensor’s shaft. If there is no downward
deflections at any test points the counter weight must be increased by 0.1 gm-cm until
there is downward movement. Do not exceed 0.4 gm-cm counterweight since starting
torque specifications have been exceeded. Record the highest value tested.
e)
Reinstall the wind speed sensor to the cross arm mount and reconnect the signal cable.
Install the anemometer cups to the wind speed sensor. The wind speed calibration is now
complete.
f)
Calculate the calibration input values from the formula given below and found on the
field calibration form (see Figure 1, pg. 14). The calibration is considered acceptable if
each wind speed value is within +/- 0.5 meters per second from the calibration input
value. The audited sensor starting torque threshold is acceptable if all measured points are
less than 0.2 grams per centimeter. If any measurements do not meet the acceptable
specifications for a wind speed calibration the sensor must be evaluated by the technician.
The technician will examine the sensor, make necessary repairs and recalibrate the
sensor. The calibration data and recommendations will be included a calibration report.
Calibration Input Wind Speed m/sec = rpm * 0.00512
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
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Figure 1 Wind Speed Cal / Audit Sheet
Wind Speed: Calibration
Audit _____
Site __________
Start Time ____________
Sensor Model ____________
Torque Gauge ____________
Calibration Device ____________
RPM
Date __________
Stop Time ____________
Sensor SN____________
Device SN ____________
Device SN ____________
Input Speed
(m/sec)
Data logger speed
(m/sec)
Difference
0.0
100.0
200.0
400.0
800.0
Measured Sensor Torque gms/cm
Specifications __________
Calibration Wind Speed meters / second =
MET One 010C sensor / RM Young 05305AQ
RM Young 18801 cross-arm
rpm * 0.00512
RPM


42.55


 + 0.2235

Difference = Data logger speed - input speed
Acceptable:
Yes
No
Auditor ___________
Each single point measurement must be within ±0.25m/s ≤5m/s; 5%>2m/s not to exceed 2.5m/s
of input value for calibration to be acceptable (NCore and SLAMS)
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
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2.12.1.1.2
MET One Model 020C Wind Direction Sensor
The wind direction sensor uses a lightweight airfoil vane and a micro torque potentiometer to
produce an analog output proportional to the wind direction. An internal heater reduces moisture
for extended bearing life. The sensor is used in conjunction with the 191 Cross arm Assembly.
This sensor is connected to the data logger using the 2465 sensor cable. The following table
summarizes the performance and electrical specifications:
PERFORMANCE CHARACTERISTICS
Azimuth
Electrical 0 – 356º
Mechanical 0 – 360º
Threshold
0.6 mph
Linearity
± 0.5% of full scale
Accuracy
± 2º
Damping Ratio
0.4 - 0.6
Delay Distance
less than 3 feet
Temperature range
-50ºC to +85ºC
ELECTRICAL CHARACTERISTICS
Input Power (+VRef)
5VDC (max) with 5 mA current
limiting
Output
Varying resistance 0-10k ohms
Maximum line length
1500 feet
Heater power requirement
12VDC at 350 mA
National Core (NCore) and State and Local Air Monitoring Station (SLAMS) Meteorological
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Section 2.12.1
Revision No. 1.5
July 1, 2015
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Installation
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
l)
m)
Install the vane assembly on the sensor (note the locator pin fits into the slot in the vane
assembly hub) and tighten the setscrew. Do not over tighten. (Refer to Met One 020C
Wind Direction Sensor operations manual, Section 2.1, Table 4-3, Fig. 2-1, and Drawing
2465).
Check to see if the vane assembly rotates freely.
Ensure the vane assembly is properly balanced and the balance counterweight is tight.
Install the sensor in the Model 191 Mounting Arm with the keyed bushing. The
orientation screw on the stem of the wind direction sensor will fit into the hole on the
mounting bushing.
The aluminum fitting has two recessed setscrews that may require tightening to further
secure the sensor. Over-tightening these screws may strip out the head, making it
virtually impossible to remove. Apply a small amount of silicone grease to prevent
freezing in corrosive environments.
Connect the cable assembly to the keyed sensor receptacle and attach it to the mounting
arm.
Model 020C Wind Direction Sensor Alignment (Refer to Met One operations manual
020C Wind Direction Sensor, Section 2-2, Table 4-3, Fig. 2-1 and Drawing 2465). The
orientation pin located on the stem of the sensor is to be oriented so it points true south.
This means that the wind direction orientation must account for the difference between
magnetic and true north.
Tape the sensor hub and column together so the notches on each part are exactly aligned.
Loosen the two setscrews in the aluminum fitting so the sensor and mounting bushing
may be rotated.
Rotate the sensor so the vane (counter-weight end) points directly south. A transit located
directly south or north will facilitate the alignment process. Merely rotate the sensor until
the vane (counter weight and sensor column) point south.
Tighten the two setscrews in the aluminum fitting and remove the orientation device.
Apply a small amount of silicone grease to the screws to prevent freezing in the
aluminum fitting. The sensor may now be removed and re-installed at any time without
requiring orientation.
Connect the five wires on the cable from the 2 meter and 10 meter wind direction sensors
to the ESC data logger.(Refer to Met One operations manual 020C Connections Section,
SID-1020 and SID-1022).
Weather sensors are sensitive to direct or nearby lightning strikes. A well-grounded
metal rod or frame should be placed above the sensor installation. In addition, the shield
on the signal cable leading to the translator must be connected to a good earth ground at
the translator end and the cable route should not be vulnerable to lightning.
Operational Checkout
a)
With the sensor connected to the input, any movement of the vane in a clockwise
direction (as seen from above) will result in a positive voltage output. Movement of the
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sensor’s output will progress up-scale until it reaches + Vref, then the output voltage will
drop to 0 volts. Continued clockwise rotation will again bring the module’s output
voltage to +Vref and the action can be repeated. When the notch on the hub and the
column of the sensor are exactly aligned, the output signal will correspond to 180º or
50% of Vref.
b)
Check the internal heater operation by sliding the sensor cover up and touching the
housing. The housing should feel warmer than the adjoining metals parts.
Maintenance, 6-12 Month Interval
a)
At the cross arm assembly, disconnect the quick disconnect connector from the sensor
(leave the cable secured to the cross arm). Remove the sensor from the cross arm
assembly bushing. (Refer to Met One operations manual 021C Wind Direction Sensor,
Section 4.2, Table 4-3, Fig. 2-1, and Drawing 2465).
b)
Support the rotating hub of the sensor with one hand and pull the vane assembly free.
c)
Visually inspect the wind vane assembly to ensure the wind vane and counterweight are
securely attached to the wind vane rod, and the setscrew in the rotating hub holds the rod
in place.
d)
Carefully slide the sensor cover down to expose the potentiometer assembly. Inspect the
interior of the sensor for any signs of corrosion. Also, inspect the potentiometer for loose
wires, cracks and corrosion.
e)
Inspect the shaft coupler for proper position. Make sure the marks on the rotating hub
and the column assembly are aligned and all four special setscrews are tight.
NOTE: Any time the coupler assembly is moved in relation to the shaft, the
potentiometer alignment must be performed.
f)
Rotate the sensor hub assembly to make sure it turns freely and the sensor bearings are
not damaged. If rotation is not free, inspect the bearings and replace if necessary.
g)
Check to ensure the potentiometer assembly is rigid in its holder.
h)
Check the sensor O-rings for cracks. Replace as necessary. Apply a small amount of
silicone lubricant (Dow Corning DC-33 or equivalent) to the sensor O-rings seals. Slide
the cover over the sensor and wipe off any excess lubricant.
i)
Support the rotating hub of the sensor with one hand and mount the wind vane assembly
on the hub. The wind vane assembly is keyed to fit the pin on the hub. Make sure the
moisture vent located on the base of the sensor is unobstructed.
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j)
Re-install the sensor and verify proper operations per Section 2.12.1.1.2 Installation and
Operational Checkout.
Maintenance, 12-24 Month Interval
a)
Replace sensor bearings
Maintenance, 24-36 Month Interval
a)
Recommend complete overhaul of the sensor. This maintenance may be provided by the
factory or done in-house. Section "b)" provides instructions for maintenance of the wind
direction sensor.
b)
Maintenance
The following procedure requires a relatively clean, dry work area, a source of 5V DC
power at approximately 5 mA, and a digital voltmeter. The following sections assume the
sensor has already been removed from the tower and the vane assembly removed. (Refer
to Met One operations manual 021C Wind Direction Sensor, Section 4.1, 4.2, 4.3, 4.4,
Table 4-3, Figure 2-1, and Drawing 2465).
c)
Sensor Bearing Replacement.
1.
Slide the sensor cover (14) down to expose the horizontal potentiometer assembly
(9).
2.
Make sure the two lower special setscrews on the drive coupler (15) next to the
potentiometer are tight. Loosen the two upper special setscrews.
NOTE: Any time the coupler assembly is moved in relation to the shaft, the
alignment must be performed.
