Delta OHM LPS02 Series Photometric Probe User Manual
- June 13, 2024
- Delta OHM
Table of Contents
- INTRODUCTION
- TECHNICAL SPECIFICATIONS
- MEASURING PRINCIPLE
- INSTALLATION
- CONFIGURATION
- ASCII PROPRIETARY PROTOCOL
- MODBUS-RTU PROTOCOL
- MEASUREMENT WITH ANALOG OUTPUT (only LPS02MA…)
- USE OF THE DIAGNOSTIC SENSORS
- MAINTENANCE
- SAFETY INSTRUCTIONS
- ACCESSORIES ORDERING CODES
- DISPOSAL INFORMATION
- References
- Read User Manual Online (PDF format)
- Download This Manual (PDF format)
Operating manual
Pyranometers PYRAsense
LPS02 series
www.deltaohm.com
Keep for future reference.
INTRODUCTION
PYRAsense series pyranometers measure the global irradiance on a flat surface
(W/m 2 ), sum of direct solar irradiance and diffuse irradiance. The PYRAsense
LPS02 series falls within the Spectrally Flat Class B pyranometers according
to the ISO 9060:2018 standard and meets the requirements of the WMO “Guide to
Instruments and Methods of Observation”.
The internal temperature, relative humidity and pressure diagnostic sensors
allow keeping the pyranometer operating conditions under control all the time
and foresee any maintenance intervention in advance, thus ensuring always
reliable measurements.
The integrated bubble level and the adjustable feet facilitate horizontal
positioning during installation. As option, they can be equipped with a tilt
sensor (option T in the ordering code) which, in addition to facilitating the
installation of the pyranometer, allows continuous monitoring of the correct
installation.
The various models are distinguished by the type of output available and by
the presence or absence of the “tilt” sensor:
| Output| Tilt
---|---|---
Model| Digital RS485 Modbus-RTU| Analog
LPS02M00| **| —| —
LPS02M0T| **
LPS02MA0| **| Configurable 4…20 mA (default), 0…20 mA, 0…1 V, 0…5 V or
0…10 V| —
LPS02MAT| **
The irradiance range for the analog output is user configurable (default,
0…2000 W/m 2 ).
The pyranometers are factory calibrated in accordance with the ISO 9847:2023
(Type A1) standard: ”Calibration of pyranometers by comparison to a reference
pyranometer”. The calibration is performed by comparison with the reference
sample calibrated annually at WRC (World Radiation Center).
The DATAsense PC application software, downloadable from the Delta OHM
website, allows configuring the sensor (e.g., Modbus parameters, measuring
range for the analog output, etc.), monitor the measurements in real time,
even graphically for the irradiance, and save the values detected during the
connection in a file.
TECHNICAL SPECIFICATIONS
Sensor | Thermopile |
---|---|
Measuring range | -200…4000 W/m2 |
The irradiance range for the analog output is configurable (default 0…2000
W/m2)
Resolution| 0.1 W/m2
Viewing angle| 2p sr
Spectral range (50%)| 283…2800 nm
Output| RS485 Modbus-RTU (isolated)
Optional additional analog output configurable 4…20 mA (de- fault), 0…20 mA,
0…1 V, 0…5 V or 0…10 V
Power supply| 7…30 Vdc for RS485 output 10…30 Vdc for analog output (except
0…10 V) 15…30 Vdc for 0…10 V output
Consumption LPS10M0x LPS10MAx| 15 mA @ 24 Vdc / 21 mA @ 12 Vdc
37 mA @ 24 Vdc & Iout=22 mA / 43 mA @ 12 Vdc & Iout=22 mA
Connection| 5-pole M12 (LPS02M0x) / 8-pole M12 (LPS02MAx)
Weight| 620 g approx.
