Kipp&Zonen SHP1 User Manual

Instruction Manual

SHP1 • Smart Pyrheliometer

Instruction Manual - SHP1 - Smart Pyrheliometer

2

Important User Information

.

Dear customer, thank you for purchasing a Kipp & Zonen instrument. It is essential that you read this manual completely for a

full understanding of the proper and safe installation, use, maintenance and operation of your new SHP1 pyrheliometer.

We understand that no instruction manual is perfect, so should you have any comments regarding this manual we will be

pleased to receive them at:

Kipp & Zonen B.V.

Delftechpark 36, 2628 XH Delft, - or P.O. Box 507, 2600 AM Delft, The Netherlands

T: +31 (0) 15 2755 210 F: +31 (0) 15 2620 351 support@kippzonen.com www.kippzonen.com

Warranty and liability

Kipp & Zonen guarantees that the product delivered has been thoroughly tested to ensure that it meets its published speciﬁcations.

The warranty included in the conditions of delivery is valid only if the product has been installed and used according to the

instructions supplied by Kipp & Zonen.

Kipp & Zonen shall in no event be liable for incidental or consequential damages, including without limitation, lost proﬁts, loss

of income, loss of business opportunities, loss of use and other related exposures, however incurred, rising from the faulty and

incorrect use of the product.

Modiﬁcations made by the user may aect the instrument performance, void the warranty, or aect the validity of the CE

declaration or other approvals and compliances to applicable International Standards.

All rights are reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form

or by any means, without authorisation by Kipp & Zonen.

Kipp & Zonen reserves the right to make changes to this manual, brochures, speciﬁcations and other product documentation

without prior notice.

Manual document number: V1405

st

Publication date: 1

May 2014

Instruction Manual - SHP1 - Smart Pyrheliometer

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Instruction Manual - SHP1 - Smart Pyrheliometer

4

Declaration of Conformity

.

We Kipp & Zonen B.V.

Delftechpark 36, 2628 XH Delft P.O. Box 507, 2600 AM Delft The Netherlands

Declare under our sole responsibility that the products:

Models SHP1 Type Smart Pyrheliometer

to which this declaration relates are in conformity with European Harmonised Standards as published in:

Ofﬁcial Journal of the EC, Issue: C288 (30-09-2011)

The compliance of the product has been based on: Emissions EN 61326-1:2006 Immunity EN 61326-1:2006

following the provisions of the directive: EMC-directive 2004/108/EC

st

Delft, 1

B.A.H. Dieterink

President

Kipp & Zonen B.V.

August 2012

Instruction Manual - SHP1 - Smart Pyrheliometer

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Instruction Manual - SHP1 - Smart Pyrheliometer

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Table of Contents

.

Important User Information

.

3.........................................................................................................................................................................................

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3

Declaration of Conformity

Table of Contents

1 Introduction

1.1 Product overview

1.1.1 The SHP1 pyrheliometer

1.1.2 International Standards

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1.2 Key parts of the SHP1 pyrheliometer

2 Installation

2.1 Included with the product

2.2 Tools required

2.3 Location and support

2.3.1 Location

2.3.2 Mounting

2.3.3 Fitting the connector and cable

2.4 Electrical connections

2.5 Power connection

2.6 Data connection

2.7 Analogue output connection

2.8 Calculations

2.8.1 Calculation 0 to 1 Volt version

2.8.2 Calculation 4 to 20 mA version

2.8.3 Recommended cable types

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9

10

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11 12 12

12 12

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13 13

14

15

16

3 Accessories

3.1 Cables

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4 Software installation and conﬁguration

4.1 Set up communication

4.2 Change the Modbus® address

4.3 Instrument data

4.4 Chart

4.5 Data logging

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5 Operation and measurement

5.1 Data collection

5.2 Key parts of SHP1 pyrheliometer

5.2.1 Window

5.2.2 Detector

5.2.3 Housing

5.2.4 Drying cartridge

5.2.5 Cable and connector

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6 Maintenance and re-calibration

6.1 Daily maintenance

6.2 Monthly maintenance

6.3 Yearly maintenance

6.4 Calibration

6.4.1 Calibration principle

6.4.2 Calibration traceability to the WRR

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17

19

20 20

21 22 23

25

25 25

25 26 26 26 26

27

27 27 27 27

27

28

7

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7 Speciﬁcations

.

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7.1 Optical and electrical

7.2 Dimensions

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29

29 29

8 Trouble shooting

8.1 Output signal not present or incorrect

8.2 Frequently Asked Questions

9 Customer Support

10. Keyword index

Appendices

A. Modbus®

A.1 Modbus® commands A.2 Input registers A.3 Holding registers A.4 Read input register A.5 Discrete inputs A.6 Coils A.7 Read write holding registers A.8 Read discrete inputs A.9 Read write discrete coils A.10 Requesting serial number A.11 Simple demonstration program

B. Pyrheliometer physical properties

B.1 Spectral range B.2 Sensitivity B.3 Response time B.4 Non-linearity B.5 Tempearture dependence B.6 Operating temperature B.7 Field of view B.8 Maximum irradiance B.9 Non-stability B.10 Spectral selectivity B.11 Environmental B.12 Uncertainty

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C. Pyrheliometer classiﬁcation to ISO 9060:1990

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31

31 31

33

35

37

37 39 39 42 42 43 43

44

45 45

47

47 47 47 47 47 47

48 48 48 48 48 49

49

Using this table Click on any item in the table of contents to be taken directly to the relevant page.

Click on the Kipp & Zonen logo at the bottom of any page to be taken back to the table of contents.

8

1. Introduction

.

Throughout this manual the following symbols are used to indicate to the user important information.

General warning about conditions, other than those caused by high voltage electricity, which may result in physical

injury and/or damage to the equipment or cause the equipment to not operate correctly.

Note Useful information for the user

1.1 Product overview

According to International Standard ISO 9060:1990 and the World Meteorological Organization (WMO) a pyrheliometer is the

designated type of instrument for the measurement of direct solar radiation. The SHP1 pyrheliometer is compliant with the

“First Class” class speciﬁed by the international standards.

This manual, together with the instruction sheet, provides information related to the installation, maintenance, calibration,

product speciﬁcations and applications of the SHP1 pyrheliometer.

If any questions should remain, please contact your local Kipp & Zonen representative or e-mail the Kipp & Zonen customer and product support department at: support@kippzonen.com

Please go to www.kippzonen.com for information about other Kipp & Zonen products, or to check for any updates to this manual

or software.

1.1.1 The SHP1 pyrheliometer

SHP1 pyrheliometer is a high quality radiometer designed for measuring direct short-wave irradiance (radiant ﬂux, W/m²) which

results from the radiant ﬂux from a solid angle of 5 degrees.

SHP1 pyrheliometer features internal digital signal processing and interfaces optimised for industrial data acquisition and control

systems. Kipp & Zonen has developed a smart interface that features RS-485 Modbus® data communication for connection to

programmable logic controllers (PLC’s), inverters, digital control equipment and the latest generation of data loggers. Ampliﬁed

Voltage or Current outputs are also included for devices that have high-level analogue inputs or current loop interfaces.

The SHP1 is available in two versions. The SHP1-V has an analogue voltage output of 0 to 1 V, the SHP1-A has an analogue current

output of 4 to 20 mA. Both have a 2-wire RS-485 interface with Modbus® (RTU) protocol. Both versions have minimised power

consumption and are protected against short circuit and reversed polarity. The digital signal processing provides faster response

times and, with an integrated temperature sensor, individual corrections for the temperature dependence of the detector are made.

To achieve the required spectral characteristics SHP1 uses a quartz window and thermopile detector. The waterproof connectors

have gold-plated contacts.

The pyrheliometer is normally delivered with a waterproof plug pre-wired to a high quality signal cable, typically this is 10 m

long but other lengths are available. The instruments can also be ordered with a plug only, for the user to ﬁt their own cable.

Instruction Manual - SHP1 - Smart Pyrheliometer

9

.

1.1.2 International Standard

For the SHP1 Second Class pyrheliometer ISO standard ISO 9060 applies.

Fully compliant with all ISO 9060:1990 speciﬁcation criteria for an ISO Second Class pyrheliometer, the SHP1 features a

thermocouple sensing element. An integrated temperature sensor with active and individual measured temperature compensation

is included for improved temperature dependence of sensitivity.

1.2 Key parts of the SHP1 pyrheliometer

drying cartridge quartz window

connector

smart interface

detector aperture rings rain shield

alignment aids

housing

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2. Installation

.

Please follow the instructions in this section carefully for the mechanical and electrical installation of the SHP1 pyrheliometer.

Do not turn on power to the instrument until instructed to do so.

Note Do not connect the instrument to a computer until instructed to do so.

