GHM DeltaOHM LPPYRA12 Operating Manual
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GHM DeltaOHM LPPYRA12 Operating Manual

Pyranometer
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Operating manual
Pyranometer
LPPYRA12
www.deltaohm.com
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Summary of Contents for GHM DeltaOHM LPPYRA12

  • Page 1 English Operating manual Pyranometer LPPYRA12 www.deltaohm.com Keep for future reference.

  • Page 2: Table Of Contents

    TABLE OF CONTENTS INTRODUCTION ....................3 WORKING PRINCIPLE ................... 4 INSTALLATION ..................... 5 ................. 6 OUNTING THE SHADOW RING ......7 OSITIONING THE INSTRUMENT FOR THE DIFFUSE RADIATION MEASUREMENT ELECTRICAL CONNECTIONS ................11 LPPYRA12 ................... 11 CONNECTIONS LPPYRA12AC[4] ................12 CONNECTIONS LPPYRA12AV[4] ................

  • Page 3: Introduction

    INTRODUCTION LPPYRA12 pyranometer measures the irradiance on a flat surface (W/m ). Thanks to the shadow-ring, LPPYRA12 measures the diffuse solar radiation eliminating the con- tribution of direct irradiance. LPPYRA12 is equipped with a Spectrally Flat Class B (First Class) pyranometer (LPPY- RA02) in accordance with ISO 9060:2018 and with the criteria of the WMO “Guide to Meteorological Instruments and Methods of Observation”.

  • Page 4: Working Principle

    2 WORKING PRINCIPLE LPPYRA12 pyranometer is based on a thermopile sensor. The thermopile sensitive sur- face is coated with a black matt paint, which allows the pyranometer not to be selec- tive at different wavelengths. The pyranometer spectral range is determined by the transmission of the two glass domes type K5.

  • Page 5: Installation

    3 INSTALLATION Before installing the pyranometer, refill the cartridge containing silica-gel crystals. Sil- ica gel absorbs humidity in the dome chamber and prevents, in particular climatic conditions, condensation on the internal walls of the domes and measurement altera- tion. Do not touch the silica gel crystals with your hands while refilling the cartridge. Carry out the following instructions in an environment as drier as possible: 1.

  • Page 6: Ounting The Shadow Ring

    • The pyranometer must be mounted in an easy-to-reach location in order to clean the dome regularly and adjust the height of the shadow ring. At the same time, make sure that no buildings, constructions, trees or obstructions exceed the hori- zontal plane where the pyranometer lies.
  • Page 7 3.2 P OSITIONING THE INSTRUMENT FOR THE DIFFUSE RADIATION MEASUREMENT The shadow ring particular geometry allows intercepting the solar direct radiation dur- ing the whole day without adjustments. The base of the instrument has to be mounted parallel to the ground by adjusting the screw with ring nut and with the aid of the levelling device integrated in the instrument.
  • Page 8 Adjusting the shadow ring tilt: 1. Check that the sliding bars and the long side of the pyranometer support be parallel (instruments are supplied factory aligned). 2. Mount and fix the pyranometer to the goniometer. 3. Position the goniometer in such a way to read on its scale the latitude of the instal- lation site.
  • Page 9 TABLE 1A VALID ONLY FOR PASSIVE LPPYRA12 (no AC/AV/S/S12 versions) The table shows the values to which the graduated sliding bars must be set for the different solar declinations and for the two hemispheres. Value to be set on the Value to be set on the Date Solar...
  • Page 10 TABLE 1B VALID FOR ACTIVE VERSIONS (AC/AV/S/S12) The table shows the values to which the graduated sliding bars must be set for the different solar declinations and for the two hemispheres. Value to be set on the Value to be set on the Date Solar sliding bars (mm) if...

  • Page 11: Electrical Connections

    4 ELECTRICAL CONNECTIONS LPPYRA12, LPPYRA12AC[4] and LPPYRA12AV[4] have a 4-pole connector and use the CPM12AA4... optional cables, with 4-pole connector on one side and open wires on the other side. LPPYRA12S and LPPYRA12S12 have a 8-pole connector and use the CPM12-8D... optional cables, with 8-pole connector on one side and open wires on the other side.

  • Page 12: Lppyra12

    4.2 LPPYRA12AC[4] CONNECTIONS The pyranometer LPPYRA12AC[4] has 4…20 mA output and requires 10…30 Vdc ex- ternal power supply. It is to be connected to a power supply and an instrument with 4…20 mA input as shown in fig. 4.2. The load resistance of the instrument reading the signal must be ≤...

  • Page 13: Lppyra12S

    4.4 LPPYRA12S CONNECTIONS The pyranometer LPPYRA12S has RS485 Modbus-RTU output and requires 5…30 Vdc external power supply. It is to be connected to a power supply and to a PLC, a data logger or a RS485/USB or RS485/RS232 converter for PC as shown in fig. 4.4.

  • Page 14: Lppyra12S12

    4.5 LPPYRA12S12 CONNECTIONS The pyranometer LPPYRA12S12 has SDI-12 output and requires 7…30 Vdc external power supply. It is to be connected to a power supply and to an acquisition system (data logger) as shown in fig. 4.5. Connector Function Cable color Power supply negative (GND) Blue SDI-12 output negative...

  • Page 15: Lppyra12Acs

    4.6 LPPYRA12ACS[4] CONNECTIONS The pyranometer LPPYRA12ACS[4] has two outputs: • One 4…20 mA output, requiring 10…30 Vdc external power supply. It is to be connected to a power supply and an instrument with 4…20 mA input as shown in fig. 4.6. The load resistance of the instrument reading the signal must be ≤ 500 Ω. •...