Operating conditions| -40…+80 °C / 0…100 %RH / Max. altitude 6000 m
Bubble level accuracy
(See specifications below for Tilt sensor accuracy)| < 0.2°
Protection degree| IP 67
Materials| Housing: anodized aluminium Screen: ASA
Dome: optical glass
MTBF| > 10 years
Dimensions (mm) Technical Specifications According to ISO 9060:2018
Classification | Spectrally Flat Class B |
---|---|
Response time (95%) | < 10 s |
Zero offset
a) response to a 200 W/m2 thermal radiation
b) response to a 5 K/h change in ambient temperature
c) total zero offset including the effects a), b) and other sources| ****
<÷±10÷W/m2
<÷±4÷W/m2
<÷±15÷W/m2
Long-term instability (1 year)| <÷±1÷ %
Non-linearity| <÷±1÷ %
Directional response (up to 80° with 1000 W/m2 beam)| <÷±18÷ W/m2
Spectral error| <÷±0.5÷ %
Temperature response (-10…+40°C)| <÷±1.5÷ %
Tilt response| <÷±1÷ %
Diagnostic sensors
Internal Temperature|
---|---
Measuring range| -40…+80 °C
Resolution| 0.1 °C
Accuracy| ±0.5 °C (0…60 °C)
Internal Relative Humidity|
Measuring range| 0…100%
Resolution| 0.1%
Accuracy| ±3% @ T=25 °C & RH=20…80%
Internal pressure|
Measuring range| 300…1100 hPa
Resolution| 0.1 hPa
Accuracy| ±1 hPa (0…60 °C)
Tilt sensor (only LPS03MxT)
Measuring range | 0…180° |
---|---|
Resolution | 0.1° |
Accuracy | < 0.5° |
MEASURING PRINCIPLE
PYRAsense series pyranometers are based on a thermopile sensor. The thermopile
sensitive surface is coated with a black matt paint, which allows the
pyranometer not to be selective at different wavelengths.
Radiant energy is absorbed by the thermopile black surface, thus creating a
difference of temperature between the center of the thermopile (hot junction)
and the pyranometer body (cold junction). Thanks to the Seebeck effect, the
difference of temperature between hot and cold junction is converted into a
difference of potential.
The pyranometer spectral range is determined by the transmission of the two
concentric glass domes, with 50 and 30 mm outer diameters, which also grant
the thermopile a proper thermal insulation from the wind and reduce the
sensitivity to thermal irradiance. Furthermore, the domes protect the
thermopile from the dust which, depositing on the blackened part, could change
its spectral sensitivity.
The special material used to manufacture the domes allows the spectral range
to be extended to short wavelengths starting from 283 nm.
Considering a standard solar spectrum, the portion of solar irradiation
detected by the pyranometer is greater than 99.8%. Figure 3.1 shows the
relative spectral sensitivity of the LPS02… pyranometers (blue line) and the
standard solar spectrum (red line).![Delta OHM LPS02 Series Photometric Probe
- PRINCIPLE](https://manuals.plus/wp-content/uploads/2023/09/Delta-OHM-LPS02
-Series-Photometric-Probe-PRINCIPLE.png) Fig. 3.1: LPS02… relative spectral
sensitivity and standard solar spectrum
An internal compensation circuit minimizes the change of sensitivity with temperature.
To prevent condensation from forming on the internal side of the dome under certain climatic conditions, silica-gel is inserted inside the pyranometer to absorb moisture.
INSTALLATION
-
The pyranometer must be mounted in an easy-to-reach location in order to clean the dome regularly and carry out maintenance. At the same time, make sure that no buildings, constructions, trees or obstructions exceed the horizontal plane where the pyranometer lies. If this is not possible, select a site where obstructions in the path of the sun from sunrise to sunset do not exceed 5 degrees of elevation. N.B.: The presence of obstructions on the horizon line affects significantly the measurement of direct irradiance.
-
The pyranometer must be located far from any kind of obstruction, which might reflect sunlight (or sun shadow) onto the pyranometer itself.
-
The mast height does not exceed the pyranometer plane to avoid measurement errors caused by any reflection or shadow of the mast itself.
-
In compliance with ISO TR9901 standard and WMO recommendations, if the pyranometer is used without the solar radiation protection screen, it must be positioned so that the connector points to the North Pole, if the instrument is used in the Northern Hemisphere, and to the South Pole, if used in the Southern Hemisphere. In any case, it is better to follow this recommendation even when the screen is used.
-
For fixing, use the two M5 or the two M8 holes in the lower part of the pyranometer. For an accurate horizontal positioning, adjust the height of the two lower feet with knurled ring, using the bubble level integrated in the pyranometer.
Note: for horizontal positioning it is preferable to use the bubble level also in models equipped with a tilt sensor, as it is more accurate; use the tilt sensor for positioning monitoring after installation. Use the tilt sensor for installation only if the pyranometer must be positioned tilted with respect to the horizontal plane. -
It is preferable to thermally insulate the pyranometer from its mounting bracket by securing it not with the base directly in contact with the support plate, but by leaving a layer of air in between (for this purpose, always use the feet even if the installation is not horizontal), while at the same time ensuring that there is good electrical contact to ground.