Note Do not turn on power to the operating computer until instructed to do so.

2.1 Included with the product

Check the contents of the shipment for completeness (see below) and note whether any damage has occurred during transport. If

there is damage, a claim should be ﬁled with the carrier immediately. In the case of damage and/or the contents are incomplete,

contact your local Kipp & Zonen representative or e-mail the Kipp & Zonen customer and product support department at: support@kippzonen.com

Although a SHP1 pyheliometer is weather-proof and suitable for use in harsh environmental conditions, it has some delicate

mechanical parts. Please keep the original packaging for safe transport of the radiometer to the measurement site, or for use

when returning the radiometer for calibration.

The following items are included with a SHP1 pyrheliometer:

1

Smart pyrheliometer and rain shield

2

Cable, pre-wired with 8-pins connector or connector only for customer cable

3

Calibration certiﬁcate

4

Instruction sheet

5

2 Dessicant bags

6

CD with product documentation and software

1

2

4

3

5

6

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2.2 Tools required

The tool required to mount a SHP1 on a SOLYS 2 or 2AP sun tracker is a 3 mm Allen key. Normally, the drying cartridge for the

SHP1 should be hand-tight, but a 16 mm or 5/8” open-ended wrench / spanner can be used to loosen it.

Check the condition of the desiccant in the SHP1 and replace before installation, if necessary; for example after a long storage

period.

The SHP1 instruction sheet plus the sun tracker manual contain all information to do the installation. When using the digital

output it might be convenient to set the Modbus® address prior to visiting the site, otherwise a computer and RS-485 / USB

converter may be required during installation.

2.3 Location and support

The following steps must be carefully taken for optimal performance of the instrument.

2.3.1 Location

Ideally, the site for the pyrheliometer plus sun tracker should be free from any obstructions to the hemispherical view from the

plane of the detector. If this is not possible, the site should be chosen in such a way that any obstruction over the azimuth range

between earliest sunrise and latest sunset should have an elevation not exceeding 5 ° (the apparent sun diameter is 0.5 °).

Further details for installation of the sun tracker can be found in the manual of the used tracker.

It is evident that the radiometer should be located in such a way that a shadow will not be cast upon it at any time (for example

by masts or ventilation ducts). Note that hot exhaust gas (> 100°C) will produce some radiation in the spectral range of the

radiometer and cause an oset in the measurements. This is important for an accurate measurement of the direct solar radiation.

The radiometer should be readily accessible for cleaning the front window and inspecting the desiccant.

2.3.2 Mounting

The mounting of the SHP1 pyrheliometer is related to the used sun tracker. Therefore we refer to the sun tracker manual for

further instructions on how to mount the SHP1 on the side mounting plate of the sun tracker.

2.3.3 Fitting the connector and cable

Locate the plug correctly in the radiometer socket, it only ﬁts one way, and push it in. Screw the plug locking ring hand-tight.

Over-tightening may damage the waterproof seal. Secure the cable so that it cannot blow in the wind or cause a shadow on the

instrument.

Note The cable should be arranged with a curve below the instrument so that water drips o, rather than running along the

cable up to the connector.

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2.4 Electrical connections

As standard SHP1 pyrheliometers are supplied with a waterproof connector pre-wired to 10 m of high quality yellow cable with 8

wires and a shield covered with a black sleeve. Longer cables are available as options. The colour code of the wires and the

connector pin numbers are shown below and on the instruction sheet.

Special attention is needed to prevent power or ground loops when connecting the SHP1 to multiple readout devices.

Connecting the RS-485 to a grounded circuit and the analogue output to a ﬂoating circuit can cause unacceptable

ground loops. This may cause dierential voltages outside the SHP1 speciﬁcations and will damage the unit. We

recommend using either the analogue or the digital output but not both. The maximum dierential between either

of the Modbus® RS-485 lines (yellow and grey) and the power ground / RS-485 common line (black) is 70 VDC.

Radiometer connection

up to

serial number 144999

0.6

0.4

0.8

0.2

0.0

1.0

V / mA

SHP1-V or SHP1-A SHP1-V or SHP1-A

Modbus® RS-485

wire from power supply ground

to Modbus® ground needed

5 to 30 VDC

power supply

Radiometer connection

starting from

serial numbers 145000

0.6

0.4

0.8

0.2

0.0

1.0

V / mA

Modbus® RS-485

5 to 30 VDC

power supply

RADIOMETER CONNECTION

Wire Function Connect with

Green

3

Brown

6

Yellow

4

Grey

5

White

7

Black

8

Red

1

Blue

2

* Connect to ground if radiometer not grounded

The blue wire is not connect with radiometers with serial number up to 144999

Analogue out V+/4-20 mA(+)

Analogue ground V

Modbus® RS-485

Power 5 to 30 VDC

Power ground / RS-485 Common

Modbus® common / Ground

HousingShield

-

/4-20 mA(-)

(12 V recommended)

Not connectedNone

Ground *

First connect all wires before plugging into the radiometer

The shield of the cable is connected to the aluminium radiometer housing through the connector body. The shield

at the cable end may be connected to ground at the readout equipment. Lightning can induce high voltages in the

shield but these will be led o at the pyrheliometer and data logger.

Note Long cables may be used, but the cable resistance must be smaller than 0.1% of the impedance of the readout

equipment for the analogue outputs and may aect the baud rate of the RS-485 digital connection.

2.5 Power connection

The minimum power supply voltage for a SHP1 pyrheliometer is 5 VDC. However, for optimal performance it is advised to use

12 VDC, especially when long cables are used. 5-volt power can only be used in combination with a short cable, maximum 10 m.

It is advised to protect the output of the power supply with a fast blowing fuse of maximum 250 mA rating.

Typical power consumption SHP1-V

5 VDC max. 50 mW (approx. 10.0 mA)

12 VDC max. 55 mW (approx. 4.5 mA)

24 VDC max. 60 mW (approx. 2.5 mA)

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.

Maximum power consumption and input current.

65 mW and 2 mA at the highest input voltage.

63 mW and 12.5 mA at the lowest input voltage.

The maximum inrush current is 200 mA.

Typical power consumption SHP1-A

5 VDC 77 mW (approx. 28 mA with 100 Ω load resistor)

12 VDC 83 mW (approx. 24 mA with 100 Ω load resistor)

24 VDC 100 mW (approx. 6 mA with 100 Ω load resistor)

The above mW values represent the dissipation within the SHP1-A. For the total power the energy in the load resistor has to

be added.

For supply voltages below 12 Volts or above 20 Volts it is advised to use a load resistor of less than 500 Ω to keep the power

consumption as low as possible.

2.6 Data connection

Connection to a Personal Computer by Universal Serial Bus (USB)

The connection depends on the use of a RS-485 to USB converter.

The converter must have galvanic isolation between the inputs and outputs to prevent possible damage to the SHP1

digital interface. This is particularly an issue with portable computers (laptops, etc.) in which the power supplies

can generate large voltage spikes.

A suitable converter is the model USOPTL4 from B & B Electronics. One end has the USB connector to the PC the other end has

a connector with screw terminals for the instrument wires. This RS-485 converter is powered from the USB interface, so no

additional power adaptor is necessary.

Not connected

Not connected Situation up to serial number 144999

SHP1 connections to USB

.

Shield - ground connection

Analogue out +

Analogue out

Modbus® RS-485

Power 5 to 30 VDC

Power ground / RS-485 common

-

RS-485 / USB converter

Common

+ V

-

V

USB to PC

*

*Note Switches on the converter should be set for RS-485, 2-wire operation and Echo o.

Instruction Manual - SHP1 - Smart Pyrheliometer

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.

SHP1 connections to USB

Shield - ground connection

Not connected

Analogue out +

Analogue out

Modbus® RS-485

Modbus® common / Ground

Power 5 to 30 VDC

Power ground / RS-485 common

-

Situation from serial number 145000

RS-485 / USB converter

+ V

-

Common

V

*

*Note Switches on the converter should be set for RS-485, 2-wire operation and Echo o.

Connection to a RS-485 Network

The digital interface can be connected to a 2-wire RS-485 network as shown below.

Master

USB to PC

5 V

Pull up

LT LT

Balanced pair

Common

Pull down

Slave 1 Slave n

The interface needs also an external power to provide the voltage for the electronics. If the interface is the last device on the

network then a terminator consisting of a 120Ω or 150 Ω resistor has to be connected between terminal A/A'/- and B/B'/+. Never

place the line termination on the derivation cable. It is required to install the pull up and pull down resistors as shown in the

previous ﬁgure. The value of these resistors has to be within 650Ω and 850 Ω.