3.
Slowly pull the rotating hub shaft assembly (2.7) from the column.
4.
Remove the shield (4) and slinger (5) from the column.
5.
Insert a right-angle type of tool, such as an allen wrench, into the bearing cocking
it slightly to one side and remove the bearing (5). Clean any dirt from the bearing
bores using a cotton swab and alcohol.
6.
Install a new upper bearing in the column assembly. The bearing should slide
easily into the bearing bore. CAUTION: Do not lubricate Bearing. Do not force.
7.
Install the slinger (5) and the shield (4) on the column assembly. If the parts are
damaged or corroded, they should be replaced.
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d)
8.
Insert the rotating hub shaft assembly (2,7) into the column assembly through the
shield (4), slinger (5) and the bearing (6).
9.
Support the drive coupler (15) with one hand and slowly push the rotating hub
shaft (2,7) until the shaft bottoms.
10.
Recalibrate the sensor.
11.
Replace the vane assembly and place back on tower.
Potentiometer replacement (Refer to Met One operations manual 020C Wind Direction
Sensor, Section 4.2, 4.4, 4.6, Table 4-3, Figure 2-1, and Drawing 2465).
1.
Carefully slide the sensor cover (14) down to expose the horizontal potentiometer
assembly (9). Unsolder these wires to the potentiometer (note color code for reinstallation).
2.
Loosen the two lower setscrews closest to the potentiometer in the drive coupler
(15).
3.
Using a pencil, mark the approximate position of the right-hand potentiometer
terminal on the pot support.
4.
Loosen the two setscrews on the potentiometer adapter and remove the
potentiometer.
5.
Install the new potentiometer. Tighten the potentiometer into the adapter using the
two screws. Tighten 3 turns after finger tight.
6.
Re-calibrate the sensor.
7.
Replace the vane assembly and install on the tower.
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Model 020C Wind Direction Sensor Troubleshooting Chart
SYMPTOM
PROBABLE CAUSE
SOLUTION
Loss of supply voltage
Check supply cables
Faulty potentiometer
Replace potentiometer
Bad bearings
Replace bearings
No wind direction output
No change in wind direction
output below 2-5 mph
2.12.1.1.2a
Wind Direction Calibration
Calibration Frequencies
Calibrations are required on the wind direction sensor at site startup and after sensor repairs or
adjustments that will affect the data. Also calibrations will be required after any unacceptable
Q.A. audit. Bi-annual wind direction calibrations are required for the NCore site, annually for the
SLAMS sites. Note: The audit and calibrations should be performed using different equipment
and different personnel.
Wind Direction Calibration Devices
A wind direction calibration device used is a Model 040 wind direction calibrator. The device is
a directional wheel marked from 0.0 degrees to 360 degrees and is mounted on the wind
direction sensor body near the hub. A pointer arm is then attached to the wind direction sensor’s
hub. The pointer is used to read the calibration direction from the directional wheel.
The wind direction starting torque device is a Model 050 Torque Gauge. It consists of a balance
wheel and precision counter weights. The gauge is traceable to NIST MIL-STD-45662A
specifications.
A surveyor’s transit can be used to calibrate the wind direction. It will be used to set the
reference hubs at 180 degrees from the wind direction sensor. The transit sighting scope will be
set to a known direction by using the compass and adjusting for the magnetic declination of the
site.
A wind direction calibration device is a model 042 telescopic sight orientation device. The
telescopic sighting scope is used to align the 191 cross arm locking hub. The wind direction
sensor when mounted into the locking hub will be oriented to 180 degrees. A reference hub of
180 degrees from the wind direction sensor must be established before the scope can be used.
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Calibration Procedure
a) The calibration begins by finding the direction of the wind direction sensor. A transit can
be used approximately 100 feet from the met tower. To avoid possible errors in the
calibration secure the transit tripod firmly in the ground to prevent movement of the
transit when observing the wind vane. Check and double check the transit bubble levels
and horizontal scales for correct adjustments. The transit horizontal direction scales are
set to true North with the compass needle set on magnetic North for the site location. The
magnetic declination for the site can be obtained from a USGS office or the nearest
airport. The transit compass can be read to within 0.5 degrees using a magnifier lens.
With the transit referenced to true North, release the upper direction scale and sight the
wind direction vane in the transit sighting scope cross hairs. The wind vane is taped to fix
the vane’s position once the vane is centered horizontally in the sighting scope’s cross
hairs. The wind direction sensor’s direction value is then read from the data logger and
recorded as found direction. The calibration direction is read from the transit horizontal
direction scale. The reading must be corrected by adding 180 degrees if the scale reading
is less than 180 degrees or subtracting 180 degrees if the scale reading is more than 180
degrees. The correction is done to correct for the reverse shooting of the wind direction
vane from the transit.
b)
To calibrate the direction, a reference hub must be located 180 degrees from the wind
direction sensor. The transit is used to established this point and mark it with a stake.
With the transit set to true north and the wind direction sensor located 180 degrees from
the transit the reference hub point is found. The reference hub stake is set in the vertical
cross hairs of the transit telescopic sight. The wind direction sensor must be in the same
vertical line of the cross hairs. If not the transit is moved in an arc from the sensor until
all the above conditions are satisfied. The reference hub has now been established. If the
reference hub is found disturbed it must be reestablished with the transit before it can be
used for calibrations.
c)
Disconnect the wind direction sensor cable from the sensor. Remove wind vane from the
sensor and then remove the sensor from the cross arm hub. Insert the 042 sighting scope
into the 191 cross arm hub and secure with the locking screw to the hub. The hub
setscrews are loosened so the hub can be rotated. The hub is rotated until the vertical
cross hairs of the sighting scope are in line with the reference hub. The cross arm hub is
then locked with the hub setscrews. Recheck the alignment with the reference hub and
readjust the cross arm hub if needed. When the cross hub is referenced to the reference
hub the scope is removed from the cross arm hub. The wind direction sensor is inserted
into the cross arm hub and set with the sensor setscrew. The wind direction sensor is now
oriented to 180 degrees. The signal cable is connected to the wind direction sensor. The
sensor’s hub and stem alignment marks are then taped together so the sensor direction is
set to 180 degrees. Observe the data logger and record the wind direction reading as the
system calibration.
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d)
The wind direction vane and the signal cable are then disconnected from the wind
direction sensor. The sensor is then removed from the cross arm hub. The Model 040
wind direction calibrator is then set up on the sensor and the signal cable is reconnected.
The wind direction sensor’s hub is rotated until the wind direction response is reading
180 degrees +/- 2.0 degrees on the data logger. The hub position is then taped fixed. The
directional wheel is then set to the pointer to read 180 degrees on the directional wheel.
The wind direction calibrator is now setup to perform the wind direction sensor
calibration. The data logger wind direction value is read and recorded for the calibration
input direction of 180 degrees. The tape is then removed from the hub. The hub can now
be turned using the calibrator pointer to the other calibration points of 270, 360, 10, 90
and 180 degrees located on the directional wheel. All values are read from the data logger
and recorded. After all points are performed the calibrator is removed and the signal
cable disconnected.
e)
Install the 050-torque balance wheel on the wind direction sensor shaft to verify the
starting torque. Screw a stainless steel screw into the 4 cm and the 2 cm position of the
balance wheel. Screw a black nylon screw into the 5 cm position of the balance wheel.
Lay the sensor in a horizontal position and hold the balance wheel level. Release the
balance wheel and watch for a downward deflection caused by the screws. Rotate the
wind direction sensor 90 degrees and level the balance wheel. Release the balance wheel
and watch for the deflection caused by the screws. Repeat the measurements until the
sensor is tested at four evenly spaced points around the sensor’s shaft. If there are no
downward deflections at any test points the counter weight must be increased by 0.5
gm/cm until there is downward movement. Do not exceed 9.0gm/cm counterweight since
starting torque specifications have been exceeded. Record the highest value tested
f)
Reinstall the wind direction sensor to the cross arm mount and reconnect the signal cable.
Install the wind vane to the wind direction sensor. The wind direction calibration is now
complete.
g)
All wind direction calibration values are recorded on the field audit form (see Figure 2,
pg. 23). The system direction calibration performed with the transit or 042 sighting scope
is acceptable if the wind direction response is within +/- 5.0 degrees from the transit’s
direction or +/- 5.0 degrees of the reference hub. The wind direction sensor calibration is
considered acceptable if each wind direction value is within +/- 3.0 degrees from the
calibration input value. The sensor starting torque threshold is acceptable if all measured
points are less than 6.5 grams per centimeter. If any measurements do not meet the
acceptable specifications for a wind speed calibration the sensor must be evaluated by the
technician.
The electronics technician will examine the sensor, make necessary repairs and
recalibrate the sensor. The calibration data and recommendations will be included in an
audit report.