4.1 OPTIONAL MOUNTING SUPPORTS 4.2 ELECTRICAL CONNECTIONS
The metallic housing of the pyranometer should preferably be grounded ( **)
locally. In this case, do not connect the wire of the cable corresponding to
the housing to prevent ground loops.
Only if it is not possible to ground locally the metallic case of the
pyranometer, connect the wire of the cable corresponding to the housing to
ground.
Internally there are surge protection devices connected to the housing.
Grounding the housing allows the correct protection functionality of the
devices.
Connector pinout:
LPS02M0x**
Pin| Function| CPM12-5…
wire color
---|---|---
1| Power supply positive (+Vdc)| Brown
2| Power supply negative (GND)| White
3| RS485 Data +| Blue
4| RS485 Data –| Black
5| Digital ground (DGND)| Grey
| Connector shell Pyranometer housing| Yellow/Green
LPS02MAx
Pyranometer male connector
Pin| Function| CPM12-8…
wire color
---|---|---
1| Power supply negative (GND)| White
2| Power supply positive (+Vdc)| Brown
3| Digital ground (DGND)| Green
4| RS485 Data –| Yellow
5| RS485 Data +| Grey
6| Analog ground (AGND)| Pink
7| Analog output positive (AOUT)| Blue
8| Not connected| Red
| Connector shell Pyranometer housing| Yellow/Green
Pyranometer male connector Connections: RS485 output:
The RS485 output is isolated. Before connecting the pyranometer to the RS485
network, set the address and the communication parameters, if different from
the factory preset (see “Configuration” chapter).
Analog output:
In the LPS02MAx models the type of analog output is configurable (default 4…20
mA, see “Configuration” chapter). The pyranometer power supply and the load
resistance vary according to the type of analog output configured:
Analog output| Power supply required| Load
resistance
---|---|---
0…20 mA| 10…30 Vdc| ≤ 500 Ω
4…20 mA| 10…30 Vdc| ≤ 500 Ω
0…1 V| 10…30 Vdc| ≥ 100 kΩ
0…5 V| 10…30 Vdc| ≥ 100 kΩ
0…10 V| 15…30 Vdc| ≥ 100 kΩ
In the event of an anomaly in the measurement (detected measurement outside the measuring range), the output goes to a value 10% higher than the full scale (e.g., 11 V if the output is 0…10 V or 22 mA if the output is 4…20 mA).
CONFIGURATION
It is possible to change the serial communication parameters (Modbus address,
Baud Rate, parity/stop bit) and, for models with analog output, the type of
analog output and the global irradiance measuring range corresponding to the
analog output.
The configuration of the pyranometer can be done:
- With the aid of DATAsense PC application software (see the software online help), downloadable from Delta OHM website.
- By sending serial commands from a PC, via a standard communication program (see the chapter “ASCII proprietary protocol”).
- Via the “Holding Registers” in MODBUS-RTU mode (only for the serial communication parameters, see the chapter “Modbus-RTU protocol”).
By default, the instrument has MODBUS address 1 and communication parameters 19200, 8E1.
Analog output (only LPS02MAx):
By default, the analog output is 4…20 mA → 0…2000 W/m 2.
It is possible:
- to associate the analog output to a different global irradiance range, within the full measuring range;
- change the output type (possible outputs 4…20 mA, 0…20 mA, 0…1 V, 0…5 V or 0…10 V);
- to reverse the direction of the output, so that the output decreases as the measurement increases.
Connection to PC:
To connect the pyranometer to a PC USB port, to check or change the
configuration, the CP24B-5 (LPS02M0x) or CP24B-8 (LPS02MAx) optional cables
can be used, which also allow the pyranometer to be powered via the USB port.
To use the CP24B-x cables, the related USB drivers must be installed in the
PC.
Alternatively, it is possible to use a standard RS485/USB or RS485/RS232
converter, powering the pyranometer separately (the minimum supply voltage is
7 V).
ASCII PROPRIETARY PROTOCOL
To communicate with the pyranometer via the ASCII proprietary protocol:
-
Connect the pyranometer to the PC and start a standard serial communication program.