2.7 Analogue output connection

The SHP1-V (Volt version) has been factory set to an output of -200 to 2000 W/m². This applies only to the analogue output and

means that an output of 0 Volt corresponds to -200 W/m² (this will never be reached) and 1 Volt corresponds to 2000 W/m².

The digital output range can be modiﬁed with Modbus® commands. For the SHP1 the output range can be set to -200 to 4000 W/m²

for 0 to 1 Volt.

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The range has to start negative in order to show (small) negative readings also the analogue output itself cannot go negative. If

used in atmospheric conditions it is advised to keep the range as factory set.

The same applies for the SHP1-A (current version) that has been factory set to 0 to 1600 W/m² for 4 to 20 mA.

Here negative inputs will make the output go under 4 mA.

2.8 Calculations

2.8.1 Calculation 0 to 1 Volt version

The output is deﬁned from 0 to 1 Volt representing -200 to 2000 W/m².

E

The irradiance value (

of the analogue output. For calculation of the solar irradiance (global or reﬂected) the following formula must be applied:

formula 1

E

= Solar radiation [W/m²]

solar

V = Output of radiometer [Volt]

2.8.2 Calculation 4 to 20 mA version

The output is deﬁned from 4 to 20 mA representing 0 to 1600 W/m².

) can be simply calculated as shown below in formula 1. The formula assumes the factory default setting

solar

Negative outputs can cause the output to go slightly below 4 mA.

E

The irradiance value (

) can be simply calculated as shown below in formula 2. The formula assumes the factory default setting

solar

of the analogue output. For calculation of the solar irradiance (global or reﬂected) the following formula must be applied:

formula 2

E

= Solar radiation [W/m²]

solar

mA = Output of radiometer [mA]

2.8.3 Recommended cable types

Where cables need to be extended, or the customer prefers to provide their own cables, they should be suitable for outdoor used

and UV resistant.

Recommended types

RS-485 Ethernet CAT 5 shielded twisted pair (STP)

0 to 1 V Shielded 2-core signal cable

4 to 20 mA Shielded twisted pair control cable

Instruction Manual - SHP1 - Smart Pyrheliometer

16

3. Accessories

.

Below is a brief description of the available cables for the SHP1 pyrheliometer.

3.1 Cables

For connection, a standard 10 m cable (8 wires) is supplied with a straight 8 pin connector on one side and loose ends on the

other side. Optional longer cables are available or just a loose connector to make your own cable / connection.

25 m cable with connector

50 m cable with connector

100 m cable with connector

Loose connector without cable

Instruction Manual - SHP1 - Smart Pyrheliometer

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Instruction Manual - SHP1 - Smart Pyrheliometer

18

4. Software installation and conﬁguration

.

The SHP1 pyrheliometer is delivered with a software programme SmartSensorDemo.exe, This software is supplied on a CD-ROM.

The operating computer must be running on a 32-bit or 64-bit version of Windows™ XP or Windows™ 7. Insert the CD into the

CD/DVD ROM drive of the operating computer and follow the on-screen installation instructions.

Note Before installing the software it is advised to disconnect all Modbus® devices except for the device that you wish

to conﬁgure.

The program is for testing the instrument and setting parameters. Basic data logging and display of data on a PC is also possible.

The software can handle up to 10 SHP pyrheliometers at the same time connected to the same RS-485 to USB converter. This

software is not intended for continuous long-term measurement, which should be done through the RS-485 network controller.

The setup depends on the used RS-485 adapter. An interface that could be used is from B&B, model USOPTL4, that has galvanic

isolation between in- and output. One side holds the USB connector to the PC the other side has a connector for connection of

the wires. This RS-485 adapter is powered from its USB interface.

A power supply for the SHP1 is required, this can be from a 5 to 30 Volt. 12 VDC is advised.

For set-up the following connection to a PC can be used. It is advised to use a RS-485 interface with galvanic isolation between

PC and RS-485.

Care has to be taken when connecting to an ungrounded (portable) PC, especially when also the analogue output is used. The

mains ﬁlter inside the PC can generate huge voltage peaks that can exceed the limits of the SHP1 pyrheliometer.

Not connected

Not connected Situation up to serial number 144999

SHP1 connections to USB

Shield - ground connection

SHP1 connections to USB

Shield - ground connection

Analogue out +

Analogue out

Modbus® RS-485

Power 5 to 30 VDC

Power ground / RS-485 common

Not connected

Analogue out +

Analogue out

Modbus® RS-485

Modbus® common / Ground

Power 5 to 30 VDC

Power ground / RS-485 common

-

RS-485 / USB converter

Common

+ V

-

V

Situation from serial number 145000

RS-485 / USB converter

Common

+ V

-

V

USB to PC

Instruction Manual - SHP1 - Smart Pyrheliometer

19

4.1 Set up communication

When the Smart Sensor Demo program is opened there are 3 basic functions available; ‘Overview’, ‘Instrument’ and ‘Chart’.

With the ‘Overview’ tab active the communication parameters can be set as follows:

1. Select the communication port where the RS-485 converter is connected

2. Set the baud rate (19200 is the default setting)

3. Set the number of data bits and parity (8 bits with even parity is the default setting)

4. Set the sampling time (1 poll per second is the default setting)

5. Press the button ‘Discover the ﬁrst connected device’ (or press ‘Discover all connected devices’ if there is more than one

device connected)

4.2 Change the Modbus® address

With the ‘Overview’ tab active, you have the possibility to change the Modbus® address.

The default Modbus® address of a SHP1 pyrheliometer is 1. Before you can use the instrument in your network you must reconﬁgure

the address to a unique number. Each Modbus® device connected to a network must have a unique address.

1. Enter the old Modbus® address, this can be found with the button ‘Discover all connected devices’ (for example, enter 1).

2. Enter the new Modbus® address. This must be a unique number (for example, 24).

3. Press the ‘Change Modbus address’ button.

When the address has been changed the SHP1 pyrheliometer will restart itself.

Instruction Manual - SHP1 - Smart Pyrheliometer

20

4.3 Instrument data

With the ‘Instrument’ tab active the connected SHP1 pyrheliometer measurements are displayed. If multiple SHP1’s are connect-

ed the display will show alternating values from the dierent instruments. The large display showing the radiation can be

changed to (Body) Temperature.

The Body Temperature, SHP1 Power Supply Voltage and Time since power on are displayed in the lower part of the screen.

Instruction Manual - SHP1 - Smart Pyrheliometer

21

4.4 Chart

With the Chart’ tab active the SHP1 pyrheliometer measurements can be displayed as a graph.

It will show the last 250 measurements of irradiance (‘Radiation’ in W/m²) and/or the pyrheliometer housing temperature

(‘Body Temp’ in °C), as an accumulating graph. Vertical scaling can be set to maximum or automatic.

Instruction Manual - SHP1 - Smart Pyrheliometer

22

4.5 Data logging

Under File in Smart Sensor Demo the data logging can be set. The data format options are txt or csv. The csv log ﬁle has the

following format:

Together with the Modbus® address and the radiation data the body temperature and the power supply voltage to the SHP1

pyrheliometer are recorded.

At the bottom of the Smart Sensor Demo screen the message ‘The logﬁle C:\SHPdata\SHP-00.csv is open, press F12 to Append

Data.’ can be shown. With F12 a new data set can be linked to an existing ﬁle. Below is an example of a .txt ﬁle with linked data

from 2 days.

[11-1-2012 11:08:14]

DATE;TIME;SLAVE;SERIALNR;RADIANCE W/m²;TEMP C;POWER V

2012-01-11;11:08:15;001;00-0005; 708;30.7; 5.0;

2012-01-11;11:08:16;001;00-0005; 708;30.7; 5.0;

2012-01-11;11:08:17;001;00-0005; 708;30.7; 5.0;

[12-1-2012 9:20:17]

DATE;TIME;SLAVE;SERIALNR;RADIANCE W/m²;TEMP C;POWER V

2012-01-12;09:20:30;001;00-0005; 928;22.8; 5.0;

2012-01-12;09:20:37;001;00-0005; 929;22.8; 5.0;

2012-01-12;09:20:38;001;00-0005; 929;22.8; 5.0;

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5. Operation and measurement

.

SHP1 pyrheliometers only require suitable sources of power and radiation (light) to operate and make measurements. However,

it is necessary to connect them to some sort of readout or data storage device in order to save the measurements, there is no

internal data memory.

5.1 Data collection

An optimal setting for the data interval is to sample every second and store one minute averages. For setting up the combination

of pyrheliometer and data storage please refer to the manual of the data collection device.

Take care when using the analogue output to match the output range of the pyrheliometer closely to the input range of the data

collection device to maximise the available resolution and minimise noise.

This can be done by determining the maximum expected analogue output of the pyrheliometer in your application and taking

the minimum input range of your data collection device that can just handle that signal.