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Figure 2 Wind Direction Cal / Audit Sheet
Wind Direction: Calibration
Site __________
Start Time ____________
Sensor Model ____________
Torque Gauge ____________
Calibration Device ____________
Transit ____________
System Calibration Direction
Audit _____
Date __________
Stop Time ____________
Sensor SN ____________
Device SN ____________
Device SN ____________
Device SN ____________
Degrees
System Value
Degrees
Wind Direction Sensor Calibration
Input Direction
(Deg)
Measured Sensor Torque
Acceptable:
Yes
Data logger Direction
(Deg)
Difference
gms/cm Specifications <6.5 gms/cm
No
Auditor _______________
The system calibration must be within +/- 5.0 degrees of calibration direction for the calibration
to be acceptable (NCore and SLAMS).
Each single point sensor calibration measurements must be within +/- 3.0 degrees of input value
for the calibration to be acceptable.
2.12.1.1.3
R. M. Young Model 05305AQ Wind Speed / Wind Direction
The Model 05305AQ sensor is sensed by a lightweight, carbon fiber thermoplastic (CFT),
helicoid propeller. The wind direction sensor is a lightweight, balanced vane. The instrument
body is UV stabilized plastic with stainless steel and anodized aluminum fittings. The instrument
mounts on a standard 1 inch pipe.
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MODEL 05305AQ Wind Speed/Wind Direction Sensor Specifications
Wind Speed Sensor
Wind Direction Sensor
Range
0 to 50 m/s (112 mph) Range
Sensor
Threshold Sensitivity
30.7 cm air passage
per revolution
2.1 m (6.9 ft) for 63%
recovery
0.4 m/s (0.9 mph)
Output Signal
50 mV per m/s
Distance Constant
Sensor
Delay Distance
Damped Natural
Wavelength
Output Signal
360° mechanical,
355° electrical
Balanced vane
1.2 m (3.9 ft) for
50% recovery
4.9 m (16.1 ft)
13.9 mV per degree
Installation
a) Proper placement of the instrument is very special. Eddies from trees, buildings, or other
structures can greatly influence wind speed and wind direction observations. To get
meaningful data for most applications, locate the instrument well above or upwind from
obstructions.
Grounding the wind monitor is vitally important. Without proper grounding, static
electrical charge can build up during certain atmospheric conditions and discharge
through the transducers.
b) Make the wiring connections to the ESC data logger.
Operational Checkout
Remove the plastic nut on the propeller shaft. Install the propeller on the shaft with the serial
number of the propeller facing forward (into the wind). The vane and propeller should easily
rotate 360° without friction. Check vane balance by holding the instrument base so the vane
surface is horizontal. It should have near neutral torque without any particular tendency to rotate.
A slight imbalance will not degrade performance.
Potentiometer Replacement
The potentiometer has a life expectancy of fifty million revolutions. As it becomes worn, the
element may begin to produce noisy signals or become non-linear. When signal noise or nonlinearity becomes unacceptable, replace the potentiometer.
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2.12.1.1.3a
Wind Speed Calibrations
Wind speed calibration is determined by propeller pitch and the output characteristics of the
transducer. The calibration formula relating propeller rpm to wind speed is shown below.
Standard accuracy is ±0.2 m/s (0.4 mph). For greater accuracy, the sensor must be individually
calibrated in comparison with a wind speed standard.
Wind Speed
m/s
knots
mph
km/h
vs
=
=
=
=
Propeller RPM
0.00512 x rpm
0.00995 x rpm
0.01145 x rpm
0.01843 x rpm
Wind Speed
m/s
knots
mph
km/h
vs
=
=
=
=
0-5 VDC Output
mV x 0.0200
mV x 0.0389
mV x 0.0447
mV x 0.0720
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Calibration Frequencies
Calibrations are required on the wind speed sensor at site startups, sensor repairs or adjustments
that will affect the response or data. Also calibrations are required after any unacceptable QA
audit. Bi-annual wind speed calibrations are required for the NCore site, annually for the
SLAMS sites. The audit and calibrations should be performed using different equipment
and different personnel.
Calibration Procedure see pg. 12, Wind Speed Cal / Audit Sheet see pg. 14
2.12.1.1.3b
Wind Direction Calibrations
Calibration Frequencies
Calibrations are required on the wind direction sensor at site startups, sensor repairs or
adjustments that will affect the response or data. Also calibrations are required after any
unacceptable QA audit. Bi-annual wind direction calibrations are required for the NCore site,
annually for the SLAMS sites. Note: The audit and calibrations should be performed using
different equipment and different personnel.
Wind Direction Calibration Procedure see pg. 20, Wind Direction Cal / Audit Sheet see
pg.23
2.12.1.1.4
Climatronics Model CS800-L Wind Speed / Wind Direction
The Model CS800-L wind speed is sensed by a 3-cup anemometer coupled to a light chopper
that outputs a frequency proportional to wind speed. Wind direction is sensed by a wind vane
coupled to a precision low-torque potentiometer. Both sensors use stainless steel precision ball
bearings for maximum life and low starting thresholds.
MODEL CS800-L Wind Speed/Wind Direction Sensor Specifications
Wind Speed
Wind Direction
Accuracy
0.25 mph or 1.5%
± 3°
Threshold
<1 mph
<1 mph
Distance Constant
8.0 ft of air max
8.0 ft of air max
Damping Ratio
0.4 to 0.6 at 10° displacement
Operating Range
0 – 125 mph
0 - 360° mechanical
Installation
Siting
As a rule of thumb, wind sensors should be located away from obstructions (e.g., trees or
buildings) by a horizontal distance of at least ten times the height of the obstruction. If it is
necessary to mount the sensors on a roof of a building, the height of the sensors above the
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roof should be at least 1.5 times the height of the building.
Maintenance, 1 month
• Visually inspect the cupwheel and vane assemblies for damage
• Do a visual/audio inspection of anemometer at low speeds. Make sure the cupwheel
assembly rotates freely, without any wobble. Worn bearings will often produce an
audible noise.
Maintenance, 3 month
• Measure bearing torque to determine if bearings need replacement (unless bearings are
being replaced on a periodic schedule). For a 1 mph starting threshold, bearing torque
should not exceed 0.28 g-cm for the anemometer, and 6.0 g-cm for the vane.
Maintenance, 12 month
• Replace anemometer bearings
• Check vane linearity
Maintenance, 24 month
• Replace vane bearings
Troubleshooting
Wind Direction
-99999 or random negative numbers displayed in input location
• Make sure the battery voltage is between 9.6 and 16 VDC.
• Verify the sensor is wired to the Single-Ended input channel specified by the manual.
• Make sure parameter 2 of Instruction 4 is 5.
0.0000 or slightly negative numbers displayed in input location
• Make sure the execution interval has been entered in the program table.
• Verify the sensor is wired to the excitation channel specified by parameter 4 of
Instruction 4. Parameter 6 should be 2500 for the CR10, 5000 for the 21X/CR7.
Wind Speed
Unreasonable results displayed in input location
• Inspect the sensor for damage or contamination.
• Check that the multiplier and offset in Instruction 3 are correct for the desired
engineering units.
Offset only displayed in input location
• Make sure the sensor is properly wired to the 5V and G terminals on the CR10, or to
the CAO port and ground on the 21X or CR7 data loggers.
2.12.1.1.4a
Wind Speed Calibrations
Calibrations are required on the wind speed sensor at site startups, sensor repairs or adjustments
that will affect the response or data. Also calibrations are required after any unacceptable QA
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audit. Bi-annual wind speed calibrations are required at all NCore sites, annually for non-NCore
sites. The audit and calibrations should be performed using different equipment and
different personnel.
Wind Speed Calibrations Devices
Accurate wind direction calibration requires a Model 18801 Vane Angle Bench Stand. Begin by
connecting the instrument to a signal conditioning circuit which has some method of indicating a
wind direction value. This may be a display which shows wind direction values in angular
degrees or simply a voltmeter monitoring the output. Orient the base so the junction box faces
due south. Visually align the vane with the crossmarkings and observe the indicator output. If the
vane position and indicator do not agree within 5°, it may be necessary to adjust the
potentiometer coupling inside the main housing.
It is important to note that, while the sensor mechanically rotates through 360°, the full scale
wind direction signal from the signal conditioning occurs at 355°. The signal conditioning
electronics must be adjusted accordingly. For example, in a circuit where 0 to 5.000 VDC
represents 0° to 360°, the output must be adjusted for 4.930 VDC when the instrument is at 355°
(355°/360° x 5.000 volts = 4.930 volts).
Wind Direction
Direction
vs
=
0-5 VDC Output
mV x 0.072
Wind Speed Cal / Audit Sheet see pg. 14
2.12.1.1.4b
Wind Direction Calibrations
Calibration Frequencies
Calibrations are required on the wind direction sensor at site startup and after sensor repairs or
adjustments that will affect the data. Also calibrations will be required after any unacceptable
Q.A. audit. Bi-annual wind direction calibrations are required for the NCore site, annually for the
SLAMS sites. The audit and calibrations should be performed using different equipment
and different personnel.