-
In the serial communication program, set the Baud Rate 57600, the parameters 8N2 and the COM port number to which the pyranometer is connected.
-
Power the pyranometer (or power cycle if already powered) and send the command @ within 5 seconds from the instrument power on (the pyranometer replies &| if the command @ is recognized).
Note: if the CP24B-x cable is used, to power cycle the pyranometer, disconnect the cable for a few seconds from the PC USB port, then reconnect it. -
Send the command CAL USER ON (the pyranometer replies CAL USER ON;USER ON) to enable the configuration change. The command CAL USER ON is not required only for reading the settings.
-
Send the commands described in the tables below.
The command CAL USER ON is automatically disabled after a few minutes of
inactivity.
The command CAL USER ON can be disabled immediately by sending the command CAL
EXIT.
Ping:
Command | Reply | Description |
---|---|---|
P0 | P0;& | Ping. |
Pyranometer general information:
Command | Reply | Description |
---|---|---|
G0 | G0; model | Model |
G1 | G1; sub-model | Sub-model |
G2 | G2;nnnnnnnn | Serial number |
G3 | G3;xx.yy | Firmware revision |
G4 | G4;aaaa/mm/gg | Firmware revision date |
G5 | G5;xx.yy | Hardware revision |
G6 | G6;nnnnn | Operating time in days from first power on |
G7 | G7;nnnnn | Operating time in days from last power on |
GD | GD;aaaa/mm/gg hh:mm:ss | Factory calibration date and time |
User code:
The user code is an alphanumeric string of up to 8 characters that the user
can set to identify the pyranometer with a mnemonic name.
Command | Reply | Description |
---|---|---|
CUCnnnnnnnn | CUC;& | Sets nnnnnnnn as user code. Default =blank |
RUC | RUC;nnnnnnnn | Reads the user code. |
RS485 Modbus-RTU communication parameters:
Command | Reply | Description |
---|---|---|
CMAn | CMA;& | Sets the Modbus-RTU address (1…247) to n. Default = 1 |
RMA | RMA;n | Reads the Modbus-RTU address. |
CMBn | CMB;& | Sets the Baud Rate: |
▪ 9600 if n=0
▪ 19200 if n=1 ( default )
▪ 38400 if n=2
▪ 57600 if n=3
▪ 115200 if n=4
RMB| RMB;n|| Reads Baud Rate setting.
CMPn| CMP;&|| Sets parity and stop bits (data bits = 8 fixed):
▪ 8N1 if n=0 ▪ 8N2 se n=1
▪ 8E1 if n=2 ( default ) ▪ 8E2 se n=3
▪ 8O1 if n=4 ▪ 8O2 se n=5
RMP| RMP;n|| Reads the setting of parity and stop bits.
CMWn| CMW;&|| Sets waiting time after transmission with Modbus-RTU protocol:
▪ Immediate reception if n=0 (violates protocol)
▪ Waiting 3.5 characters if n=1 (respects protocol)
Default : Waiting 3.5 characters (n=1)
RMW| RMW;n|| Reads the setting of waiting time after transmission with Modbus-
RTU protocol.
Analog output (only LPS02MA…):
Command | Reply | Description |
---|---|---|
CASn | CAS;& | Sets the analog output type: |
▪ 0…20 mA if n=0
▪ 4…20 mA if n=1 ( default )
▪ 0…1 V if n=2
▪ 0…5 V if n=3
▪ 0…10 V if n=4
RAS| RAS;n|| Reads the type of analog output set.
CAInnnn| CAI;&|| Sets nnnn as irradiance minimum value in W/m2 for the analog
output. Min=-200, default = 0
RAI| RAI;nnnn|| Reads the irradiance minimum value in W/m2 for the analog
output.
CAFnnnn| CAF;&|| Sets nnnn as irradiance maximum value in W/m2 for the analog
output. Max=4000, default = 2000
RAF| RAF;nnnn|| Reads the irradiance maximum value in W/m2 for the an- alog
output.
CAin| CAi;&|| Sets the direct or reversed correspondence between ana- log
output and irradiance:
▪ If n=0: Min. output Þ Min. irradiance Max. output Þ Max. irradiance
▪ If n=1: Min. output Þ Max. irradiance Max. output Þ Min. irradiance
Default : Direct correspondence (n=0)
RAi| RAi;n|| Reads the type of correspondence (direct or reversed) between
analog output and irradiance.