5.2 Key parts of SHP1 pyrheliometer

The detector of the SHP1 is based on passive thermal sensing element called a thermopile. Although the detector construction

diers between models, the fundamental working principle is applicable to all radiometers.

The thermopile responds to the total energy absorbed by a unique black surface coating developed by Kipp & Zonen, which is

non-spectrally selective. The thermopile warms up and the heat generated ﬂows through a thermal resistance to a heat-sink, the

pyrheliometer housing. The temperature dierence across the thermal resistance of the detector is converted into a small

voltage as a linear function of the absorbed irradiance.

A drying cartridge in the SHP1 pyrheliometer housing is ﬁlled with replaceable silica gel and prevents condensation on the inner

side of the window, which can cool down considerably on clear windless nights.

drying cartridge quartz window

connector

smart interface

detector aperture rings rain shield

alignment aids

housing

.

5.2.1 Window

The material of the pyrheliometer window deﬁnes the spectral measurement range of the instrument. In general 99% of the

solar radiation spectrum will be transmitted through the window and will be absorbed by the detector. The SHP1 window is

made of quartz.

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.

5.2.2 Detector

The thermopile sensing element is made up of a large number of thermocouple junction pairs connected electrically in series.

The absorption of thermal radiation by one of the thermocouple junctions, called the active (or ‘hot’) junction, increases its

temperature. The dierential temperature between the active junction and a reference (‘cold’) junction kept at a ﬁxed temper-

ature produces an electromotive force directly proportional to the dierential temperature created.

This is a thermoelectric eect. The sensitivity of a pyrheliometer depends on the individual physical properties of the thermopile

and its construction. The sensitivity of each thermopile is unique and therefore each radiometer has an individual calibration

factor. This sensitivity is stored in the SHP1 pyrheliometer conﬁguration memory.

The unique black coating on the top surface of the thermopile has a rough structure that eectively ‘traps’ more than 97% of the

incident radiation and heats up the hot junctions. The black-coated thermopile forms the detector, which has a spectral selectivity

of less than 2 %. This means that within the spectral range of the pyrheliometer, the absorption for each wavelength is equal to

within 2 %. The black absorptive coating is one of the most crucial and delicate parts of the pyrheliometer, Kipp & Zonen’s

provides the best possible stability over a long period of time under all meteorological circumstances.

5.2.3 Housing

The radiometer housing accommodates all the key parts of a SHP1 pyrheliometer. The anodized aluminium parts are lightweight

and give high mechanical and thermal stability to the instrument.

Due to ﬁne mechanical construction SHP1 pyrheliometers are virtually sealed and comply with international standard IP 67.

5.2.4 Drying cartridge

To keep the detector and electronics dry and to prevent condensation forming inside the window with temperature changes a

self-indicating silica gel desiccant is used to absorb humidity within the pyrheliometer. When fresh the desiccant has an orange

colour. After some time absorbing moisture the colour will change to clear (transparent). At this time the silica gel is not fully

saturated, but should be replaced with fresh orange desiccant as soon as possible. Replacement desiccant is available through

Kipp & Zonen representatives.

5.2.5 Cable and connector

For ease of installation and replacement during re-calibration of the radiometer, the SHP1 is provided with a waterproof cable

socket ﬁtted to the pyrheliometer housing. The matching waterproof plug is normally supplied pre-wired to a very high quality

yellow cable selected for low noise, very wide temperature range and UV resistance.

Cables come pre-wired to the connector plug in a range of lengths, 10 m is standard. 25 m, 50 m and 100 m lengths are also

available. The connector plug can also be supplied loose for the user to ﬁt to their own cable.

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6. Maintenance and re-calibration

.

SHP1 pyrheliometers are simple to maintain and do not require any special tools or training. There are no service items requiring

scheduled replacement, only the desiccant of the SHP1 requires changing when needed, and a periodical check of the alignment

at the sun.

6.1 Daily maintenance

Once installed, the radiometer needs little maintenance. The front window must be cleaned and inspected regularly.

The frequency of cleaning is highly dependent upon the local weather and environmental conditions, such as dust, airborne

pollutants or salt spray in marine environments. Ideally, the window of the pyrheliometer should be cleaned every morning

before sunrise.

Note Clean the window using pure alcohol or distilled water and a lint-free cloth. Ensure that no smears or deposits are

left on the window.

6.2 Monthly maintenance

Check the desiccant in the drying cartridge. This is a self-indicating silica-gel. When it requires replacement the colour changes

from orange to clear.

To replace the desiccant unscrew the cartridge from the radiometer housing, if it is tight a 16 mm or 5/8" open-ended wrench /

spanner can be used to loosen it. Remove the cap from the end of the cartridge and safely dispose of the used silica-gel. Reﬁll

with fresh desiccant, and reﬁt the end cap to the cartridge. Make sure that the o-ring seal and its seat in the housing are clean,

grease with Vaseline if it is dry.

Note Screw in the drying cartridge hand-tight only, to avoid distorting the o-ring seal.

Desiccant reﬁll packs are available from Kipp & Zonen. One pack is sucient for one complete reﬁll.

6.3 Yearly maintenance

Check all the electrical connections. Unscrew the plugs, clean if necessary and then reconnect.

Check cables for damage caused by accident or by rodents.

Check the instrument mountings and any supports are secure.

6.4 Calibration

An ideal radiometer gives an output that is proportional to the absolute irradiance level. This relationship can be expressed as

a constant ratio called ‘sensitivity’. SHP1 pyrheliometers are very stable instruments, but they do change very slightly with time.

This is largely due to exposure of the black detector coating to UV solar radiation. Re-calibration is recommended every two

years. Normally this is carried out at the Kipp & Zonen factory or at an authorised calibration facility.

.

6.4.1 Calibration principle

At the Kipp & Zonen factory pyrheliometers are calibrated, or re-calibrated, in our laboratory according to ISO 9059:1990 ‘Solar

energy - Calibration of ﬁeld pyrheliometers by comparison to a reference pyrheliometer’.

Kipp & Zonen uses a Xenon lamp with precise voltage stabilisation. The irradiance at the radiometers is approximately 800 W/m².

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The reference pyrheliometers are regularly calibrated outdoors at the World Radiation Centre (WRC) in Davos, Switzerland. The

spectral content of the laboratory calibration lamp diers from the outdoor solar spectrum at the World Radiation Centre. However,

this has no consequences for the transfer of calibration, because the reference and test radiometers have the same characteristics.

The sensitivity of the test pyrheliometer is calculated by comparison to the reference pyrheliometer readings and the calibration

certiﬁcate is produced. At Kipp & Zonen the complete process is automated under computer control, including programming the

SHP1 pyrheliometer with the correct calibration factors and default output range settings.

6.4.2 Calibration traceability to the WRR

Our reference pyrheliometers are calibrated at the World Radiation Centre (WRC) in Davos, Switzerland by comparison to the

World Radiometric Reference (WRR). They are also fully characterized for linearity, temperature dependence and directional

response to enable transfer of the sensitivity under the measurement conditions in Davos to our calibration laboratory conditions.

Kipp & Zonen keeps at least two reference instruments for each pyrheliometer model. These reference instruments are sent

alternate years to the WRC for calibration, so that production and calibration in Delft can carry on without interruption.

Kipp & Zonen calibration certiﬁcates include an overview of the calibration method, details of the reference pyrheliometer used,

traceability to the WRR, and the uncertainty in the full calibration chain from the WRR to the pyrheliometer being calibrated.

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7. Speciﬁcations

.

Kipp & Zonen reserves the right to make changes to speciﬁcations and other product documentation without prior notice.

7.1 Optical and electrical

Speciﬁcations SHP1

ISO 9060:1990 CLASSIFICATION Response time (63 %) < 0.7 s Response time Zero offsets, temperature change (5 K/hr) < 1 W/m² Non-stability (change/year) Non-linearity (0 to 1000 W/m²) Temperature dependence of sensitivity

Full viewing angle Slope angle 1 ° Maximum irradiance 4000 W/m² (damage may occur above this level) Operating temperature Humidity Spectral range Required sun tracker accuracy Weight 0.9 kg

(95 %)

(relative humidity) 0 to 100 % rH

(50 % points) 200 to 4000 nm

Other speciﬁcations

Analogue output

Analogue output range

Digital output Digital output maximum range -400 to 4000 W/m² Digital communication protocol Modbus® Operating temperature Ingress Protection Supply voltage Power consumption

Expected daily uncertainty < 1 % Documentation Recommended applications

(1)

The analogue output range of SHP1 can be rescaled by the user to a maximum of -200 to 4000 W/m² SHP1 pyrheliometer has a standard cable length of 10 m. Optional cable lengths 25 m, 50 m and 100 m

Note: The performance speciﬁcations quoted are worst-case and/or maximum values

(IP) 67

(at 12 VDC)

First Class

< 2 s

< 0.5 % < 0.2 % < 1 %

(-40 °C to +70 °C)

< 0.5 %

(-30 °C to +60 °C)

(±0.2)

5 °

(±0.2)

-40 °C to +80 °C

< 0.5° from ideal

-V version: 0 to 1 V

-A version: 4 to 20 mA

-V version: -200 to 2000 W/m²

-A version: 0 to 1600 W/m² 2-wire RS-485

-40 °C to +80 °C

5 to 30 VDC

-V version: 55 mW

-A version: 100 mW

Calibration certiﬁcate traceable to WRR, multi-language instruction sheet, manual and software on CD-ROM High performance direct radiation monitoring for meteorological stations or concentrated solar energy applications

(1)

7.2 Dimensions

195.6 mm

Ø38 mm

322 mm

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8. Trouble shooting

.