Wind Direction Calibration Device
A surveyor’s transit can be used to calibrate the wind direction. It will be used to set the
reference hubs at 180 degrees from the wind direction sensor. The transit sighting scope will be
set to a known direction by using the compass and adjusting for the magnetic declination of the
site.
A wind direction calibration device used is a Climatronics linearity direction wheel disk
(101965). The linearity test fixture consists of a stand, a notched calibrated dial, and one Allen
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key, and a four foot length of cable. The stand has a connector and roll pin at the base, and a
spring index pointer at the top. A length of cable with a connector at the end is wired into the
base connector. To align the transmitter and check linearity at the site, proceed as follows:
(NOTE: This procedure assumes a NORTH-SOUTH orientation of crossarm, with the wind
direction sensor at the SOUTH end).
1) Visually align the vane shaft along the crossarm with the vane tail pointing toward the wind
speed sensor. A reading corresponding to approximately “SOUTH” should be obtained. If
not, check out the electronics and orientation of the crossarm before proceeding to Step 2.
2) Remove the wind direction sensor. Using the Allen key supplied, loosen the two set screws
in the vane hub, and remove the vane from the shaft.
3) Take the connector at the end of the cable, and plug it into the crossarm where the sensor
was. Plug the sensor into the fixture base making sure the slot in the sensor is aligned with
the pin in the fixture.
4) Place the notched dial over the shaft so the index end of the pointer is in the 180° notch.
Rotate the sensor cap until the dial hub fits on the stepped portion. The output reading should
correspond to SOUTH.
5) If the reading obtained in Step 4 is correct, go to Step 6. If not, proceed as follows:
a) Using the Allen key, loosen the two set crews in the sensor hub.
b) With the index pointer still in the 180° notch, rotate the shaft until an output reading
corresponds to SOUTH is obtained. Retighten the screws.
6) Move the pointer out of the 180° notch and rotate dial to the next notch, allowing the pointer
to detent into the notch. Check the corresponding output reading. Continue above for the full
360° rotation, thus checking the linearity.
NOTE: dial is calibrated so that 90=EAST, 0=NORTH, and 270=WEST.
.
Wind Direction Cal / Audit Sheet see pg.23
2.12.1.1.5
Campbell Model HC2S3 Relative Humidity
The Model HC2S3 is a rugged, accurate temperature/RH probe that is ideal for long term,
unattended applications. The probe uses a Rotronic’s IN1 capacitive sensor to measure RH and a
100 ohm PRT to measure temperature. For optimum results, the HC2S3 should be recalibrated
annually.
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Model HC2S3 Specifications
Relative Humidity Sensor
Relative Humidity
0 to 100% nonMeasurement Range condensing
RH Output Signal
0 to 1 VDC
Range
Accuracy @ 20°C
±0.8% RH per year
Long Term Stability <1% RH/year
Installation
Sensors should be located over an open level area at least 9 m (EPA) in diameter. The surface
should be covered by short grass, or where grass does not grow, the natural earth surface.
Sensors should be located at a distance of at least four times the height of any nearby obstruction,
and at least 30 m (EPA) from large paved areas. Sensors should be housed in a suitable radiation
shield.
Standard measurement heights:
1.5 m (AASC)
1.25 to 2.0 m (WMO)
2.0 m (EPA)
Sensor Maintenance
Corroded, discolored or clogged filters should be replaced. To replace the filter, unscrew the
filter from the probe and pull it straight away, being careful not to bend or damage the sensors.
Before putting on the replacement filter check the alignment of the sensors with the probe, and if
necessary, carefully correct the alignment before installing the filter.
The Teflon filter tip is recommended when the sensor is installed in close proximity to the ocean
or other bodies of salt water. A coating of salt (mostly NaCl) may build up on the radiation
shield, sensor, filter and even the sensors. A buildup of salt on the filter or sensors will delay or
destroy the response to atmospheric humidity.
Long term exposure of the relative humidity sensor to certain chemicals and gases may affect the
characteristics of the sensor and shorten its life. The resistance of the sensor depends strongly on
the temperature and humidity conditions and the length of the pollutant influence. In general, the
HC2S3 requires minimal maintenance. The radiation shield should be kept clean and free of
debris, and the sensor should be calibrated annually.
In general, the HC2S3 requires minimal maintenance. The radiation shield should be kept clean
and free of debris, and the sensor should be calibrated annually.
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Troubleshooting
Symptom: -9999, NAN, -40°C, or 0 % relative humidity
1. Check that the sensor is wired to the correct analog input channels as specified by the
measurement instructions.
2. Verify the voltage range code for the single-ended or differential measurement instruction is
correct for the data logger type.
3. Verify the green power wire is connected to the 12V, SW12V, or 5V terminal. Cables longer
than 3 m (10 ft) should be powered by the 12V, rather than the 5V terminal.
A voltmeter can be used to check the output voltage for temperature and relative humidity on the
brown and white wires respectively (temperature °C = mV * 0.1 – 40.0; relative humidity % =
mV * 0).
Symptom: Incorrect temperature or relative humidity
1. Verify the multiplier and offset parameters are correct for the desired units and temperature
range.
2. Default settings are listed in Appendix A of the manual, which include the setting “Limit
humidity output to 100%”. This setting is “disabled” for probes purchased through Campbell
Scientific. For example, at -20°C the accuracy is ±2.3%, so a reading of 102.3% at 100%
humidity is within the accuracy specification. Programs created by Short Cut set humidity
values greater than 100% and less than 103% to 100%. Humidity values greater than 103%
are left unchanged to indicate a problem with the probe or measurement.
2.12.1.1.5a
Relative Humidity Calibration
After saving calibration points to the memory of a probe or device, the HP23 can be used to do a
humidity and temperature adjustment of up to two probes, transmitters or other devices.
Humidity and temperature adjustment are two separate processes.
• Press the MENU key and select either “Probe 1” or “Probe 2”. Press ENTER to activate
the Probe 1 or Probe 2 menu item.
• When the device is a HygroClip 2 probe connected to a HF5 or HF8 transmitter (or
similar device), select “Probe 1” and “Probe Sel” from the menu and press ENTER. Use
the UP or DOWN arrow to select the probe to be calibrated (HF5 transmitter: be sure to
select probe 1)
• Use the DOWN arrow key to select either “Temp Adjust” or “Humi Adjust” (we
recommend selecting Temp Adjust first). The following steps are the same for a
temperature or a humidity adjustment.
• Press ENTER to confirm and open the next sub-menu.
• Optional: with the “Acquired Points” menu item selected press ENTER and review the
calibration points present in memory. This submenu allows you to delete unwanted
calibration points. Press MENU when done.
• Use the DOWN arrow key to select the “Adjust” menu item and press ENTER to
confirm.
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•
Press ENTER to activate the Adjust function. This function automatically erases the
calibration points in memory. When done adjusting, the HP23 automatically exits the
menu.
The calibration method is based on the constant water vapor pressure over a saturated salt
solution and constant temperature. Chemicals used for the calibration are lithium chloride
(LiCl), sodium chloride (NaCl), and potassium sulfate (K2SO4). The salt solutions create a
humidity of approximately 13%, 75%, and the latter approximately 97% at 68ºF (20ºC). All of
these chemicals are available from local suppliers. To guarantee accurate calibration, the salts
must be of high purity. The HP23 Calibrator is used to calibrate the relative humidity probe.
Greenspan’s Calibration Table
°C
0
5
10
15
20
25
30
35
40
45
50
LiCl
11.23±0.54
11.26±0.47
11.29±0.41
11.30±0.35
11.31±0.31
11.30±0.27
11.28±0.24
11.25±0.22
11.21±0.21
11.16±0.21
11.10±0.22
NaCl
75.5±0.3
75.7±0.3
75.7±0.2
75.6±0.2
75.5±0.1
75.3±0.1
75.1±0.1
74.9±0.1
74.7±0.1
74.5±0.2
74.4±0.2
K2SO4
98.8±1.1
98.5±0.9
98.2±0.8
97.9±0.6
97.6±0.5
97.3±0.5
97.0±0.4
96.7±0.4
96.4±0.4
96.1±0.4
95.8±0.5
The numbers on the right in each column indicate the uncertainty of the reference humidity of
the salt in that temperature.
1) Greenspan, L.: journal of Research of the National Bureau of Standards – A physics and
Chemistry Vol. 81A, No. 1 January-February, pp. 89-95
Calibration Frequencies
Calibrations are required on the relative humidity sensor at site startup and after sensor repairs or
adjustments that will affect the data. Also calibrations will be required after any unacceptable
QA audit. Bi-annual relative humidity calibrations are required for the NCore site, annually for
all SLAMS sites. Note: The audit and calibrations should be performed using different solutions
and different personnel.
Relative Humidity Calibration Procedure
Calibration devices (ER-15) are small, airtight chambers that precisely fit ROTRONIC probes.