Units of measurement:
Changing the temperature units of measurement affects the Modbus protocol
only. The temperature measurement provided by the ASCII proprietary protocol
(commands S0/S1) is always in °C.
Command | Reply | Description |
---|---|---|
TTn | WUT;& | Sets the temperature unit of measurement: |
▪ °C if n=0 ( default )
▪ °F if n=1
▪ K if n=2
RUT| RUT;n|| Reads the temperature unit of measurement.
Measurements reading:
Command | Reply | Description |
---|---|---|
S0 | S0; meas | Prints the measurements in the following sequence: |
▪ Temperature compensated irradiance in W/m2 ( it takes into account the
change in sensor sen- sitivity as temperature changes )
▪ Nominal irradiance in W/m2 ( calculated considering the sensor nominal
sen- sitivity at the calibration temperature: ~ 23 °C )
▪ Signal in mV generated by the thermopile
▪ Internal temperature in °C
▪ Internal relative humidity in %
▪ Internal pressure in hPa
▪ Tilt angle ( only LPS02MxT )
▪ Power supply voltage
If the automatic sending of the measurements is enabled (command S1), sending
S0 disables the automatic send- ing.
S1| S1; meas || Enables the automatic sending of the measurements, once per
second.
Diagnostics alarm thresholds:
Command | Reply | Description |
---|---|---|
WAL1n…n | WAL1;& | Sets to n…n the operating time alarm threshold from first |
power on (0…65535 days, default=730 days à 2 years).
AL1| AL1;n…n|| Reads the operating time alarm threshold from first power on.
WAL2n…n| WAL2;&|| Sets to n…n the operating time alarm threshold from last
power on (0…65535 days, default=730 days à 2 years).
AL2| AL2;n…n|| Reads the operating time alarm threshold from last power on.
WAL3n…n| WAL3;&|| Sets to n…n, in the set unit of measurement, the inter- nal
temperature alarm threshold (0…150 °C, default=80 °C).
AL3| AL3;n…n|| Reads the internal temperature alarm threshold.
WAL4n…n| WAL4;&|| Sets to n…n% the internal relative humidity alarm threshold
(0…100%, default=25%).
AL4| AL4;n…n|| Reads the internal relative humidity alarm threshold.
Command| Reply| Description
---|---|---
WAL5n…n| WAL5;&|| Sets to n…n hPa the internal pressure alarm threshold
(800…1100 hPa, default=1100 hPa).
AL5| AL5;n…n|| Reads the internal pressure alarm threshold.
All alarm thresholds are integer values with resolution 1 (1 day, 1 °C/°F/K, 1
%RH, 1 hPa).
The alarm condition occurs when the parameter becomes greater than the set
threshold.
MODBUS-RTU PROTOCOL
By default, the pyranometer has Modbus address 1 and communication parameters
19200, 8E1. The address and the communication parameters can be changed by
using the appropriate serial commands of the proprietary protocol or,
alternatively, directly with Modbus commands by changing the value of the
Holding Registers described later.
The Modbus-RTU protocol is active after a few seconds from the sensor power
on.
The delay between the reception of a query from the master device and the
start of the pyranometer reply is less than 10 ms. Below is the list of
registers.