There are no user-serviceable parts within the SHP1 pyrheliometer and it must not be opened without the agreement and instruction

of Kipp & Zonen.

8.1 Output signal not present or incorrect

The following contains a procedure for checking the instrument in case it appears that it does not function correctly:

1. Check the SHP1 pyrheliometer cable wires are properly connected to the readout equipment.

2. Check the power supply (12 VDC recommended).

3. Check that the instrument has a unique Modbus® address.

4. Compare the digital and analogue outputs to see if the problem is in one output only.

5. Check the instrument location. Are there any obstructions that cast a shadow on the instrument by blocking the direct sun

during some part of the day?

6. Check the window, it should be clear and clean. If condensation is deposited on the inside, please change the desiccant. If too

much water is deposited internally the drying cartridge should be removed and the instrument warmed to dry it and then

replace with new desiccant. It may take several days for the sensitivity to fully recover to the original value.

7. For analogue outputs check the data logger or integrator input oset such that a signal of 0 Volt or 4 mA (as appropriate)

gives a ‘zero’ reading.

8. If water, frost or ice is deposited on the window, clean it. Probably water droplets will evaporate in less than one hour under

sunlight.

Any malfunction or visible damage should be reported to your Kipp & Zonen representative, who will suggest the appropriate action.

8.2 Frequently Asked Questions

The most frequently asked questions are listed below. For an update or further information refer to our website at www.kippzonen.com

Q: Is it possible that direct radiation is higher than global radiation?

A: Yes, this is possible because the relation is:

Global = Diuse + (Direct x cos α); α is the solar zenith angle

So with low solar elevation (small cos α) the contribution of the direct radiation to the total (global) is relatively small.

Q: When is the pyrheliometer properly aligned?

A: When the second alignment aid on top of the SHP1 is in the light spot falling through the ﬁrst alignment aid the pyrheliometer

is properly aligned. As long as the second alignment aid is in the light spot, the SHP1 is within speciﬁcations.

Q: Is the pyrheliometer calibration aﬀected by the length of the signal cable?

A: With longer cable lengths the impedance increases, however it does not aect the radiometer sensitivity for the following

reason. For the SHP1-V the impedance of the voltage measurement device is at least 1000 times more than the impedance of the

pyrheliometer plus cable. Therefore the current that goes through the readout cable is negligible and won’t generate an oset.

For the SHP1-A current versions the cable length is limited by the power supply voltage and voltage drop over the cable. However

the low cable impedance (80 Ω/km) and normally high impedance of the read-out unit / logger is normally no limitation.

The digital RS-485 output can operate over cable lengths up to 1000 m, depending on the baud-rate used.

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9. Customer support

.

If you require any support for your Kipp & Zonen product please contact your local representative in the ﬁrst instance. The information can be found in the ‘Contact’ section (home tab) of our website at www.kippzonen.com

Alternatively, you can contact us directly at www.kippzonen.com/support

Please include the following information:

• Instrument model

• Instrument serial number

• Details of the fault or problem

• Examples of data ﬁles

• Readout device, data acquisition system and operating system

• Interfaces and power supplies

• History of any previous repairs or modiﬁcations

• Pictures of the installation

• Overview of the local environment conditions

Kipp & Zonen guarantees that your information will not be shared with other organisations.

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10. Keyword index

.

Term Explanation

Albedo The portion of incoming radiation which is reﬂected by a surface

Azimuth angle Angle in horizontal direction (0 to 360 °) normally referred to North

Angle of incidence Incident angle from zenith (0° is vertical, 90° is horizontal)

Cosine response Radiometer directional response according to the cosine law

Diuse horizontal irradiance Solar radiation, scattered by water vapour, dust and other particles as it passes through

the atmosphere falling on a horizontal surface (DHI)

Direct normal irradiance Radiation that has travelled in a straight path from the sun falling on a surface normal to

the beam (DNI)

Global horizontal irradiance Total irradiance falling on a horizontal surface (GHI)

Global = Diuse + (Direct x cos α); α is the solar zenith angle

Irradiance Radiant ﬂux density (W/m²)

Long-wave radiation Radiation with wavelengths from 4 m to more than 40 m

Pyranometer Radiometer for measuring short-wave global radiation

Pyrgeometer Radiometer for measuring long-wave radiation

Pyrheliometer Radiometer for measuring direct short-wave radiation

Short-wave radiation Radiation with wavelengths from approximately 300 nm to 4000 nm (4 m)

Thermopile Thermal detector made up of many thermocouple junctions

WMO World Meteorological Organisation, Geneva, Switzerland

WRC World Radiation Centre, Davos, Switzerland

WRR World Radiometric Reference (standard radiation scale) at WRC

WSG World Standard Group of radiometer at WRC

Zenith angle Angle from zenith (0 ° is vertical)

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Appendices

A. Modbus®

A.1 Modbus® commands

The commands are all according to the Modbus® RTU protocols described in the document: ‘Modbus® over serial line V1.02’ and

‘Modbus® application protocol V1.1b’ available from the Modbus® organization (www.modbus.org). The commands can be tested

using software tools, such as the program ‘Modbus® Poll’ from www.modbustools.com.

The following commands are implemented:

Function Sub function Description

0x01 N/A Read Coils

0x02 N/A Read Discrete Inputs

0x03 N/A Read Holding Registers

0x04 N/A Read Input Register

0x05 N/A Write Single Coil

0x06 N/A Write Holding Register

0x10 N/A Write multiple Registers

The SHP1 does not make a dierence between a ‘coil’ and a discrete input. The only dierence is that a discrete input is read only.

The SHP1 does not make a dierence between a holding register and an input register. The only dierence is that an input

register is read only.

A.2 Input registers

Input registers are read only

Real-time Processed Data

Register Parameter R/W Type Mode Description

0 IO_DEVICE_TYPE R U16 All Device type of the sensor

1 IO_DATAMODEL_VERSION R U16 All Version of the object data model 100=this version

2 IO_OPERATIONAL_MODE R U16 All Operational mode: Normal, Service, Calibration and so on

3 IO_STATUS_FLAGS R U16 All Device status ﬂags

4 IO_SCALE_FACTOR R S16 All Range and scale factor sensor data

5 IO_SENSOR1_DATA R S16 N,S Temperature compensated data sensor 1 in W/m²

6 IO_RAW_SENSOR1_DATA R S16 N,S Sensor data sensor 1 in W/m²

7 IO_STDEV_SENSOR1 R S16 N,S Standard deviation sensor 1 in 0.1 W/m²

8 IO_BODY_TEMPERATURE R S16 N,S Body temperature in 0.1 °C

9 IO_EXT_POWER_SENSOR R S16 N,S External power voltage in 0.1 V

10 to 15 FACTORY USE ONLY

16 IO_DAC_OUTPUT_VOLTAGE R U16 N,S DAC output voltage (actual voltage)

17 IO_SELECTED_DAC_INPUT R U16 N,S DAC selected input data

(1)

The scale factor deﬁnes the format and number of decimal places

(1)

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Real-time Data A/D Counts

Register Parameter R/W Type Mode Description

18 IO_ADC1_COUNTS R S32 All Input voltage sensor 1 in 0.01 V

19 (R18=MSB, R19=LSB)

20 IO_ADC2_COUNTS R S32 All Not supported, always 0

21

22 IO_ADC3_COUNTS R S32 All Input voltage body temperature sensor in 0.01 V

23 (R22=MSB, R23=LSB )

24 IO_ADC4_COUNTS R S32 All Input voltage power sensor in 0.01 V

25 (R24=MSB, R25=LSB)