The lower part of the device consists of a screw-on lid into which the humidity standard is
poured on to an absorbent textile pad. The specified humidity is generated in the calibration
device after a stabilization period. Stabilization takes longer for high humidity values. The probe
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can then be calibrated or adjusted by comparison with the reference value of the humidity
standard.
a)
The calibration of the relative humidity sensors must be done very carefully to avoid
errors that can be introduced in the audit method. The calibrator must be handled carefully to
prevent the solutions from spilling and damage to the sealed case. The calibrator must be kept
near 23 degrees Celsius once the salt solutions are inserted. The calibrator must be allowed to
stabilize to within +/- 1.0 degree C. of the ambient temperature at the site. A difference of 1
degree C can produce errors of 3 to 6 % relative humidity at the high point. The relative
humidity sensor probe must be handled carefully to prevent damage to the exposed sensor
element chip after the probe filter is removed. The exposed sensor element chip can be damaged
or become contaminated by foreign matter.
b)
To set up for the relative humidity calibration ambient temperature must be controlled
ambient calibration temperature of 23 degrees C. Fill the calibration device with the appropriate
lithium chloride solution. Place the calibrator in a position so the relative humidity sensor probe
can be inserted into the calibrator. Read the calibrator thermometer and record the reading. Read
the relative humidity value for the calibrator temperature from the calibration table. Record this
value as the relative humidity calibration input. The sensor probe is then removed from the
lithium chloride solution bottle. Remove the calibrator pad and wipe the calibrator. Install new
pad. Fill the calibration device with the appropriate potassium sulfate solution. Let the probe and
the calibrator stabilize for 30 minutes. Read the calibrator thermometer and record the reading.
Read the relative humidity value for the calibrator temperature from the calibration table found
on the calibrator case. Record this value as the relative humidity calibration input. Read and
record the calibrator value for relative humidity. Repeat the procedure for the sodium chloride
solutions. If any reading is out of calibration specifications, adjustment is required.
If all calibration readings are within calibration specifications, no sensor adjustments are
required. The sensor probe is then removed from the last solution bottle. The sensor probe is then
reinstalled on the sensor probe.
c)
The calibration is now completed. Reinstall the sensor probe to the radiation shield. The
relative humidity calibrator must be stored in a room that meets storage requirements.
Calculations
Calibration Difference = relative humidity reading (conc) - Calibration relative humidity
Relative Humidity Cal / Audit Sheet, see pg. 37
2.12.1.1.6
Met One Model 083C Relative Humidity Sensor
The Model 083E sensor probe represents sensitivity, accuracy, linearity and stability not
encountered with conventional relative humidity sensors. It is extremely well suited for
meteorological, industrial, laboratory and other demanding applications.
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Operation
The Model 083D Relative Humidity Sensor is based upon the capacitance change of a polymer
thin film capacitor. A one-micron thick dielectric polymer layer absorbs water molecules through
a thin metal electrode and causes capacitance change proportional to relative humidity. The thin
polymer layer reacts very fast, and therefore, the response time is very short; less than five
seconds to 90% of the final value of relative humidity.
The sensor responds to the full range from 0-100% relative humidity. Its response is essentially
linear, with small hysteresis, and negligible temperature dependence.
Relative Humidity
RH Sensing Element:
Range:
Temperature Operation Range:
Response Time:
Accuracy:
Temperature Coefficient:
Output:
AutoMet Auto ID:
Thin film polymer capacitor
0 to 100% RH
-50 °C to +50 °C (-58 °F to 122 °F)
10 sec. with 2 m/s aspiration
± 2.0% from 0 to100% RH
Compensated internally
0 to 1 VDC Standard (0 to 5.0 VDC Optional)
Yes (Model 593A Only)
Calibration Frequencies
Calibrations are required on the relative humidity sensor at site startup and after sensor repairs or
adjustments that will affect the data. Also calibrations will be required after any unacceptable
QA audit. Bi-annual relative humidity calibrations are required for the NCore site, annually for
all SLAMS sites. Note: The audit and calibrations should be performed using different solutions
and different personnel.
2.12.1.1.6a
Relative Humidity Calibration
Usually, the errors during humidity calibration are due to temperature differences. A temperature
difference of ±1 °C at +20 °C between the air in the chamber and the sensor causes an error of
±3 %RH at 50 %RH and an error of ±3=6 %RH at 97 %RH. The more the transportation or
process temperatures differ from the temperature at the calibration site, the longer the
stabilization time required. In laboratory use, the calibrator should be stored in that part of the
room where the temperature is most stable. The calibrator must be kept out of direct sunlight and
away from localized heat sources. If the probe/transmitter is checked against several humidity
references, the checking must first be made at the dry end.
Handle the probe as little as possible. Do not hold the salt chamber or other parts of the calibrator
in hand during calibration as they warm up and cause errors in the readings.
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-
Leave the calibrator and the probe at the calibration site for at least 30 minutes before starting
the calibration in order to let the probe temperature stabilize to the room temperature.
-
With lithium chloride it is not necessary to use the thermometer as the humidity reading
changes only very slightly in the temperature range of +25 …+30 °C. However, if you use it
make sure that the sleeve is in the correct position and insert it into the 13.5 mm hole of the
LiCl salt chamber.
-
Take off the grid or filter protecting the sensor. Take care not to damage the sensor.
-
Some 12 mm probes need a adapter fitting to fit into the 13.5 mm hole. Adapter fitting
prevents sensor from soaking in the salt liquid. In case an adapter is needed, take off the grid
or filter and replace it with the adapter fitting.
-
Insert the probe into a suitable hole of the LiCl salt chamber. Press it downwards until it
passes the O-rings. The shorter the time the hole stays open before inserting the probe, the
shorter the stabilization time required.
-
Wait until the humidity reading stabilizes; this take about 10 …30 minutes.
-
Read the salt chamber temperature from the thermometer an dread the closest humidity value
from the calibration table (Greenspan’s Calibration table, see pg. 33).
-
Adjust the dry end (DRY, offset) to correspond to the value give in the calibration table.
-
Insert the thermometer into the 13.5 mm hole of the NaCl salt chamber.
-
Insert the probe into a suitable hole of the NaCl (or K2SO4) salt chamber. The shorter the
time the hole stays open before inserting the probe, the shorter the stabilization time required.
-
Wait until the humidity reading stabilizes; this take about 10 …30 minutes. Note: the high
humidity solutions the risk for errors increases. Therefore, the stabilization time should be
longer (approximately 20 …40 minutes).
-
Read the salt chamber temperature from the thermometer an dread the closest humidity value
from the calibration table (Greenspan’s Calibration table, see pg. 33).
-
Adjust the wet end (WET, gain) to correspond to the value given in the calibration table.
Note: separate solutions should be kept for audits / calibrations, and there should be a distinction
from the auditor to the calibrator.
Relative Humidity Cal / Audit Sheet, see pg. 37
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Figure 3 Relative Humidity Cal / Audit Sheet
Relative Humidity: Calibration
Site __________
Start Time ____________
Sensor Model __________
Calibration Device __________
Calibration Input
Relative Humidity
Calibrator
Temperature
(Degrees C)
Audit _____
Date __________
Stop Time ____________
Sensor SN __________
Device SN __________
Input Value
(From Table)
Data logger
Relative Humidity
Readings
Calibration
Difference
Lithium Chloride
Sodium Chloride
Sodium Sulfate
After Adjustments
Lithium Chloride
Sodium Chloride
Sodium Sulfate
Calibration Difference = sensor relative humidity reading - Audit relative humidity
Each calibration point measurement must be with ±7% (NCore) and ±10% (SLAMS) relative
humidity of the calibration input for the calibration to be acceptable.
Acceptable:
Yes
No
Auditor ______________
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2.17.1.1.7
MET One Model 062 Temperature
Met One Instruments’ Temperature Sensors are precision, extended range thermistor devices that
are used for the accurate measurement of ambient air temperature. They are particularly well
suited for field applications, as they exhibit a very high resistance sensitivity. Problems
associated with line lead length, noisy environments, and poor connections are virtually
eliminated. Sensors may be interchanged without requiring system recalibration. Difference
among these sensors are associated with packaging and accuracy, allowing for the precise
solution to sensor selection.
Air temperature measurements are one of the simplest meteorological measurements, but
accurate and representative measurements of air temperature require no less attention to quality
than others. Temperature gradient measurements between two levels above ground on a tower
demand greater accuracy and precision than measurements of temperature alone. Temperature
gradient is commonly known as delta-temperature and is abbreviated ΔT.
High-quality, economical sensors based on electrical resistance that changes with temperature
are readily available and adaptable to many data recording and display systems. The challenge is
to place the sensors in suitable locations and provide proper protection from moisture, wind, and
radiation energy interferences. ASTM International Standard Practice30 for atmospheric
temperature measurements describes the types of shields needed to properly protect electrical
sensors. Naturally ventilated shields can provide adequate protection for many simple air
temperature measurements, but the additional accuracy required for ΔT measurement
necessitates using mechanically aspirated shields to provide uniform airflow across the sensor in
the shield.