Input Registers:
Address | Description | Format |
---|
MEASUREMENTS
1| Temperature compensated irradiance in W/m2 (x10)
( it takes into account the change in sensor sensitivity as temperature
changes )| 32-bit Integer
3| Nominal irradiance in W/m2 (x10)
( calculated considering the sensor nominal sensitivity at the calibration
temperature: ~ 23 °C )| 32-bit Integer
6| Internal relative humidity in % (x10)| 16-bit Integer
7| Internal temperature in the set unit of measurement (x10)| 16-bit Integer
8| Internal pressure in hPa (x10)| 16-bit Integer
9| Signal in mV generated by the thermopile (x1000)| 32-bit Integer
11| Tilt angle ( only LPS02MxT ) (x10)| 16-bit Integer
PYRANOMETER GENERAL INFORMATION
16…25| Model (20 characters)| String
26…35| Sub-model (20 characters)| String
36…39| Serial number (8 characters)| String
40…43| Firmware revision (8 characters)| String
44…47| Hardware revision (8 characters)| String
CALIBRATION HISTORY
50| Sensitivity of last calibration in µV/Wm-2 (x1000)| 32-bit Integer
52…55| Date of last calibration (yyyymmdd)| String
56| Sensitivity of historical calibration 1 in µV/Wm-2 (x1000)| 32-bit Integer
58…61| Date of historical calibration 1 (yyyymmdd)| String
62| Sensitivity of historical calibration 2 in µV/Wm-2 (x1000)| 32-bit Integer
64…67| Date of historical calibration 2 (yyyymmdd)| String
68| Sensitivity of historical calibration 3 in µV/Wm-2 (x1000)| 32-bit Integer
70…73| Date of historical calibration 3 (yyyymmdd)| String
74| Sensitivity of historical calibration 4 in µV/Wm-2 (x1000)| 32-bit Integer
Address| Description| Format
---|---|---
76…79| Date of historical calibration 4 (yyyymmdd)| String
80| Sensitivity of historical calibration 5 in µV/Wm-2 (x1000)| 32-bit Integer
82…85| Date of historical calibration 5 (yyyymmdd)| String
OPERATING TIME
100| Operating time in days from first power on| 16-bit Integer
101| Operating time in days from last power on| 16-bit Integer
Notes on the registers format:
-
To read a 32-bit integer value, two consecutive registers starting from the one indicated must be accessed. The register with lower address contains the most significant bits.
Example: the temperature compensated irradiance, for ex. 50.1 W/m 2 , is available in the registers with address 1 and 2.Register address| 1| 2
---|---|---
Register content (Hex)| 0000| 01F5
Read value| 0x000001F5 = 501 = 50.1 W/m2 -
The alphanumeric strings are contained in a series of 16-bit registers. Each register contains 2 characters of the string: the most significant 8 bits contain the ASCII code of the first character, the least significant 8 bits contain the ASCII code of the next character. The start character of the string is in the register of the series with the lowest address.
Example: the pyranometer model, for ex. LPS02MAT, is available in the registers with address from 16 to 25.
Register address| 16| 17| 18| 19| 20| 21|
22| 23| 24| 25
---|---|---|---|---|---|---|---|---|---|---
Register content (Hex)| 4C50| 5330| 324D| 4154| 0000| 0000| 0000| 0000| 0000|
0000
Read value| L| P| S| 0| 2| M| A| T| | | | | | | | | | | |
Discrete inputs:
Address | Description | Format |
---|---|---|
0 | Operating time alarm from first power on | Bit |
1 | Operating time alarm from last power on | Bit |
2 | Internal temperature alarm | Bit |
3 | Internal relative humidity alarm | Bit |
4 | Internal pressure alarm | Bit |
The value of a “Discrete input”, normally at 0, becomes 1 when the alarm
threshold set with the relative “Holding register” is exceeded.
Holding Registers:
Address | Description | Format |
---|---|---|
0 | RS485 Modbus-RTU Baud Rate: 0=9600 |
1=19200 (default)
2=38400
3=57600
4=115200| 16-bit Integer
1| RS485 Modbus-RTU parity and stop bits: 0=8N1
1=8N2
2=8E1 (default) 3=8E2
4=8O1
5=8O2| 16-bit Integer
2| Modbus-RTU address (1…247, default=1).| 16-bit Integer
5| Temperature unit of measurement: 0=°C (default)
1=°F
2=K| 16-bit Integer
6| Operating time alarm threshold from first power on (0…65535 days,
default=730 days à 2 years)| 16-bit Integer
7| Operating time alarm threshold from last power on (0…65535 days,
default=730 days à 2 years)| 16-bit Integer
8| Internal temperature alarm threshold in the set unit of meas- urement
(0…150 °C, default=80 °C)| 16-bit Integer
9| Internal relative humidity alarm threshold in % (0…100 %, default=25%)|
16-bit Integer
10| Internal pressure alarm threshold in hPa (800…1100 hPa, de- fault=1100
hPa)| 16-bit Integer
All alarm thresholds are integer values with resolution 1 (1 day, 1 °C/°F/K, 1 %RH, 1 hPa).
MEASUREMENT WITH ANALOG OUTPUT (only LPS02MA…)
Calculation of the global irradiance Ee (W/m 2 ) as a function of the analog output value Vout (in V) or Iout (mA).
