Delta OHM LP PHOT 02 User manual

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Our instruments' quality level is the results of the product continuous
development. This can bring about differences between the information written
in this manual and the instrument that you have purchased. We cannot entirely
exclude errors in the manual, for which we apologize.
The data, figures and descriptions contained in this manual cannot be legally
asserted. We reserve the right to make changes and corrections without prior
notice.
REV. 1.0
10 jan. 2007
LP PHOT 02

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LP PHOT 02
1 Introduction
LP PHOT 02 probe measures illuminance (lux), defined as the ratio between the
luminous flux (lumen) passing through a surface and the surface area (m2).
The spectral response curve of a photometric probe is similar to the human eye curve,
known as standard photopic curve V( λ ). The difference in spectral response between
LP PHOT 01 and the standard photopic curve V(λ) is calculated by means of the error
f1'.
LP PHOT 02 has been designed for long-time outdoor measurements. The luxmeter
designed for outdoor readings, is basically used for taking weather and climate
measurements during daylight .
The luxmeter is produced in three versions:
LP PHOT 02 PASSIVE*
LP PHOT 02 AC ACTIVE , 4..20mA CURRENT output
LP PHOT 02 AV ACTIVE , 0..1 or 0..5 or 0..10 V VOLTAGE output,
to be defined at the order.
* Using SICRAM Module VP 472 it is possible to connect passive pyranometer to
Indicator D09847.
2 Working principle
LP PHOT 02 luxmeter is based on a solid state sensor, whose spectral response has
been adapted to the desired one, by means of special filters. The relative spectral
response curve is shown in fig.1.
Fig1
LP PHOT 02 is provided with a 50 mm diameter transparent glass dome, in order to
protect the sensor against atmospheric damage.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
360 460 560 660 760
Lambda (nm)
Relative spectral response
- - - -: standard photopic curve
_
____: spectral response
LP PHOT 02 probe

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The cosine corrected response has been obtained through both the PTFE diffuser and
case particular shapes. Deviation between the theoretical response and the real one, is
shown in fig.2.
Fig.2
The LP PHOT 02 cosine response allows for use even when the sun elevation is low.
3 Installing and mounting the luxmeter for global radiation
measurements:
Before installing the luxmeter, the silica-gel cartridge must be refilled. Silica-gel
crystals absorb humidity in the dome chamber and in case of particular climatic
conditions, prevent internal condensation forming on the dome inner wall, with a
consequent alteration in measurements.
Do not wet or touch the instrument with your hands while refilling the silica-gel
cartridge. Carry out the following instructions in a dry environment:
1- Loosen the three screws that fix the white shade disk
2- Unscrew the silica-gel cartridge using a coin
3- Remove the cartridge perforated cap
4- Open the silica-gel sachet (supplied with the luxmeter)
5- Fill the cartridge with silica-gel crystals
6- Close the cartridge with its own cap, and check that the sealing O-Ring is
in the right position.
7- Screw the cartridge to the luxmeter using a coin
8- Make sure the cartridge is tightly screwed (otherwise silica-gel crystal will
last for a shorter time)
9- Position the shade and tighten it with the screws
10- The luxmeter is ready for use
-2
0
2
4
6
8
10
0 1020304050607080
Angle
% shifting from theoretical response

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Fig.3 shows the operations needed to refill the cartridge with silica-gel crystals
Fig.3
•To allow cleaning the outer dome regularly and carrying out the instrument
maintenance, LP PHOT 02 should be mounted in easily reachable places. At
the same time, you should check that no building, tree, or any other obstacle
exceeds the horizontal plane where the luxmeter is mounted. In case this is not
possible, you should find a place where obstacles do not exceed 5 degrees
elevation over the path followed by the sun from rising until sunset.
•The luxmeter should be located far from any obstacle which might reflect
sunlight (or any shadow) onto the instrument.
•For a correct horizontal placing, LP PHOT 02 is provided with a bubble level;
inclination adjustment of the luxmeter is made by means of two leveling
screws. Use the two 6mm-diameter screw holes with an interaxial distance of
65 mm, to mount the instrument on a plane. To access the holes, remove the
shade disk and reposition it after mounting (see fig. 4).
•LP S1 mounting kit (fig. 5) is supplied upon demand as an accessory, and
allows for an easy mounting of the instrument on a mast. The mast maximum
diameter shall not exceed 50 mm. The operator will check that the mast height
does not exceed the luxmeter plane, in order to avoid measurement errors due
to any reflection or shadow of the mast itself. To fix the luxmeter to the
mounting bracket, remove the shade disk by loosening the three screws, then
fix the luxmeter to the bracket and mount the white shade disk again.
•The luxmeter should be thermally isolated from the mounting bracket, and the
electrical contact with the ground must be properly made.
AB
CD
Silica-gel cartridge
Perforated cap
Filling Closing the cartridge
LP G
LP SG

