OTT Parsivel User manual

English
Operating instructions
Present Weather Sensor
Parsivel

We reserve the right to make technical changes!

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Table of contents
1 Scope of delivery 5
2 Part numbers 5
3 Parsivel Factory Settings 6
4 Safety instructions 7
5 Introduction 8
5.1 Functional principle 8
5.2 Connection Options for the Parsivel 9
6 Installing the Parsivel 10
6.1 Cable Selection 10
6.2 Wiring the Parsivel 11
6.3 Grounding the Parsivel 13
6.4 Installing the Parsivel 14
7 Connecting the Parsivel to a data logger 15
7.1 Connecting the Parsivel to the LogoSens Station Manager via RS-485 interface 15
7.2 Connecting the Parsivel to a Data logger via the SDI-12 Interface 17
7.3 Connecting the Parsivel to a Data Logger with Impulse/Status Input 21
8 Connecting the Parsivel to a PC 23
8.1 Connecting the Parsivel to Interface Converter RS-485/RS-232 (Accessories) 23
8.2 Connecting the Parsivel to the ADAM-4520 Converter RS-485/RS-232 (Accessories) 25
8.3 Connecting the Parsivel to Interface Converter RS-485/USB (Accessories) 26
8.4 Connecting the Parsivel to any RS-485 Interface Converter 27
8.5 Connecting the Parsivel for configuration via the Service-Tool to a PC 27
9 Connecting the Parsivel to a Power Supply (Accessory) 29
10 Heating the Parsivel sensor heads 30
11 Operating Parsivel with a Terminal software 31
11.1 Set up communications between the Parsivel and the terminal program 31
11.2 Measured value numbers 32
11.3 Defining the formatting string 33
11.4 OTT telegram 33
11.5 Updating Parsivel Firmware 34
12 Maintenance 36
12.1 Cleaning the laser’s protective glass 36
12.2 Keeping the light pathway open 36
12.3 Cleaning the splash protector 36
13 Functional disruptions and remedies 38
11.1 Parsivel does not start 38
11.2 Disruptions due to convection and vibrations 38
14 Technical data 39

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Appendix A: CS Command Set 40
Appendix B: Classification of precipitation types 43
B.1 Class limits 43
Appendix C: Characterization of precipitation type by precipitation codes 45
C.1 Precipitation code according to SYNOP 45
C.2 Precipitation code according to the NWS and METAR/SPECI w’w’, Table 4678 46
Declaration of Conformity 47

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1 Scope of Delivery
䊳Parsivel – 1 Parsivel measurement head is an optical sensor with 30 mm wide and
180 mm long light strip in the tunnel housing
– 1 Installation set with
1 screwed terminal strip 7 slots
7 wire end sleeves
1 grounding cable lug
1 flat washer
6 M 8 X 16 grub screws
7 M 8 X 25 grub screws
1 M8 hex nut
2 lock washers
1 Allen key - 4 mm
1 Allen key - 2.5 mm
– 1 Parsivel software ASDO Basic
– 1 set of operating instructions
2 Part Numbers
䊳Parsivel Parsivel 70.200.005.9.0
– with 2 special spray protection units
– with installation set
– with Parsivel software ASDO Basic
䊳Accessories Interface converter
– RS-485 / USB 97.961.091.9.5
– RS-485 / RS-232 97.970.041.9.5
Power supply Parsivel
IP 20, without mast support 97.850.011.9.5
IP 67, with mast support 97.850.012.9.5
Connecting cable Parsivel/Power supply IP 65 70.200.107.4.2
Connecting cable Parsivel/Electronic cabinet max. 100 m 97.000.038.9.5
Parsivel software ASDO for PC (full version) 56.551.001.9.7
LogoSens RS-485 termination module 70.200.803.9.5
Service Tool
consisting of
– interface converter RS-485/USB 97.970.044.9.5
– assembling cable for the interface converter 70.200.106.4.2
䊳Replacement Spray protection (1 piece) 70.200.405.3.1
parts