  • Page 16: Measurement In The Models With Analog Output

    5 MEASUREMENT IN THE MODELS WITH ANALOG OUTPUT Below are the ways to calculate the global irradiance in the models with analog output LPPYRA12, LPPYRA12AC[S][4] and LPPYRA12AV[4]. 5.1 LPPYRA12 Each pyranometer is distinguished by its own sensitivity (or calibration factor) S ex- pressed in µV/(Wm ) and shown in the label on the pyranometer (and in the calibra- tion report).

  • Page 17: Rs485 Modbus-Rtu Output

    6 RS485 MODBUS-RTU OUTPUT Before connecting the pyranometer to the RS485 network, an address must be assigned and the communication parameters must be set, if different from the factory preset. 6.1 S ETTING THE COMMUNICATION PARAMETERS Connect the pyranometer to the PC in one of the following two ways: A.
  • Page 18 4. Within 10 seconds from the pyranometer power on, send the @ command and press Enter. Note: if the pyranometer does not receive the @ command within 10 seconds from power on, the RS485 MODBUS mode is automatically activated. In such a case, it is necessary to switch off and on again the pyranometer.

  • Page 19: Rtu Protocol

    6.2 R -RTU EADING THE MEASURES WITH THE ODBUS PROTOCOL In MODBUS mode, you can read the values measured by the pyranometer through the function code 04h (Read Input Registers). The following table lists the quantities available with the appropriate register address: Number Address Quantity...

  • Page 20: Sdi-12 Output

    7 SDI-12 OUTPUT The LPPYRA12S12 pyranometers are compatible with version 1.3 of SDI-12 protocol. The protocol communication parameters are: Baud rate = 1200. Data bits = 7, Parity = Even, Stop bits = 1. The communication with the instrument is performed by sending a command in the following form: <Address><Command>! with <Address>...
  • Page 21 Command Instrument reply Description a<CR><LF> Request of the address of the instrument. If more than one sensor is connected to the bus, a conflict occurs. START MEASUREMENT AND TYPE START CONCURRENT MEASUREMENT COMMANDS Irradiance, signal internal level and internal temperature atttn<CR><LF>...
  • Page 22 Command Instrument reply Description Internal temperature aM2! atttn<CR><LF> Request to execute the measurement. aC2! with: ttt = number of seconds necessary for the in- strument to make the measure available (3 characters) n = number of detected variables (1 character for aM2!, 2 characters for aC2!) Note: ttt = 000 means datum immediately available.
  • Page 23 1) Send the command aXSCAL USER ON! (note: a=instrument address). 2) Send the command aXSCFD! (to set °C) or aXSCFE! (to set °F). 3) Send the command aXSCAL END! For more information about the SDI-12 protocol, visit the website "www.sdi-12.org". LPPYRA12 V2.5...

  • Page 24: Measurement Correction

    8 MEASUREMENT CORRECTION Diffuse radiation is measured by eliminating the contribution of direct radiation through the shadow ring. As besides the direct radiation the shadow ring intercepts part of the diffuse light, it is necessary to correct the measured values. The percentage of diffuse radiation intercepted by the shadow ring changes during the year, because the position that the ring has with respect to the pyranometer changes.
  • Page 25 TABLE 2 Correction factor C for installation in the Northern hamisphere. Northern latitude Solar declination 1.11 1.10 1.09 1.09 1.08 1.07 1.06 1.05 1.04 1.03 1.11 1.11 1.10 1.09 1.08 1.07 1.06 1.05 1.04 1.03 1.12 1.11 1.10 1.10 1.09 1.08 1.07 1.06...
  • Page 26 TABLE 3 Correction factor C for installation in the Southern hamisphere. Southern latitude Solar declination 1.11 1.10 1.09 1.09 1.08 1.07 1.06 1.05 1.04 1.03 1.11 1.11 1.10 1.09 1.08 1.07 1.06 1.05 1.04 1.03 1.12 1.11 1.10 1.10 1.09 1.08 1.07 1.06...

  • Page 27: Maintenance

    9 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 measure- ments will be accurate. You can wash it using water and standard papers for lens. If necessary, use pure ETHYL alcohol.

  • Page 28: Technical Specifications

    10 TECHNICAL SPECIFICATIONS Sensor Thermopile Typical sensitivity 6÷12 µV/Wm 33÷45 Ω Impedance Measuring range 0÷2000 or 0÷4000 W/m depending on model Viewing angle 2π sr Spectral range (50%) 283÷2800 nm Operating temperature/humidity -40÷80 °C / 0÷100% Output Analog in µV/Wm (LPPYRA12) Analog 4÷20 mA (LPPYRA12AC[S]) Analog 0÷1 V, 0÷5 V or 0÷10 V (LPPYRA12AV)

  • Page 29: Safety Instructions

    11 SAFETY INSTRUCTIONS General safety instructions The instrument has been manufactured and tested in accordance with the safety standard EN61010-1:2010 “Safety requirements for electrical equipment for meas- urement, control and laboratory use” and has left the factory in perfect safety tech- nical conditions.

  • Page 30: Accessories Ordering Codes

    12 ACCESSORIES ORDERING CODES LPSP1 UV-resistant shade disk (spare part). CPM12AA4… Cable with 4-pole M12 connector on one end, open wires on the other end. Length 2 m (CPM12AA4.2), 5 m (CPM12AA4.5) or 10 m (CPM12AA4.10). LPPYRA12, LPPYRA12AC[4] LPPYRA12AV[4]. CPM12-8D… Cable with 8-pole M12 connector on one end, open wires on the other end.
  • Page 32 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 WARRANTY Delta OHM is required to respond to the "factory warranty" only in those cases provided by Legislative Decree 6 September 2005 - n.

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