Model 062
The Model 062 is a highly accurate version of the Model 060A-2. It is used in pairs for the
measurement of differential temperature (DT), or singly for highly critical ambient temperature
measurement.
Housing:
3/8 in (9.5 mm) OD x 6 in (152.4 mm)
Range:
-50°C to +50°C
Accuracy:
±0.05°C, PSD Compliant
Linearity Deviation: For a system
Max. error per degree
range of:
of differential temperature:
-5°F to +5°F
.02°F
-5°C to +5°C
.02°C
-5°F to +10°F
.02°F
-5°C to +10°C
.02°C
-10°F to +20°F
.02°F
Cable: 1 ft pigtails (for use with 076 or 077 Radiation Shield)
Max. error
over range:
.05°F
.05°C
.1°F
.1°C
.2°F
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Additional length may be supplied, specify length
Installation and Wiring
Temperature sensors should be mounted over a plot of open level ground at least 9 m in
diameter. The ground surface should be covered with non-irrigated or un-watered short grass or,
in areas where grass does not grow, natural earth. Gravel surfaces are also acceptable. The
surface must not be concrete or asphalt or oil-soaked. The standard height for climatological
purposes is 1.25 m to 2 m, but different heights may frequently be required in air quality studies.
For general purposes, the primary temperature sensor is mounted 2 m above ground level, with
the inlet facing away, and at a distance of approximately 1.5 times the tower diameter, from the
tower.
The sensors should not be closer to obstructions, such as trees and buildings, than a distance
equal to four times their height. They should be at least 30 m from large paved areas and not
close to steep slopes, ridges, or hollows. Areas of standing water should also be avoided.
Louvered instrument shelters should be oriented so that the door opens toward true north in the
northern hemisphere. Motor-aspirated shields should also be oriented with the sensors toward
true north in the northern hemisphere.
2.12.1.1.7a
Temperature Calibration
Calibrating a temperature measurement system consists of comparing the output of the device
being calibrated to a known value, and determining if the difference is within acceptable
tolerance limits. Most modern temperature measuring systems do not need adjusting to match
known values if all components are working properly, so acceptance is pass or fail. Improper
signal cable connections or signal processing instructions are more likely sources of problems
producing unacceptable results than the sensors themselves. Additional information about
standardized testing for resistance temperature measuring devices is available from ASTM
International.
Following manufacturer’s instructions and using the on-site signal processing method ensures
that the calibration is representative of the device’s response. Note that some temperature probes
may not be submersible. If this is the case, then follow the manufacturer’s calibration
procedures. A step by step description of a water-submersible temperature sensor follows.
1. The calibration test should be performed at three or more temperature levels spaced across the
range of the sensor, such as 0 degrees C, 20 degrees C and 40 degrees C.
2. Prepare three test baths as stated in step 1.
3. Remove the sensor from the shield.
4. Place the probe and a NIST traceable temperature device in the water bath with the lowest
point, a thermal mass in an ice slurry mixture.
5. To reduce physical stress on the sensors, the probes should be allowed to reach equilibrium
with room conditions when they are removed from one thermal mass and before subjecting
them to another thermal mass.
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6. Record the temperature of the bath from the NIST traceable temperature device and the
reading from the station temperature probe.
7. Remove the NIST traceable temperature device and station temperature probe and place them
in the 20 degree C water bath. Repeat steps 6 and 7.
8. Remove the NIST traceable temperature device and station temperature probe and place them
in the 40 degree C water bath. Repeat steps 6 and 7.
Auditing
The performance audit should consist of challenging the temperature and ΔT sensors to three test
environments at 0 degrees C, ambient temperature, and 40 degrees C using a water bath
compared to a NIST-traceable temperature standard. The temperature, ΔT, and NIST-traceable
temperature probes are simultaneously placed in a water bath until equilibrium is reached for
each desired temperature range. The temperature sensor’s response is compared to the audit
transfer standard response for each test atmosphere, and the ΔT response is recorded at the same
time. The recommended tolerance for an audit is the same as that for a calibration: ±0.5 degrees C for
temperature and ±0.1 degrees C for ΔT.
Ambient Temperature Cal / Audit Sheet, see pg. 45
2.12.1.1.8
Campbell Model HC2S3 Temperature
The Model HC2S3 is a rugged, accurate temperature probe that is ideal for long term, unattended
applications. The probe uses a Rotronic’s IN1 capacitive sensor to measure RH and a 100 ohm
PRT to measure temperature. For optimum results, the HC2S3 should be recalibrated annually.
Model HC2S3 Specifications
Temperature Sensor
Temperature
-50°C to
measurement Range
+100°C
Temperature Output
0 to 1.0 V
Signal Range
Accuracy @ 23°C
±0.1°C
Long Term Stability
<0.1°C/year
Installation
Sensors should be located over an open level area at least 9 m (EPA) in diameter. The surface
should be covered by short grass, or where grass does not grow, the natural earth surface.
Sensors should be located at a distance of at least four times the height of any nearby obstruction,
and at least 30 m (EPA) from large paved areas. Sensors should be housed in a suitable radiation
shield.
Standard measurement heights:
1.5 m (AASC)
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1.25 to 2.0 m (WMO)
2.0 m (EPA)
Sensor Maintenance
Corroded, discolored or clogged filters should be replaced. To replace the filter, unscrew the
filter from the probe and pull it straight away, being careful not to bend or damage the sensors.
Before putting on the replacement filter check the alignment of the sensors with the probe, and if
necessary, carefully correct the alignment before installing the filter.
The Teflon filter tip is recommended when the sensor is installed in close proximity to the ocean
or other bodies of salt water. A coating of salt (mostly NaCl) may build up on the radiation
shield, sensor, filter and even the sensors. A buildup of salt on the filter or sensors will delay or
destroy the response to atmospheric humidity.
The resistance of the sensor depends strongly on the temperature and humidity conditions and
the length of the pollutant influence. In general, the HC2S3 requires minimal maintenance. The
radiation shield should be kept clean and free of debris, and the sensor should be calibrated
annually.
In general, the HC2S3 requires minimal maintenance. The radiation shield should be kept clean
and free of debris, and the sensor should be calibrated annually.
Troubleshooting
Symptom: -9999, NAN, -40°C, or 0 % relative humidity
1. Check that the sensor is wired to the correct analog input channels as specified by the
measurement instructions.
2. Verify the voltage range code for the single-ended or differential measurement instruction is
correct for the data logger type.
3. Verify the green power wire is connected to the 12V, SW12V, or 5V terminal. Cables longer
than 3 m (10 ft) should be powered by the 12V, rather than the 5V terminal.
A voltmeter can be used to check the output voltage for temperature and relative humidity on the
brown and white wires respectively (temperature °C = mV * 0.1 – 40.0; relative humidity % =
mV * 0
Symptom: Incorrect temperature or relative humidity
1. Verify the multiplier and offset parameters are correct for the desired units and temperature
range.
2. Default settings are listed in Appendix A of the manual, which include the setting “Limit
humidity output to 100%”. This setting is “disabled” for probes purchased through Campbell
Scientific. For example, at -20°C the accuracy is ±2.3%, so a reading of 102.3% at 100%
humidity is within the accuracy specification. Programs created by Short Cut set humidity
values greater than 100% and less than 103% to 100%. Humidity values greater than 103%
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are left unchanged to indicate a problem with the probe or measurement.
2.12.1.1.8a
Temperature Calibration
After saving calibration points to the memory of a probe or device, the HP23 can be used to do a
humidity and temperature adjustment of up to two probes, transmitters or other devices.
Humidity and temperature adjustment are two separate processes.
• Press the MENU key and select either “Probe 1” or “Probe 2”. Press ENTER to activate the
Probe 1 or Probe 2 menu item.
• When the device is a HygroClip 2 probe connected to a HF5 or HF8 transmitter (or similar
device), select “Probe 1” and “Probe Sel” from the menu and press ENTER. Use the UP or
DOWN arrow to select the probe to be calibrated (HF5 transmitter: be sure to select probe 1)
• Use the DOWN arrow key to select either “Temp Adjust” or “Humi Adjust” (we
recommend selecting Temp Adjust first). The following steps are the same for a temperature
or a humidity adjustment.
• Press ENTER to confirm and open the next sub-menu.
• Optional: with the “Acquired Points” menu item selected press ENTER and review the
calibration points present in memory. This submenu allows you to delete unwanted
calibration points. Press MENU when done.
• Use the DOWN arrow key to select the “Adjust” menu item and press ENTER to confirm.
• Press ENTER to activate the Adjust function. This function automatically erases the
calibration points in memory. When done adjusting, the HP23 automatically exits the menu.
Maintenance, Annually
a)
Inspect the aspirated radiation shield screen over the intake baffle to remove insects and
any other objects that can interfere with the operation of the motor. The screen can be
cleaned with a brush and soap and water.
b)
Remove the fan assembly by removing the screws attaching it to the blower mount.