Error reports

Register Parameter R/W

26 IO_ERROR_CODE R U16 All Most recent/ actual error code

27 IO_PROTOCOL_ERROR R U16 All Protocol error/communication error

28 IO_ERROR_COUNT_PRIO1 R U16 All Error code priority 1

29 IO_ERROR_COUNT_PRIO2 R U16 All Error count priority 2

30 IO_RESTART_COUNT R U16 All Number of controlled restarts

31 IO_FALSE_START_COUNT R U16 All Number of uncontrolled restarts

32 IO_SENSOR_ON_TIME R U16 All On time in seconds (MSB word)

33 IO_SENSOR_ON_TIMEL R U16 All On time in seconds (LSB word)

41 IO_BATCH_NUMBER R U16 All Production batch number

42 IO_SERIAL_NUMBER R U16 All Serial number

43 IO_SOFTWARE_VERSION R U16 All Software version

44 IO_HARDWARE_VERSION R U16 All Hardware version

45 IO_NODE_ID R U16 All (MODBUS®/SMA) device address RS-485

(2)

Writing any value to input registers 26-33 will reset the contents of the registers

(2)

Type Mode Description

Legend

Register Modbus® register Modbus® register 0 is the ﬁrst register. Parameter Name Name of the register R/W Read write R Read only R/W Read/write Type Type and size U16 16 bit unsigned integer

S16 16 bit signed integer S32 32 bit signed integer (MSB ﬁrst, LSB last) Mode Operation mode N available in normal mode S available in service mode C available in calibration mode (not for users) F available in factory mode (not for users) All available in all modes

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.

A.3 Holding registers

Device Control

Register Parameter R/W Type Mode Description

34 IO_DEF_SCALE_FACTOR R/W S16 All Default scale factor

35 to 40 Factory use only

A.4 Read input register

Many of the registers and controls are for remote diagnostics. In this chapter only the most interesting registers and controls

are described.

Register 0 IO_DEVICE_TYPE

The device typed deﬁnes which device is connected. The default values are:

Instrument type Sensor type Device type

SMP3-V 1 601

SMP3-A 1 602

SMP11-V 3 603

SMP11-A 3 604

SHP1-V 6 613

SHP1-A 6 614

This register can be used to check the type of the connected device.

Register 1 IO_DATAMODEL_VERSION

The data-model describes the functions supported by the smart sensor. This document is valid for data-model version: ‘100’ and

‘101’. A dierent implementation of the Modbus® protocol (with new features) could result in a dierent data model ‘that is’ or

‘that is not’ compatible with the older version.

The value of this register must be ‘100’ or ‘101’. If you receive another value then you should read an updated version of this

document and check the dierences.

Register 2 IO_OPERATIONAL_MODE

The operation mode deﬁnes the state of the smart sensor. The operational modes are 1 = Normal Mode, 2 = Service Mode,

3 = Calibration Mode, 4 = Factory Mode and 5 = Error mode. The standby mode (mode 0) is not supported.

After power on the operation mode (1) is set. When the IO_CLEAR_ERROR is set then the smart sensor always returns to the

normal mode. When the Error mode (5) is set, then there is a fatal error.

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.

Register 3 IO_STATUS_FLAGS

This register deﬁnes the status of the smart sensor and the validity of the data. Each bit has a special meaning. Bit 0 is the ﬁrst

(least signiﬁcant) bit.

Bit 0 Quality of the signal see IO_VOID_DATA_FLAG

Bit 1 Overﬂow see IO_OVERFLOW_ERROR

Bit 2 Underﬂow see IO_UNDERFLOW_ERROR

Bit 3 Error ﬂag see IO_ERROR_FLAG

Bit 4 ADC Error see IO_ADC_ERROR

Bit 5 DAC Error see IO_DAC_ERROR

Bit 6 Calibration Error see IO_CALIBRATION_ERROR

Bit 7 Update EEPROM error see IO_UPDATE_FAILED

Register 4 IO_SCALE_FACTOR

The scale factor deﬁnes the number of fractional digits, the range and the position of the decimal point for the following registers: IO_SENSOR1_DATA, IO_SENSOR2_DATA, IO_RAW_SENSOR1_DATA and IO_RAW_SENSOR2_DATA. The scale factor is read

only. The default value of the scale factor is set during calibration mode or it can be changed during operation (see register IO_DEF_SCALE_FACTOR and coil IO_AUTO_RANGE).

If the register IO_SCALE_FACTOR is not set to 0 then you must multiply or divide the data of register (X), whereas X is one of the

above mentioned registers.

Scale factor = 2 (ﬂoating point) result = (integer) register (X) / 100.0

Scale factor = 1 (ﬂoating point) result = (integer) register(X) / 10.0

Scale factor = 0 (ﬂoating point) result = (integer) register(X)

Scale factor = -1 (ﬂoating point) result = (integer) register(X) * 10.0

The default value of register IO_SCALE_FACTOR is 0. However, this value can be set to a dierent value if the coil IO_AU-

TO_RANGE is set or a dierent value is written to the register IO_DEF_SCALE_FACTOR (set default scale factor).

Register 5 IO_SENSOR1_DATA

This register holds the actual data (solar radiation) measured by the sensor. The solar radiation is measured in W/m².

If the register IO_SCALE_FACTOR is not set to 0 then you must multiply or divide the data as described under register 4.

The raw data from the sensor is calibrated, linearized; temperature compensated and ﬁltered using 2 dierent kinds of ﬁlters (See IO_FAST_RESPONSE and IO_TRACKING_FILTER).

Register 6 IO_RAW_SENSOR1_DATA

The raw sensor data is calibrated but not linearized and temperature compensated. If the register IO_SCALE_FACTOR is not set to 0 then you must multiply or divide the data as described under register 4, IO_SCALE_FACTOR.

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.

Register 7 IO_STDEV_SENSOR1

This register is used to calculate the standard deviation over the signal. When the register is read the data is sent to the computer

and at the same time a new calculation is started. The next time register 7 is read the standard deviation over the last period is

sent to the computer and a new calculation is started. If the poll frequency is quite high (for example 1 poll per second) then the

standard deviation will be zero or almost zero, but if the poll frequency is very low then the standard deviation can be quite high,

indicating that the data in register 5 or 6 changed dramatically since the last poll. The standard deviation is measured in 0.1 W/m².

To convert the data to a ﬂoating point, make the following calculation:

(ﬂoating point) result = (integer) register (IO_STDEV_SENSOR1) / 10.0

Register 8 IO_BODY_TEMPERATURE

The body temperature sensor measures the temperature of the body in 0.1°C.

The convert the data to a ﬂoating point number, make the following calculation:

(ﬂoating point) result = (integer) register (IO_BODY_TEMPERATURE) / 10.0

Register 9 IO_EXT_POWER_SENSOR

The Ext power sensor measured the external voltage applied to the sensor in 0.1 Volt.

The convert the data to a ﬂoating point number, make the following calculation:

(ﬂoating point) result = (integer) register (IO_EXT_POWER_SENSOR) / 10.0

Example

Read registers: ‘operational mode to external power’ from Modbus® device with address 1.

Tx transmitted data to the smart sensor

Rx received data from the smart sensor

SendModbusRequest (0x04, 1, IO_OPERATIONAL_MODE, 8);

Tx 01 04 00 02 00 08 50 0C

Rx 01 04 10 00 01 00 00 00 00 03 E5 03 E5 00 00 00 F8 00 EA 66 12

Explanation of the received bytes:

01 = Modbus® address

04 = read input registers

10 = number of received data bytes

00 01 = operational mode (mode 1)

00 00 = status ﬂags (none)

00 00 = scale factor = 0 = 1x

03 E5 = 997 decimal = sensor 1 data in W/m²

03 E5 = 997 decimal = raw sensor 1 data in W/m²

00 00 = 0 = standard deviation sensor 1

00 F8 = 248 = 24.8 °C.

00 EA = 234 = 23.4 Volt

66 12 = Modbus® checksum (CRC16)

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.

A.5 Discrete inputs

A discrete input can be true or false. A discrete input is read only; a coil can be read or written.

Status indicators

Input Parameter R/W Def. Mode Description

0 IO_FALSE R 0 All Always false (for testing only)

1 IO_TRUE R 1 All Always true (for testing only)

2 IO_VOID_DATA_FLAG R * All Void signal, 1=unstable signal, temperature too low or too high

3 IO_OVERFLOW_ERROR R * All Overﬂow, signal out of range

4 IO_UNDEFLOW_ERROR R * All Underﬂow signal out of range

5 IO_ERROR_FLAG R * All General hardware error (set if one of the H/W error ﬂags is set)

6 IO_ADC_ERROR R * All Hardware error A/D converter

7 IO_DAC_ERROR R * All Hardware error D/A converter

8 IO_CALIBRATION_ERROR R * All Calibration checksum error

9 IO_UPDATE_FAILED R * All Update calibration parameters failed

Legend

Input Discrete input Modbus® discrete input 0 is the ﬁrst discrete input Coil Modbus® Coil A coil can be read or written. Parameter Name Name of the register R/W Read write R Read only R/W Read/write Def Default value default value at power on (0, 1or *) * = undeﬁned Mode operation mode N available in normal mode

S available in service mode C available in calibration mode (not for users) F available in factory mode (not for users) All available in all modes

Inputs can be read in all modes but some coils can’t be written in normal mode or service mode.