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HD 2003.83
HD 2003.77C
HD 2003.77
HD 2003.79
HD 2003.85
HD 2003.84
Spirit Level
104 mm
50.0 mm
Foro di Fissaggio
65.0 mm
79.0 mm
D6 mm
165 mm LP PHOT 02 AC
LP PHOT 02 AV
LP PHOT 02
Fixing holes
HD9906.47 HD9906.47.2
HD9906.46
HD9906.46.2
Fig 4
Fig.5
Pyranometer LP PHOT 02
with LP S1
LP S1

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4 Electrical Connections and requirements for electronic
readout devices
LP PHOT 02 is produced in 3 versions, LP PHOT 02, LP PHOT 02 AC and LP PHOT
02 AV.
•LP PHOT 02 luxmeter is passive and it does not require any power supply.
•LP PHOT 02 AC, AV are active and need power supply.
Required voltage is as follows:
8-30 Vcc for LP PHOT 02 AC and LP PHOT 02 AV with 0..1V and 0..5V autput
supply.
14-30 Vcc for LP PHOT 03 AV with 0..10 V output.
•All version are supplied with a 4 pole connector.
•The optional cable is terminated with a connector at one end and it is made of
PTFE UV-proof. It is provided with 3 wires and a braided wire (shield). Cable colors
and connector poles are matched as follow (figure 6):
Fig.6
LP PHOT 02
Connector Function Color
A Shield ( ) Black
B Vout (+) Red
C Vout (-) Blue
D Housing ( ) White
LP PHOT 02 AC
Connector Function Color
A Shield ( ) Black
B Positive (+) Red
C Negative (-) Blue
D Housing ( ) White
LP PHOT 02 AV
Connector Function Color
A Shield ( ) Black
B (+) Vout Red
C (-) Vout e (-)Vcc Blue
D (+) Vcc White

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•The LP PHOT 02 luxmeter has to be connected either to a millivoltmeter or to
a data acquisition system with input resistance > 5MΩ. Typically, the radiometer
output signal does not exceed 150 mV. In order to better exploit the radiometer
features, the readout instrument should have a 1μV resolution.
fig. 7
•LP PHOT 02 AC is to be connected to a DMM and a power supply as show
below (Figure 8).To read the signal, the load resistance must be ≤500Ω
LP PHOT 02 AC
+Vcc
I out
Power Supply
+
+
-
-
DMM
C
B
Fig. 8
•LP PHOT 02 AV is to be connected to a DMM and a power supply as show
below (Figure 9). To read the signal, the load resistance must be ≥100kΩ
LP PHOT 02 AV
+Vout
-Vcc,
- Vout
Power Supply
+
+
-
-
DMM
+ Vcc
C
D
B
Fig. 9
5 Maintenance:
Blue Red
Screeno (Black)

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In order to grant the best precision and accuracy in measurements, the outer dome
must be always kept clean; the cleaner you keep the dome, the better the accuracy in
measurements will be. Washing can be made with water and standard lens paper; in
case this wouldn’t work, use pure ETHIL alcohol. After using alcohol, the dome must
be washed with water only. Sudden rise and fall in temperature throughout day and
night, might cause condensation to appear on the luxmeter dome; in this case the
performed reading is highly overestimated. To reduce condensation, the luxmeter is
provided with a cartridge containing desiccant material, such as Silica-gel. Silica-gel
efficiency decreases in time while absorbing humidity. Active silica-gel crystals are
yellow colored, while they turn into blue when they gradually loose power. To replace
them, see instructions at paragraph n. 3. Silica-gel generally lasts from 2 to 6 months,
depending on which climatic conditions you have and where the luxmeter works.
6 Calibration and measurements:
LP PHOT 02
Luxmeter sensitivity, indicated as S(or calibration factor), allows determining
illuminance by measuring a signal in Volts at the probe ends. Sfactor is measured in
V/klux.
•Once the difference of potential (DDP) has been measured at sensor ends, Ee
illuminance is obtained through the following formula:
Ee= DDP/S
where;
Ee: indicates Illuminance expressed in klux,
DDP: indicates the difference of potential expressed in mV and measured by
the multimeter,
S: indicates the calibration factor expressed in mV/klux and shown on the
luxmeter label (calibration factor is also mentioned in the calibration
report).
LP PHOT 02 AC
The luxmeter sensitivity is set so that:
4..20 mA = 0..150klux
To obtain illuminance the following procedure is to be applied:
-once you know the current ( Iout) absorbed by the instrument and measured with
the DMM, following formula must be applied:
(
)
mAIe out
E4375.9
−
⋅
=
where;
Ee: illuminance in klux,
Iout: current in mA absorbed by the luxmeter