Brush or blow off any accumulation of dust. Replace housing and return to service.
WARNING: Ensure the power is off before servicing. Failure to do so will result in exposure to
severe electrical shock.
c)
The motor bearings are permanently lubricated and do not require normal maintenance.
Bearing lubrication should be performed only by personnel familiar with motor
maintenance. Lubrication is not recommended as a standard preventive maintenance
measure.
Operational Checkout
a)
To verify correct wiring and as a rough test of the sensor operation, blowing on the
sensor will cause the relative humidity to increase.
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b)
The relative humidity sensor has been calibrated at the factory and will not change unless
the sensor is damaged. To check for proper operation the output values can be compared
against a local weather station. Exact correlation is not to be expected due to atmospheric
and geographical variations.
Maintenance, 6-12 months
The instrument should operate for extended period of time with minimum amount of care and
maintenance. (Rotronic HygroPalm HP23-A Hand-Held Indicator User Guide).
a)
Replace battery
b)
Both the Pt 100 RTD temperature sensor used in the probe and associated electronics are
very stable and should not require any calibration after the initial factory adjustment.
Long term stability of the ROTRONIC Hygromer humidity sensor is typically better than
1 %RH per year. For maximum accuracy, calibration of the probe should be verified
every 6 to 12 months. Applications where the probe is exposed to significant pollution
may require more frequent verifications.
c)
Clean or replace the probe dust filter.
Replacement of the Sensor Element
a)
b)
Disconnect the power and unscrew the filter.
Un-solder the old chip and solder a new one in its place.
CAUTION: The sensor chip is very delicate. Do not touch the chip with bare hands. Handle the
chip only by gripping its lead with pliers. When soldering, hold the lead with the pliers to
prevent the heat from soldering operation from damaging the chip. Do not bump the chip when
reinstalling the protective grid.
c)
After replacement of the sensor element, calibrate the sensor.
Ambient Temperature Cal / Audit Sheet, see pg. 44
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Figure 4 Ambient / Delta Temperature Cal / Audit Sheet
Ambient Temperature and Delta Temperature: Calibration
Site __________
Start Time ____________
Sensor Model 2 meters __________
Sensor Model 10 Meters __________
Calibration Device __________
Audit _____
Date __________
Stop Time ____________
Sensor SN __________
Sensor SN __________
Device SN __________
Differential baths
negative delta
temperature
Differential baths
positive delta
temperature
na
na
2 meter difference temperature
(degrees C)
na
na
RTD sensor temperature
(degrees C)
na
na
na
na
Input Tests Points >
0ºC
(32 ºF)
20ºC
(68 ºF)
40ºC
(104 ºF)
RTD sensor temperature
(degrees C)
2 meter level data logger
temperature (degrees C)
10 meter level temperature data
logger (degrees C)
10 meter difference
temperature (degrees C)
Delta temperature data logger
(degrees C)
Sensors delta difference
10 meter - 2 meter
Delta Temperature difference
(Delta temp- sensors
difference)
Specification Temperature Verification Test Accuracy = ±0.5 ºC (NCore) ±1.0 ºC (SLAMS)
between RTD and sensors.
Acceptable:
Yes
No
Auditor _________
National Core (NCore) and State and Local Air Monitoring Station (SLAMS)
Meteorological Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
July 1, 2015
Page 45 of 52
2.12.1.1.9
SU-100 UV Solar Radiation Sensor
Ultraviolet (UV) radiation constitutes a portion of the electromagnetic spectrum from 100
to 400 nm, and is further subdivided into three wavelength ranges: UV-A (315- 400nm),
UV-B (280-315nm), and UV-C (100-280 nm). Much of the UV-B and all of the UV-C
wavelengths from the sun are absorbed by the Earth’s atmosphere. There are also many
artificial UV light sources available that a select wavelength range or offer a broadband
UV radiation source.
Most UV sensors designed for sunlight measurements are sensitive to UV radiation in the
UV-A and UV-A ranges. The SU-100 UV sensors detect UV radiation from 250 to 400
nm and are calibrated in photon flux units of micromoles per square meter per second
(µmol m2s1). The output can also be expressed in energy flux units of watts per square
meter (W m2, equal to Joules per second per square meter).
Typical applications of UV sensors include incoming UV radiation measurement in
outdoor environments.
Specifications
Sensitivity: 0.20 mV per µmol m2s1
0.61 mV per W m2
Calibration Factor: 5.0 µmol m2s1 per mV (reciprocal of sensitivity)
1.65 W m2 per mV (reciprocal of sensitivity)
Calibration Uncertainty: 10%
Measurement Repeatability: <1%
Non-linearity: < 1% (up to 300 µmol m2s1)
Response Time: < 1 ms
Field of View: 180°
Operating Environment: -40 to 70°C
0 to 100% relative humidity
Calibration Traceability:
Apogee SU-100 UV sensors are calibrated through side-by-side comparison to the mean
of four Apogee model SU-100 transfer standard UV sensors under high intensity
discharge metal halide lamps. The transfer standard UV sensors are calibrated through
side-by-side comparison to an Apogee model PS-200 spectroradiometer under sunlight
(clear sky conditions).
National Core (NCore) and State and Local Air Monitoring Station (SLAMS)
Meteorological Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
July 1, 2015
Page 46 of 52
Installation
Mount the sensor to a solid surface with the nylon mounting screw provided. To
accurately measure UV radiation incident on a horizontal surface, the sensor must be
level. An Apogee Instruments model AL-100 leveling plate is recommended for this
purpose. To facilitate mounting on a cross arm, an Apogee Instruments model AM-110
mounting bracket is recommended.
Note: to minimize azimuth error, the sensor should be mounted with the cable
pointing true north in the northern hemisphere. Azimuth error is typically less than 1%,
but it is easy to minimize by proper cable orientation.
In addition to orienting the cable to point toward the nearest pole, the sensor should be
mounted such that obstructions (e.g., weather station tripod/tower or other
instrumentation) do not shade the sensor. Once mounted, the green cap should be
removed from the sensor. The green cap can be used as a protective covering for the
sensor when it is not in use.
Make the wiring connections to the ESC data logger.
Spectral Errors for UV Radiation Measurements with Apogee SU-100 Sensors
Maintenance
Moisture or debris on the sensor is a common cause of low readings. The sensor has a
domed-shaped housing for improved self-cleaning from rainfall, but materials can
accumulate on the photo-sensitive area (e.g., dust during periods of low rainfall, salt
deposits from evaporation of sea spray or sprinkler irrigation water) and partially block
National Core (NCore) and State and Local Air Monitoring Station (SLAMS)
Meteorological Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
July 1, 2015
Page 47 of 52
the optical path. Dust or organic deposits are best removed using water, or window
cleaner and a soft cloth or cotton swab. Salt deposits should be removed with a soft cloth
or cotton swab. Never use an abrasive material or cleaner on the sensor.
2.12.1.1.9a
Solar Radiation Calibration
Calibration Frequencies
The solar radiation sensor has been calibrated at the factory. It will not change unless
damaged. Verifications are required on the solar radiation sensor at site startups, sensor
repairs or adjustments that will affect the response or data. Also calibrations are required
after any unacceptable QA audit or when there is a greater than 10% difference in the
readings (audit device / sensor). The solar radiation sensors will be recertified every three
years.
Audit Devices
The install device will be different than the audit device. Audit results of the sensor
will be recorded with the annual ozone audit. The audit / installation devices will be recertified annually. A logbook will be generated to document the device events (e.g., recertification, maintenance).
2.12.1.2
Data Logger Channel Procedure
Data logger time and date:
• Select the AvTrend icon, enter the username followed by the password, hit "OK"
• Select: "Utilities"
• Select: "Link to Logger"
• From the drop down menu locate the site to run the calibration on
• Select: "Connect"
• Select: "L" to log onto the site data logger (use site password)
• Select: "C", Configuration menu, <ENTER>
• Select: "S", Configure System Parameters, <ENTER>
• Highlight "Logger Time", <ENTER>
• Type in correct time in the format of: HH:MM:SS
Disable Channel on Data Logger
• Press {ESC}{ESC} to return to Home Menu
• Select: "C", configuration menu, <ENTER>
• Select: "D", configure data channels, <ENTER>
• Select: "M", mark channels down / off, <ENTER>
• Select: "RH", <ENTER>
National Core (NCore) and State and Local Air Monitoring Station (SLAMS)
Meteorological Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
July 1, 2015
Page 48 of 52
Setting computer and PDL time/date.
The times for the PDL and computer must be EASTERN STANDARD TIME
Sources for getting the correct time:
1. Call the ECB and ask for the NIST time.
2. Call the NIST Colorado time @ (303) 499-7111 (long distance).
3. Correct time loaded into cell phone.
4. Correct time website, http://tycho.usno.navy.mil/
Check the computer time and date at the lower right hand corner of the computer screen.