Analog output | Global irradiance |
---|---|
0…20 mA | Ee = Eis + [(Efs – Eis) · Iout/20] |
4…20 mA | Ee = Eis + [(Efs – Eis) · (Iout – 4)/16] |
0…1 V | Ee = Eis + [(Efs – Eis) · Vout] |
0…5 V | Ee = Eis + [(Efs – Eis) · Vout/5] |
0…10 V | Ee = Eis + [(Efs – Eis) · Vout/10] |
Where Eis and Efs are respectively the global irradiance (in W/m 2 )
corresponding to the analog output initial and full scale.
Considering the default values Eis = 0 and Efs = 2000 W/m 2 , the previous
formulas can be simplified into the following ones:
Analog output | Global irradiance |
---|---|
0…20 mA | Ee = 100 · Iout |
4…20 mA | Ee = 125 · (Iout – 4) |
0…1 V | Ee = 2000 · Vout |
0…5 V | Ee = 400 · Vout |
0…10 V | Ee = 200 · Vout |
USE OF THE DIAGNOSTIC SENSORS
The internal temperature, relative humidity, pressure and tilt (only LPS02MxT)
diagnostic sensors allow keeping the pyranometer operating conditions under
control all the time and foresee any maintenance intervention in advance, thus
ensuring always reliable measurements.
Internal temperature
As a rule, the internal temperature of the pyranometer is on average 5 to 10
°C higher than the external ambient temperature. Temperatures that are
excessively lower or higher than indicated may be a sign of malfunctions.
Monitoring the internal temperature therefore makes it possible to determine
whether the irradiance measurement can be considered reliable.
Internal relative humidity
To minimize condensation and keep measurements accurate, desiccant silica-gel
is provided inside the pyranometer base to absorb moisture. The silica-gel
life is at least 10 years. The long-term monitoring of the internal relative
humidity of the pyranometer allows the efficiency of the silica-gel to be
checked. A progressive upward trend in relative humidity indicates the
progressively decreasing ability of silica-gel to absorb moisture.
The internal relative humidity depends not only on the saturation level of the
silica-gel but also on the temperature of the pyranometer; therefore, short-
term humidity monitoring is not particularly significant in determining the
condition of the silica-gel. Relative humidity monitoring can be annual.
It is advisable to detect the relative humidity during the night, when the
temperature is lower and the relative humidity is higher. Silica-gel can be
considered close to saturation when the internal relative humidity is
persistently above 50% at temperatures below 20 °C.
Internal pressure
Monitoring the internal pressure of the pyranometer allows the housing to be
checked for tight seal (no leakage). The pressure/temperature ratio should
remain approximately constant.
Tilt
Monitoring the inclination angle of the pyranometer installation allows for
the detection of unwanted displacements that may occur in the long term or as
a result of impacts suffered by the installation.
Take the measurement of the Tilt sensor immediately after installation and
consider it as a reference for subsequent measurements.
Alarm thresholds
Thresholds can be defined for internal temperature, relative humidity and
pressure.
When the thresholds are exceeded an alarm condition is generated, which can be
read via the Modbus “Discrete inputs” or the DATAsense software.
The thresholds can be set via the Modbus “Holding registers”, the
WAL3/WAL4/WAL5 serial commands or the DATAsense software.
MAINTENANCE
In order to grant measurements high accuracy, it is important to keep the
outer glass dome clean. Consequently, the more the dome will be kept clean,
the more measurements will be accurate.
You can wash it using water and standard papers for lens. If necessary, use
pure ETHYL alcohol. After using alcohol, clean again the dome with water only.
To minimize condensation and keep measurements accurate, desiccant silica-gel
is provided inside the pyranometer base to absorb moisture. The silica-gel
life is at least 10 years and can be replaced by the user.
To replace the silica-gel, unscrew the 4 screws that fix the base to the main
body of the pyranometer; remove the silica-gel sachet and insert a new sachet,
then screw the pyranometer base back on.
Warning: the silica-gel replacement must be done in an ESD-safe
environment.
To exploit all the pyranometer features, it is highly recommended that the
calibration be checked annually.
The pyranometer provides the operating time in days since first and last power
on, and allows time alarm thresholds to be set to alert the user of the need
for periodic verification or maintenance. The exceeding of thresholds can be
read via Modbus “Discrete inputs” or DATAsense software. The thresholds can be
set via Modbus “Holding registers”, WAL1/WAL2 serial commands, or DATAsense
software.