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LP PHOT 02 AV
The pyranometer sensitivity is set so that according to the version:
0..1 V = 0..150 klux
0..5 V = 0..150 klux
0..10 V = 0..150 klux
To obtain irradiance the following procedure is to be applied:
-once you know the instrument output voltage (Vout) measured with the DMM,
following formula must be applied:
oute VE
⋅
=150 for the version 0…1 V
oute VE
⋅
=30 for the version 0…5 V
oute VE
⋅
=15 for the version 0…10 V
where;
Ee: illuminance in klux,
Vout: Output voltage (in Volt) measured by the voltmeter
Each luxmeter is factory calibrated and has its own calibration factor. Calibration is
carried out by using a standard illuminant A, as indicated in CIE publication N° 69
“Methods of characterizing illuminance meters and luminance meters: Performance,
characteristics and specifications, 1987”. Calibration is carried out by comparison with
a reference luxmeter, assigned to Delta Ohm Metrological Laboratory.
To get the best performances from LP PHOT 02, we strongly recommend to check
calibration annually.

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7 Technical specifications:
Typical sensitivity: 1 mV/(klux) LP PHOT 02
4..20 mA (0-150klux) LP PHOT 02AC
0..1,5,10V (0-150klux) LP PHOT 02AV
Response time: <0.5 sec (95%)
Impedance: 0.5 ÷1 KΩ
Measuring range: 0-150 klux
Viewing angle: 2πsr
Spectral range: Standard photopic curve
Operating temperature: -40 °C ÷80 °C
Error f’1<9%
Cosine response/directional error: < 8 % (between 0° and 80°)
Long term instability: <⏐±3⏐%
(1 year)
Non-linearity: <1 %
Temperature response < 0.1%/°C
Dimensions: fig. 4
Weight: 0.90 Kg

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8 Ordering codes
ORDERING CODE ARTICLE
LP PHOT 02 Luxmeter complete with shade disk,
dessicant sachet with silica-gel crystals,
2 silica-gel cartridges, bubble level, 4
pole plug and Calibration Certificate.
LP PHOT 02 AC Luxmeter complete with shade disk,
dessicant sachet with silica-gel crystals,
2 silica-gel cartridges, bubble level, 4
pole plug and Calibration Certificate.
4..20 mA signal Output
LP PHOT 02 AV Luxmeter complete with shade disk,
dessicant sachet with silica-gel crystals, 2
silica-gel cartridges, bubble level, 4 pole
plug and Calibration Certificate. 0..1V,
0..5V, 0..10V signal output (to be define
d
when order)
CP AA 1.5 4 pole plug with UV proof cable,
L=5m.
CP AA 1.10 4 pole plug with UV proof cable,
L=10m.
HD 2003.85 Fixing kit to mount height pyranometer
on φ40mm mast (HD2003.84 +
HD2003.85+HD2003.79)
HD 2003.79 Fixing kit to mount pyranometers on
clamping φ40mm
(HD2003.77+HD2003.79)
HD 2003.77 Clamping for mast φ40mm
LP SP1 UV resistant plastic shade disk (BASF
LURAN S777K)
LP S1 Mounting kit for LP UVA 02: bracket for
attachment to a mast, including fasteners
and leveling screws.
LP SG Desiccant sachet with silica gel crystals,
complete with inner O-ring and cap.
LP G Pack of 5 cartridges of silica gel crystals

CE CONFORMITY
Safety EN61000-4-2, EN61010-1 LEVEL 3
Electrostatic discharge EN61000-4-2 LEVEL 3
Electric fast transients EN61000-4-4 LEVEL 3
Voltage variations EN61000-4-11
Electromagnetic interference susceptibility IEC1000-4-3
Electromagnetic interference emission EN55020 class B
This guarantee must be sent together with the instrument to our service centre.
N.B.: Guarantee is valid only if coupon has been correctly filled in all details.
RENEWALS
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Instrument type LP PHOT 02
Serial number
GARANZIA GUARANTEE
GARANTIE GARANTIA
GUARANTEE CONDITIONS
All DELTA OHM instruments have been subjected to strict tests and are guaranteed for 24 months
from date of purchase. DELTA OHM will repair or replace free of charge any parts which it considers
to be inefficient within the guarantee period. Complete replacement is excluded and no request of
damages are recognized. The guarantee does not include accidental breakages due to transport,
neglect, incorrect use, incorrect connection to voltage different from the contemplated for the
instrument. Furthermore the guarantee is not valid if the instrument has been repaired or tampered
by unauthorized third parties. The instrument has to be sent to the retailer without transport charge.
For all disputes the competent court is the Court of Padua.
RoHS
2002/95/EC