If the time and date are not correct; click "START" button, control panel, date/time or
right click computer time on taskbar, select "Adjust Date/Time", type in changes and
select "OK ".
Up the PDL channel: Go to the Home Menu (by pressing {ESC} several times if
needed), Press "L" and <ENTER> the code when it asks for the password and press
<ENTER>.
•
•
•
•
•
•
{ESC} {ESC} {ESC} to Home Menu on PDL
Select: "C", Configuration Menu, <ENTER>
Select: "D", Configure Data Channels, <ENTER>
Select: "E", "Enable/Mark Channel Online", <ENTER>
Use arrow key to select parameter, <ENTER>
Highlight "RH" then press, <ENTER>
The following sequence is used to logout of the data logger:
• Press {ESC}{ESC} to return to Home Menu
• Use arrow ↓ key to select "O" or hit "O" key to logout
Turn off computer screen and DO NOT turn off the computer.
2.12.1.3
Site Visits
Whenever the ECB technicians visit a site, they will:
1.
2.
3.
4.
Document the date, time and reason for the visit in the site logbook.
Check that the site building temperature is between 20º C and 30º C.
Check that the building is secure. Vandalism is reported to the ECB Supervisor.
Check that all monitoring systems are operating within normal ranges (unless the
reason for the visit is site start-up).
5. Down any channels for equipment being repaired, replaced, or audited during the
repair, replacement, or audit.
6. Up any channels after equipment is repaired, replaced, or audited.
National Core (NCore) and State and Local Air Monitoring Station (SLAMS)
Meteorological Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
July 1, 2015
Page 49 of 52
2.12.1.4
Accuracy Audits
The frequency for performing meteorology accuracy audits will be according to:
1. National Core (NCore) Meteorological Calibration and Accuracy Table (see Table 2,
pg. 52).
2. State and Local Ambient Monitoring (SLAMS) Meteorological Calibration and
Accuracy Table (see Table 3, pg. 53).
a)
Meteorology System Audit
The meteorology system audit is performed to insure the meteorological
instrumentation is being operated to QA specifications. The audit provides
information about sensor calibration status, sensor malfunctions, repairs that may
be needed and improvements to the QA plan. The audit is a valuable tool in
determining the data quality of the different meteorological parameters that are
measured. The audit information is recorded on the field audit forms and the
equipment logbook. The date, start and stop times time are logged so the database
will not include values associated with the audit.
When the audit values are more than the parameter(s) criteria, call the ECB
Supervisor and inform the Chief of the situation and print out a copy of the last
autocalibration. The ECB Supervisor will investigate suspicious audits to
determine if there is a problem and if so, where the problem is and how to solve
the problem.
If the problem is with the ECB equipment, the ECB generally fixes the audit
equipment and repeats the audit. If the problem is with the site equipment, the
ECB takes appropriate action to either repair or replace the site equipment. If the
problem is a major site operation problem, the ECB supervisor informs the
Projects and Procedures Supervisor.
b)
Interagency Testing
No interagency testing devices are known to be available from EPA. When such
devices become available NCDAQ will participate in interagency testing.
2.12.1.5 Data Acquisition
a)
When the data logger has been shown to be polling acceptable data, the data will
be automatically collected by the Statistician’s computer using polling routines.
The actions required by the regions are to report reasons for missing data:
identify invalid data and identify data to be changed by the Statistician. The
actions are to be recorded on the problem log sheet meteorological site forms for
documentation purposes.
Data Editing
a) All periods of missing or invalid data must be accounted for. Documentation
National Core (NCore) and State and Local Air Monitoring Station (SLAMS)
Meteorological Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
July 1, 2015
Page 50 of 52
identifying the reasons for missing or invalid data is the meteorology system
checkout list.
b)
Any valid data identified by the data logger as "invalid" data (by flags) must be
verified with proper documentation stating why data is valid. This documentation
should state actions required correcting the problem and why data flags were set
by the data logger.
c)
The data must be exported into a spreadsheet or a database program on the PC.
The data is exported with a start date and end date for the file. The data files are
created monthly for each site. Monthly data files can be edited using the data base
software. The edited data must have documentation to support any editing
changes made to the database.
d)
The database is edited first to satisfy the documentation generated from site
operations or any questionable data. Once all editing is done the database is
screened. The screening process involves comparing the data to expected values
or range of values. The screening is performed manually or by macros using a
PC. All data that does not pass the screening criteria must be examined to
determine if the data is acceptable. The data that is determined unacceptable can
be deleted from the database or marked questionable. A documentation record
must be created to log deleted data and questionable data. This record provides
information about gaps in the data base and quality of the database.
e)
The data now can be transferred to AQS according to procedures. Notify the
Statistician to update when the screening file is ready.
f)
Review the quarterly data reports from AQS, make changes as needed. When
data in AQS is complete and correct, prepare the quarterly data submittal letter for
the signature of the Ambient Monitoring Chief.
2.12.1.6
•
•
•
•
•
•
•
•
MET Parameter Shutdown Procedure
Select the AvTrend icon; enter the username followed by the password, hit "OK"
Select: "Utilities"
Select: "Link to Logger"
From the drop down menu locate the site to shut down
Select: "Connect", when the site has connected
Select: "L", to log onto the site data logger (use site password).
Down the associated parameter (WS, WD, RH, etc)
Submit the site shutdown form.
National Core (NCore) and State and Local Air Monitoring Station (SLAMS)
Meteorological Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
July 1, 2015
Page 51 of 52
Table 1 Database Screening Criteria
Wind Speed
Wind speed less than 0 m/sec or greater than 25 m/sec, does not
vary more than 0.1 m/sec for 3 consecutive hours
Wind Direction
Wind direction less than 0 degrees or more than 360 degrees, does
not vary more than 1 degree for 3 consecutive hours
Temperature
Does not vary more than 0.5 degrees C for 12 consecutive hours,
more than 5.0 degrees C change from previous hour
Relative Humidity
Does not vary more than ±7% RH
Table 2 NCore Meteorological Calibration and Accuracy Criteria
Verification/Calibration
Measurement
Type
Ambient
Temperature
3 pt. Water Bath
with NIST
traceable
thermistor or
thermometer
NIST-traceable
Psychrometer or
standards
solution
NIST-traceable
Synchronous
Motor, CTS
method
Solar Noon,
GPS Magnetic
Compass, CTS
method
Relative
Humidity
Wind Speed
Wind
Direction
Acceptance
Criteria
±0.5 ºC
Accuracy
Frequency
SemiAnnually
±7% RH
SemiAnnually
±0.25m/s ≤5m/s;
5%>2m/s not to
exceed 2.5m/s
SemiAnnually
±5 degrees;
includes
orientation error
SemiAnnually
Type
Acceptance
Criteria
±0.5 ºC
Frequency
3 pt. Water Bath
with NIST
traceable
thermistor or
thermometer
NIST-traceable
Psychrometer or
standards
solution
NIST-traceable
Synchronous
Motor
Annually
±7% RH
Annually
±0.25m/s ≤5m/s;
5%>2m/s not to
exceed 2.5m/s
Annually
Solar Noon, GPS
or Magnetic
Compass
±5 degrees;
Includes
orientation error
Annually
This method is described in detail in Section 2.72 – 2.74 of the Quality Assurance Handbook for
Air Pollution Measurement Systems Vol. IV: Meteorological Measurements Version 2.0 (Final).
National Core (NCore) and State and Local Air Monitoring Station (SLAMS)
Meteorological Monitoring QA Plan
Section 2.12.1
Revision No. 1.5
July 1, 2015
Page 52 of 52
Table 3 State and Local Air Monitoring Station (SLAMS) Meteorological Calibration and
Accuracy Criteria
Verification/Calibration
Measurement
Type
Ambient
Temperature
3 pt. Water Bath
with NIST
traceable
thermistor or
thermometer
NIST-traceable
Psychrometer or
standards
solution
NIST-traceable
Synchronous
Motor, CTS
method
Solar Noon,
GPS Magnetic
Compass, CTS
method
Relative
Humidity
Wind Speed
Wind
Direction
Accuracy
Acceptance
Criteria
±1.0 ºC
Annually
±10% RH
Annually
±0.25m/s ≤5m/s;
5%>2m/s not to
exceed 2.5m/s
Annually
±5 degrees;
includes
orientation error
Annually
Frequency
Type
Acceptance
Criteria
±1.0 ºC
Frequency
3 pt. Water Bath
with NIST
traceable
thermistor or
thermometer
NIST-traceable
Psychrometer or
standards
solution
NIST-traceable
Synchronous
Motor
Annually
±10% RH
Annually
±0.25m/s ≤5m/s;
5%>2m/s not to
exceed 2.5m/s
Annually
Solar Noon, GPS
or Magnetic
Compass
±5 degrees;
Includes
orientation error
Annually
This method is described in detail in Section 2.72 – 2.74 of the Quality Assurance Handbook for
Air Pollution Measurement Systems Vol. IV: Meteorological Measurements Version 2.0 (Final).
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