A.6 Coils

Device control

Coil Parameter R/W Def. Mode Description

10 IO_CLEAR_ERROR R/W 0 All Select normal operation and clear error (1=clear error)

11 to 17 FACTORY USE ONLY

18 IO_RESTART_MODBUS R/W 0 All Restart the device with modbus® protocol

19 FACTORY USE ONLY

20 IO_ROUNDOFF R/W 1 S,N Enable rounding of sensor data

21 IO_AUTO_RANGE R/W 0 S,N Enable auto range mode (0=no auto range)

22 IO_FASTRESPONSE R/W 0 S,N Enable fast response ﬁlter (0=no ﬁlter)

23 IO_TRACKING_FILTER R/W 1 S,N Enable tracking ﬁlter (0=no ﬁlter)

Note The default values of the device options are stored in non-volatile memory. The default values can be overruled during

operation. However, at power-on the default values are restored and the smart sensor will start up with the default

values stored in the non-volatile memory.

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.

ADC CONTROL

Coil Parameter R/W Def. Mode Description

24 to 34 Factory use only

A.7 Read write holding registers

Register 34 IO_DEF_SCALE_FACTOR

The default scale factor is set in the factory mode or service mode and is stored in non-volatile memory. The default scale factor

stored in non-volatile memory is always set after a power-on. However it is possible to change the default setting during opera-

tion by writing a value to the register 34.

Note This value is not stored in non-volatile memory and is overwritten with the default value at power on.

The following values are valid:

Scale factor = 2

Scale factor = 1

Scale factor = 0

Scale factor = -1 Scale factor 0 is the default value. See also input register 4 IO_SCALE_FACTOR.

A.8 Read discrete inputs

Discrete input 0 IO_FALSE This discrete input is always false Discrete input 1 IO_TRUE This discrete input is always true Discrete input 2 IO_VOID_DATA_FLAG

The void data ﬂag is raised when the data in register IO_SENSOR1_DATA or IO_RAW_SENSOR1_DATA is not valid, because the

body temperature of the sensor is too low or too high, when there is an internal overﬂow condition, because a calculation is out

of range or a division by zero occurred, the reference voltage of the ADC is not stable or the digital ﬁlter is not stable. When the IO_VOID_DATA_FLAG is set, bit 0 in the IO_STATUS_FLAGS is also set.

The IO_VOID_DATA_FLAG and bit 0 of the IO_STATUS_FLAGS are cleared when the IO_VOID_DATA_FLAG is read by the computer.

Discrete input 3 IO_OVERFLOW_ERROR

This discrete input is raised when an out of range condition occurs and the sensor data (see IO_SENSOR1_DATA) is above the

maximum value speciﬁed by the calibration program or above 29,999. The typical maximum value is 4000 W/m².

When the IO_OVERFLOW_ERROR is set, bit 1 in the IO_STATUS_FLAGS is also set.

The IO_OVERFLOW_ERROR and bit 1 of the IO_STATUS_FLAGS are cleared when the IO_OVERFLOW_ERROR is read by the computer.

Discrete input 4 IO_UNDERFLOW_ERROR

This discrete input is raised when an underﬂow condition occurs and the sensor data (see IO_SENSOR1_DATA) is below the

minimum value speciﬁed by the calibration program or below -29,999. The typical minimum value is -400 W/m².

When the IO_UNDERFLOW_ERROR is set, bit 2 in the IO_STATUS_FLAGS is also set.

The IO_UNDERFLOW_ERROR and bit 2 of the IO_STATUS_FLAGS are cleared when the IO_UNDERFLOW_ERROR is read by the

computer.

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Discrete input 5 IO_ERROR_FLAG

The error ﬂag is raised when there is a (fatal or correctable) hardware error or software error such as: ADC error, DAC error, calibration error or when the update of the calibration data failed. When the IO_ERROR_FLAG is raised the error code is copied to the register IO_ERROR_CODE (see register 26).

The error ﬂag is cleared when a true condition is written to the coil: ‘IO_CLEAR_ERROR’. This has no eect when the error is fatal

or not resolvable such as a calibration error.

The error ﬂag is always set after a power up, this is to indicate the power went o, or a restart occurred. The computer should raise the IO_CLEAR_ERROR in order to reset the error ﬂag.

Discrete input 6 IO_ADC_ERROR

This ﬂag is raised when the A/D converter responsible for the conversion of the analogue signals to digital signals detected a

failure (hard or software).

The ADC error ﬂag is cleared when a true condition is written to the coil: ‘IO_CLEAR_ERROR’ and the error produced by the ADC,

is not fatal.

Discrete input 7 IO_DAC_ERROR

This ﬂag is raised when the D/A converter responsible for the conversion of the digital signal to the analogue output signal

detected a failure (hard or software).

The DAC error ﬂag is cleared when a true condition is written to the coil: ‘IO_CLEAR_ERROR’ and the error produced by the DAC,

is not fatal.

Discrete input 8 IO_CALIBRATION_ERROR

The calibration error ﬂag is raised when the sensor was not calibrated or a checksum error was detected in the calibration data.

This ﬂag can’t be cleared unless the sensor is sent back to the manufacturer or dealer for a re-calibration.

Discrete input 9 IO_UPDATE_FAILED

The update failed is raised when data is written to the non-volatile memory and the update failed. This can happen in calibration

mode when calibration data in written to non-volatile memory or in the service mode when device options are written to the

non-volatile memory.

If this error is set you should retry the last update action. If the error does not disappear then there could be a hardware

problem with the non-volatile memory (EEPROM).

A.9 Read write discrete coils

Coil 10 IO_CLEAR_ERROR

Setting this coil will clear the error only when the error is a non-fatal error. Reading this coil will always return a 0. The coil IO_CLEAR_ERROR can be used to select the normal mode (see IO_OPERATIONAL_MODE).

The smart sensors will always start-up in the normal mode. Note Use IO_CLEAR_ERROR to return to the normal mode.

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Coil 20 IO_ROUNDOFF

Setting this coil enables rounding of the data presented in IO_SENSOR1_DATA and IO_RAW_SENSOR1_DATA.

If not set then the customer should round o the received data before processing the data.

The default value after power on is ON.

If IO_ROUNDOFF is cleared, then the sensor is not calibrated and could produce more digits, than there are signiﬁcant digits.

Coil 21 IO_AUTO_RANGE

Setting this coil enables the auto-range feature. The auto-range feature increases the number of digits for small signals

The default value after power on is OFF.

If IO_AUTO_RANGE is set then the sensor is not calibrated and could produce more digits, than there are signiﬁcant digits.

Coil 22 IO_FASTRESPONSE

Setting this coil enables the fast response ﬁlter. This ﬁlter increases the step response of the sensor. Disabling the fast response

give the SHP1 pyrheliometers the same response time as the CMP equivalents.

The default value after power on is ON.

Coil 23 IO_TRACKING_FILTER

Setting to this coil enables the tracking ﬁlter. The tracking ﬁlter reduces the noise of the signal. However, when the ﬁlter is on,

the step response on a sudden signal change is decreased. The smart sensor uses variable ﬁlter constants to minimize the eect

on the step response.

The default value after power on is OFF.

A.10 Requesting serial number

Register 41 IO_BATCH_NUMBER

The batch number deﬁnes the production year of the smart sensor, 11 = 2011, 12=2012 etc.

Register 42 IO_SERIAL_NUMBER

Register 42 deﬁnes the 4 digits serial number of the smart sensor. Only the combination of the batch number and serial number

is unique.

A.11 Simple demonstration program

The simple ‘C’ program below will show how to read the sensor data and how to deal with errors. The program will read the

registers: ‘operational mode, status ﬂags, scale factor, and sensor data’ from Modbus® device with address 2 into registers

uOperationMode, uStatusFlags, iScaleFactor and iSensorData. Then the program will check the operation mode (must be ‘normal’) and if there are no errors ﬂags set in iStatusFlags. If there is an error then set the IO_ERROR_FLAG.

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.