SAFETY INSTRUCTIONS
The pyranometer proper operation and operating safety can be ensured only in
the climatic conditions specified in this manual and if all standard safety
measures as well as the specific measures described in this manual are
followed.
Do not use the instruments in places where there are:
- Corrosive or flammable gases.
- Direct vibrations or shocks to the instrument.
- High-intensity electromagnetic fields, static electricity.
User obligations
The instrument operator shall follow the directives and regulations below that refer to the treatment of dangerous materials:
- EU directives on workplace safety.
- National law regulations on workplace safety.
- Accident prevention regulations.
ACCESSORIES ORDERING CODES
The pyranometer is supplied with solar radiation protection screen, M12 female
free connector (only if the optional cable is not ordered), calibration report
and PC application software downloadable from Delta OHM website.
Cables and fixing accessories must be ordered separately.
Fixing accessories
LPS1| Fixing bracket for Ø 40…50 mm mast. Installation on horizontal or
vertical mast.
---|---
LPS5| Adjustable holder for mounting the pyranometer in an inclined position
on Ø 40…50 mm mast.
Installation cables
CPM12-5…| Cable with 5-pole M12 connector on one end, open wires on the other
end. Length 5 m (CPM12-5.5) or 10 m (CPM12-5.10). For LPS02M0…
CPM12-8…| Cable with 8-pole M12 connector on one end, open wires on the other
end. Length 5 m (CPM12-8.5) or 10 m (CPM12-8.10). For LPS02MA…
PC connecting cables
CP24B-5| PC connecting cable for the configuration of the pyranometer. With
built-in RS485/USB converter. 5-pole M12 connector on sensor side and A-type
USB connector on PC side. For LPS02M0…
CP24B-8| PC connecting cable for the configuration of the pyranometer. With
built-in RS485/USB converter. 8-pole M12 connector on sensor side and A-type
USB connector on PC side. For LPS02MA…
Spare parts
LPSP1A| UV-resistant solar radiation protection screen.
LPG| Silica-gel (5 sachets).
DELTA OHM metrology laboratories LAT N° 124 are ISO/IEC 17025 accredited by ACCREDIA for Temperature, Humidity, Pressure, Photometry / Radiometry, Acous- tics and Air Velocity. They can supply calibration certificates for the accredited quantities.
WARRANTY
Delta OHM is required to respond to the “factory warranty” only in those cases
provided by Legislative Decree 6 September 2005 – n. 206. Each instrument is
sold after rigorous inspections;
if any manufacturing defect is found, it is necessary to contact the
distributor where the instrument was purchased from. During the warranty
period (24 months from the date of invoice) any manufacturing defects found
will be repaired free of charge. Misuse, wear, neglect, lack or inefficient
maintenance as well as theft and damage during transport are excluded.
Warranty does not apply if changes, tampering or unauthorized repairs are made
on the product. Solutions, probes, electrodes and microphones are not
guaranteed as the improper use, even for a few minutes, may cause irreparable
damages.
Delta OHM repairs the products that show defects of construction in accordance
with the terms and conditions of warranty included in the manual of the
product. For any dispute, the competent court is the Court of Padua. The
Italian law and the “Convention on Contracts for the International Sales of
Goods” apply.
TECHNICAL INFORMATION
The quality level of our instruments is the result of the continuous product
development. This may lead to differences between the information reported in
the manual and the instrument you have purchased. In case of discrepancies
and/or inconsistencies, please write to
sales@deltaohm.com.
Delta OHM reserves the right to change technical specifications and dimensions
to fit the product requirements without prior notice.
DISPOSAL INFORMATION
**** Electrical and electronic equipment marked with specific symbol in
compliance with 2012/19/EU Directive must be disposed of separately from
household waste.
European users can hand them over to the dealer or to the manufacturer when
purchasing a new electrical and electronic equipment, or to a WEEE collection
point designated by local authorities. Illegal disposal is punished by law.
Disposing of electrical and electronic equipment separately from normal waste
helps to preserve natural resources and allows materials to be recycled in an
environmentally friendly way without risks to human health.
V1.3
07/2023
GHM GROUP – Delta OHM | Delta Ohm S.r.l. a socio unico
Via Marconi 5 | 35030 Caselle di Selvazzano | Padova | ITALY
Phone +39 049 8977150 | Fax +39 049 635596
www.deltaohm.com | sales@deltaohm.com