3 Parsivel Factory Settings
Parsivel is a flexibly configurable device concerning terminal assignment, interface
parameters and heating settings, and is supplied with the following factory set-
tings:
Operating mode: RS-485 2-wire
Baud rate RS-485: 19,200 baud
RS-485 bus mode: deactivated
Bus address RS-485: 0
SDI-12 interface: deactivated
SDI-12 bus address: 0
Impulse output 0.1 mm: activated
Status: solid=0, liquid=1
Heating mode: off
Data telegram: OTT telegram (see Chapter 11.4)
Measurement interval: 30 s
The parameters can be set using Parsivel software ASDO or using a terminal soft-
ware package. Information on the setting of these parameters is available in
Appendix A, “CS Command Set” or in the operating instructions “Parsivel Soft-
ware ASDO”.
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4 Safety Instructions
䊳These operating instructions contain basic instructions that must be followed
during installation, operation and maintenance. Therefore, it is absolutely nec-
essary that they be read by the assembler and by the responsible technical per-
sonnel/operator prior to installation and startup!
䊳These operating instructions must be accessible at the point of use of the mea-
surement device!
䊳Personnel responsible for installation, operation and maintenance must have
the appropriate qualifications for this work! Responsibilities, competency and
the monitoring of personnel must be closely controlled by the owner.
If personnel do not have the required knowledge, it must be provided through
training and instruction. If necessary, OTT MESSTECHNIK can provided this
service on a contractual basis for the owner.
䊳Non-adherence to these safety instructions can have dangerous consequences
for persons as well as for the measurement device!
䊳Non-adherence to these safety instructions can result in the loss of any indem-
nity claims!
䊳Please adhere to the safety instructions listed in these operating instructions,
to all existing national accident prevention regulations and to any internal
work, operating and safety rules as set forth by the owner!
䊳The operating safety of the delivered measuring device is only guaranteed
when it is used properly! Retrofitting or changing the measuring device is only
allowed if authorized by the manufacturer.
䊳To ensure safety, buy only original replacement parts and accessories autho-
rized by the manufacturer. Use of other parts can void liability for any conse-
quences arising therefrom!
䊳The Parsivel contains an embedded class 2 laser device and is a class 1/1M
laser product which complies with IEC/EN 60825-1 A2:2001 (EU) / 21CFR
1040.10 and 1040.11 (USA) with the exception of laser notice LN50.
Wavelength: 650 nm; output: max. 3 mW.
䊳Do not open the instrument and remove any barrier that would expose to laser
beam of embedded laser class 2 device!
䊳Do not stare into the beam or view directly with optical instruments!
䊳Optical light barriers must never be removed except by OTT Service personnel.
When barriers are removed, power to the Parsivel must be disconneted.
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5 Introduction
Parsivel is a laser-based optical system for complete and reliable measurement
of all types of precipitation. The size range of measurable liquid precipitation par-
ticles is from 0.2 … 5 mm, for solid precipitation particles it is from
0.2 … 25 mm. In the process, precipitation particles can have a velocity of from
0.2 … 20 m/s. The precipitation particles are categorized as follows:
䊳Drizzle
䊳Drizzle with rain
䊳Rain
䊳Rain, drizzle with snow
䊳Snow
䊳Snow grains
䊳Freezing rain
䊳Hail
The precipitation measurements are carried out using a special sensor head that
was developed for this particular purpose. It detects precipitation optically. The
data thus determined are processed and stored by a fast digital signal processor.
Parsivel issues one data telegram every 30 seconds.
5.1 Functional principle
The theory behind Parsivel is a laser sensor that produces a horizontal strip of
light. The emitter and the receiver are integrated into a single protective housing.
Measurement of particle size
If there are no particles in the laser beam, the maximum voltage is output at the
receiver. Precipitation particles passing through the laser beam block off a portion
of the beam corresponding to their diameter, thus reducing the output voltage; this
determines the particle size.
Measurement of particle speed
To determine the particle speed, the duration of the signal is measured. A signal
begins as soon as a precipitation particle enters the light strip and ends when it
has completely left the light strip.
Transmitter Receiver
Precipitation particle
Laser beam
Fig. 1: Functional principle of the Parsivel.
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The following parameters can be derived from these two determined quantities:
䊳Size spectrum
䊳Type of precipitation
䊳Kinetic energy
䊳Intensity of the precipitation
䊳Radar reflectivity
䊳Visibility
The spray protection attached to the sensor head prevents precipitation particles
from deflecting off the housing, falling into the laser beam and thus falsifying the
measurements.
5.2 Connection Options for the Parsivel
The Parsivel can be connected to various devices as shown in the illustration
below. Refer to the respective chapters in this regard.
Parsivel
Pipe
H = Total height
Disdrometer
general: 1 m
Present Weather
Sensor Parsivel: 2 m
Cable
max. 300 m
(RS-485)
Cable
max. 300 m
(RS-485)
Cable
max. 300 m
(RS-485)
Cable
max. 70 m
SDI-12
Interface
converter
Interface
converter
RS-485
LogoSens 2
Termination module
LogoSens
®
2
– ASDO Basic
Storage without
precipitation
spectrograph
– ASDO full version
Storage with
precipitation
spectrograph
– Hydras 3
online online
RS-232/USB RS-232/USB
RS-485/
2-wire
SDI-12
data logger
Power supply
Signal outputs:
RS-485
SDI-12
Impulse
Status
Impulse
+ Status
data logger
SDI-12
cable length
see
chap. 6.1
power supply
Chapter 8 Chapter 8 Chapter 7.1 Chapter 7.2 Chapter 7.3 Chapter 9
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6 Installing the Parsivel
Please follow Safty Instructions (see chapter 4) when installing
the Parsivel!
It is of critical importance to the quality of the measurements that the setup loca-
tion be selected carefully. Here, wind and vibrations must be minimized (see chap-
ter 13.2 „Disruptions due to Convection and Vibrations“). If the protection against
these influences is not sufficient, virtual drops can be detected.
Prerequisites
The Parsivel is mounted on a pipe. The pipe must have the following specifications:
䊳Pipe diameter 50 … 62 mm
䊳Pipe consists of an electrically conducting material and is grounded
䊳
The concrete foundation of the pipe must have minimum dimensions of
35 x 35 x 80 cm (L x W x H)
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Before the Parsivel can be fastened to the standpipe, the data transmission cable
and power supply must be installed.
6.1 Cable Selection
Data Transmission Cable
The Parsivel has the following signal outputs:
䊳RS-485
䊳SDI-12
䊳Impulse output
䊳Status output
We recommend that the data transmission cable has the following characteristics:
䊳Twisted-pair cable
䊳Usage length for transfer via the RS-485 interface, max. 300 m
䊳Usage length for transfer via the SDI-12 interface, max. 70 m
䊳Cable cross section ≥0.5 mm2
Power supply cable
For the 24 V power supply, we recommend a cable with a maximum resistance of
2Ω. The maximum voltage drop at 2 A is 4 V. The cable length depends on the
cable cross sectional area:
Cable cross section max cable length
0.25 mm214 m
0.5 mm228 m
0.75 mm242 m
1.0 mm256 m
1.5 mm284 m
2.5 mm2140 m
4.0 mm2225 m
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