UInt16 uOperationalMode = 0;

UInt16 uStatusFlags = 0;

Int16 iScaleFactor = 0;

Int16 iSensorData = 0;

ﬂoat fSensorData = 0;

int main (void)

{

while (true)

{

// Send Modbus® request 0x04 Read input registers to slave 2

// Get modus data will wait for the answer and copies the data to registers

// uOperationalMode, uStatusFlags, iScaleFactor and iSensorData

SendModbusRequest (0x04, 2, IO_OPERATIONAL_MODE, 4);

WaitModbusReply ();

GetModbusData ();

If (uOperationalMode != 1)

{

// Send Modbus® request 0x05 write single coil to slave 2

SendModbusRequest (0x05, 2, IO_CLEAR_ERRROR, true);

WaitModbusReply ();

}

else if (uStatusFlags != 0)

{

SendModbusRequest (0x05, 2, IO_CLEAR_ERRROR, true);

WaitModbusReply ();

}

switch (iScaleFactor)

{

case 2: fSensorData = (ﬂoat)(iSensorData) / 100.0;

case 1: fSensorData = (ﬂoat)(iSensorData) / 10.0;

case 0: fSensorData = (ﬂoat)(iSensorData);

case -1: fSensorData = (ﬂoat)(iSensorData) * 10.0;

default: fSensorData = 0.0;

}

// wait 1 second

Delay (1000);

}

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46

B. Pyrheliometer physical properties

B.1 Spectral range

The spectrum of the solar radiation reaching the Earth’s surface is in the wavelength range between 280 nm and 4000 nm,

extending from ultraviolet (UV) to the far infrared (FIR). Due to the excellent physical properties of the quartz window and black

absorber paint, Kipp & Zonen SHP1 pyrheliometers are equally sensitive in a wide spectral range. 99% of the total energy will

be absorbed by the thermal detector.

1.0

0.5

Response [arbitrary units]

0

Wavelength [nm]

B.2 Sensitivity

For the SHP1 pyrheliometers the physical sensitivities are converted to a digital output that is identical for all sensors. The

SHP1-V has an analogue output of 0 to 1 Volt for -200 to 2000 W/m². The SHP1-A output is 4 to 20 mA for 0 to 1600 W/m².

3002001000

400 500 1000 2000 3000 4000

Solar radiation spectrum at sea level

Spectral response of SHP1 pyrheliometer

B.3 Response time

Any measuring device requires a certain time to react to a change in the parameter being measured. The radiometer requires time

to respond to changes in the incident radiation. The response time is normally quoted as the time for the output to reach 95%

(sometimes 1/e, 63%) of the ﬁnal value following a step-change in irradiance. It is determined by the physical properties of the

thermopile and the radiometer construction. SHP1 pyrheliometer is set to digitally accelerate the physical response.

B.4 Non-linearity

The non-linearity of a pyrheliometer is the percentage deviation in the sensitivity over an irradiance range from 0 to 1000 W/m²

compared to the sensitivity calibration irradiance of 500 W/m². The non-linear eect is due to convective and radiative heat

losses at the black absorber surface which make the conditional thermal equilibrium of the radiometer non-linear.

B.5 Tempearture dependence

The sensitivity change of the radiometer with ambient temperature change is related to the thermo-dynamics of the radiometer

construction. The temperature dependence is given as percentage deviation with respect to the calibrated sensitivity at +20°C.

The SHP1 pyrheliometer has an integrated temperature sensor and use a fourth-order polynomial function to actively correct for

temperature errors over a -40 °C to +70 °C range.

B.6 Operating temperature

The operating temperature range of the radiometer is determined by the physical properties of the individual parts. Within the speciﬁed

temperature range Kipp & Zonen radiometers can be operated safely. Outside this temperature range special precautions should be

taken to prevent any physical damage or performance loss of the radiometer. Please contact your Kipp & Zonen representative for

further information regarding operation in unusually harsh temperature conditions.

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B.7 Field of view

The beam of light that reaches the detector is limited by the ﬁeld and aperture stops. The slope and viewing angles are determined

by R, r and d.

ﬁeld stop

detector surface

aperture stop

pointing margin

angle of the sun = 0.5°

r

aperture stop

R

viewing angle = 5°

α

= half viewing angle = 2.5°

o

α

= slope angle = 1°

p

d

ﬁeld stop

For the SHP1 the full viewing angle is 5 °, the slope angle is 1 °. The sun, as seen from the detector, occupies a solid angle of 0.5 °.

A 100 % response can be expected only if the sun is entirely within the slope angle. This is the case when tracking accuracy is

better than slope angle minus half the solar angle.

Concluding, the tracking accuracy of the sun tracker should be better than the 0.75 ° pointing margin of the pyrheliometer, and

therefore within 0.5 ° of ideal.

.

B.8 Maximum irradiance

The maximum irradiance is deﬁned as the total irradiance level beyond which the output is no longer linear and out of speciﬁcations.

The analogue output for the SHP1 is set to 2000 W/m², which is sucient under normal atmospheric conditions. For special applications

the SHP1 can be set higher, up to 4000 W/².

B.9 Non-stability

This is the percentage change in sensitivity over a period of one year. This eect is mostly due to degradation by UV radiation

of the black absorber coating on the thermopile surface.

B.10 Spectral selectivity

Spectral selectivity is the variation of the window transmittance and absorption coecient of the black detector coating with

wavelength and is commonly speciﬁed as % of the mean value.

B.11 Environmental

The SHP1 is intended for outdoor use under all expected weather conditions. The radiometer complies with IP 67 and their solid

mechanical construction is suitable to be used under all environmental conditions within the speciﬁed ranges.

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B.12 Uncertainty

The measurement uncertainty of a pyrheliometer can be described as the maximum expected hourly or daily uncertainty with

respect to the ‘absolute truth’. The conﬁdence level is 95 %, which means that 95 % of the data-points lie within the given

uncertainty interval representing the absolute value. Kipp & Zonen empirically determine uncertainty ﬁgures based on many

years of ﬁeld measurements for typical operating conditions.

When a pyrheliometer is in operation, the performance of it is correlated to a number of parameters, such as temperature, level

of irradiance, etc. If the conditions dier signiﬁcantly from calibration conditions, uncertainty in the calculated irradiances must

be expected.

C. Pyrheliometer classiﬁcation to ISO 9060:1990

Ref. No. Speciﬁcation ISO 9060:1990 classiﬁcation SHP1

Secondary First Second First Standard Class Class Class

1 Response time

2 Zero o-set

Response 5 K/hr change in ambient temperature ± 1 W/m² ± 3 W/m² ± 6 W/m² < 1 W/m²

3a Non-stability (change per year, percentage of full scale) ± 0.5 % ± 1 % ± 2 % < 0.5 %

3b Non-linearity ± 0.2 % ± 0.5 % ± 2 % < 0.2 %

(percentage deviation from the responsivity at 500 W/m² due to any change of irradiance within the range 100 to 1000 W/m²)

3d Spectral sensitivity (percentage of deviation of the product of spectral ± 0.5 % ± 1 % ± 5 % < 0.5 %

absorptance and spectral transmittance from the corresponding mean within the range of 0.3 µm to 3 µm)

3e Temperature response

temperature within an interval of 50 K) -30°C to +60°C

3f Tilt response (percentage deviation from the responsivity at 0° tilt, horizontal, ± 0.2 % ± 0.5 % ± 2 % < 0.5 %

due to change in tilt from 0° to 90° at 1000 W/m² irradiance)

(95% response) < 15 s < 20 s < 30 s < 2 s

(percentage deviation due to change in ambient ± 1 % ± 2 % ± 10 % < 0.5 %

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Our customer support remains at your disposal for any maintenance or repair, calibration, supplies and spares.

Für Servicearbeiten und Kalibrierung, Verbrauchsmaterial und Ersatzteile steht Ihnen unsere Customer Support Abteilung zur Verfügung.

Notre service 'Support Clientèle' reste à votre entière disposition pour tout problème de maintenance, réparation ou d'étalonnage ainsi que pour les accessoires et pièces de rechange.

Nuestro servicio de atención al cliente esta a su disposición para cualquier actuación de mantenimiento, reparación, calibración y suministro de repuestos.

HEAD OFFICE

Kipp & Zonen B.V.

Delftechpark 36, 2628 XH Delft P.O. Box 507, 2600 AM Delft The Netherlands

T: +31 (0) 15 2755 210 F: +31 (0) 15 2620 351 info@kippzonen.com

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88 Avenue de l’Europe 77184 Emerainville France

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10 Ubi Crescent Lobby E #02-93 Ubi Techpark Singapore 408564

Kipp & Zonen USA Inc.

125 Wilbur Place Bohemia NY 11716 United States of America

Go to www.kippzonen.com for your local distributor or contact your local sales ofﬁce

T: +33 (0) 1 64 02 50 28 F: +33 (0) 1 64 02 50 29 kipp.france@kippzonen.com

T: +65 (0) 6748 4700 F: +65 (0) 6748 6098 kipp.singapore@kippzonen.com

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Passion for Precision