Observator Instruments OMC-150 User manual

Manual | OMC-150
Status: Final | Not confidential
Page 1 | 38
V2.13
Manual
OMC-150
Version: 2.13
Status: Final
Date: 25 October 2019
Author: Observator
www.observator.com

Manual | OMC-150
Status: Final | Not confidential
Page 2 | 38
V2.13
Document history
The Observator range is in continuous development and so specifications may be subject to change
without prior notice. When in doubt about the accuracy of this document, contact the Observator Group.
Reference documents
Type of document / tool
Product type and name (incl. url)
Software
N.A.
Datasheet
OMC-150
Manual
OMC-150
Revision history
Date
Amendments
Company, position
1992-11-01
Initial document creation
Observator instruments
2000-5-29
V1.2 incorporating junction box
2003-8-27
V2.02 rewritten for ATEX certification,
incorporating plug connection
2004-1-29
V2.03 some typing errors corrected
2005-5-1
V2.04 minor error corrected (7core vs 8core)
2007-5-1
V2.05 annex G added
2013-4-1
V2.06 update certification (IECEx added) Review
version
2013-8-1
V2.07 Version 2.06 including all updated certificates
2015-12-1
V2.08 Update CE declaration
2016-12-1
V2.09 Update maintenance section
2017-5-1
V2.10 Update EU declaration
2019-1-2
V2.11 Update IP rating
2019-2-1
V2.12 Update DoC
2019-10-25
V2.13 Update DoC & style

Manual | OMC-150
Status: Final | Not confidential
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V2.13
Preface
This manual provides information for the best performance and safe application of the OMC-150
anemometer. This manual is intended for the engineers who are responsible for site planning, installation,
commissioning and maintenance of the intrinsically safe OMC-150 anemometer. Professional knowledge
on mechanical and electrical systems in potentially explosive atmospheres is required for the users of this
manual. This manual does not cover the OMC-156 junction box or the OMC-158 interface unit. These
units will come with their own documentation.
When an enumeration in this manual is numbered, it denotes a particular sequence. If the enumeration is
marked with dots, there is no special sequence.
Read this manual carefully before starting the installation of the Observator OMC-150 anemometer. Keep
this manual after installation for future reference.

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V2.13

Manual | OMC-150
Status: Final | Not confidential
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V2.13
Table of contents
1Introduction..................................................................................................................... 7
1.1 Utilisation.............................................................................................................................................7
1.2 General arrangement..........................................................................................................................7
1.3 Basic Specifications ............................................................................................................................8
1.4 Theory of Operation ............................................................................................................................8
1.5 Conditions of use.................................................................................................................................8
2Description...................................................................................................................... 9
2.1 General................................................................................................................................................9
2.2 Main parts............................................................................................................................................9
2.3 Moving parts........................................................................................................................................9
2.4 Electrical..............................................................................................................................................9
2.5 Layout of a wind system......................................................................................................................9
3Operation........................................................................................................................10
3.1 General..............................................................................................................................................10
3.2 Measurement of wind speed.............................................................................................................10
3.3 Measurement of wind direction .........................................................................................................10
4Safety..............................................................................................................................11
4.1 Safety measures by the design of the OMC-150 anemometer.........................................................11
4.2 System integration - interconnection to the other system components ............................................11
4.3 Required personnel qualification and remaining risks ......................................................................12
5Handling, transportation and storage...........................................................................13
5.1 Handling ............................................................................................................................................13
5.2 Long term storage .............................................................................................................................13
5.3 Reshipping the instrument.................................................................................................................13
6Installation......................................................................................................................14
6.1 Unpacking..........................................................................................................................................14
6.2 Location of the sensor.......................................................................................................................14
6.3 Location of the sensor.......................................................................................................................14
6.4 Mounting / mechanical installation ....................................................................................................14
6.5 Assembly of cup and vane ................................................................................................................15
6.6 Alignment of the wind vane...............................................................................................................16
6.7 Electrical installation..........................................................................................................................17
7Commissioning..............................................................................................................18
8Faults, support, and service..........................................................................................19
8.1 Faults.................................................................................................................................................19
8.2 Support, service and warranty...........................................................................................................20
9Maintenance...................................................................................................................21
9.1 Maintenance schedule (preventive maintenance).............................................................................21
9.2 Removing the OMC-150 anemometer from its location....................................................................21
9.3 Recalibration......................................................................................................................................22

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10 End of operational life ...................................................................................................23
Appendix A: Typical system layout.......................................................................................24
Appendix B: OMC-150 Specifications....................................................................................26
Appendix C: Drawings............................................................................................................27
Appendix D: Spare Parts........................................................................................................30
Appendix E: OMC-150 Marking..............................................................................................31
Appendix F: ATEX certificate.................................................................................................32
Appendix G: IECEx certificate................................................................................................34
Appendix H: EU Declaration of Conformity...........................................................................37

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1 Introduction
1.1 Utilisation
The OMC-150 anemometer is designed to measure wind speed and wind direction in harsh environments
including potentially explosive atmospheres. Typical application areas are offshore industry, petrochemical
industry, and transportation. All exposed parts are made in non-corrosive materials, therefore the OMC-
150 anemometer is ultimate suitable for marine environment.
1.2 General arrangement
Figure 1 General Arrangement

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1.3 Basic Specifications
parameter
value
Type of instrument
anemometer
EX-certification
ATEX Ex ia IIC T4
Measuring principle
cup and vane
Mounting
pole-mounting
Main dimensions
approx. 450 x 460 x 905 mm
Weight including cup unit and vane unit
approx. 5 kgs
Electrical connection
7-pole plug
Output signal compatibility
direct connection to Obsermet OMC-158
Measuring range (wind speed)
0 … 75 m/s
Measuring range (wind direction)
0 … 360 degrees (no gap)
Table 1 Basic Specifications
1.4 Theory of Operation
The OMC-150 is a cup and vane anemometer. Cup and vane anemometers are the most common
instrumentation for measurement of wind speed and direction. Cup and vane anemometers are the
primary sensors for wind measurement used by the leading meteorological services all over the world.
Therefore the readings of the OMC-150 anemometer are intercomparable with the readings of other cup
and vane anemometers without any conversions.
For a more comprehensive discussion on the measurement principle please refer to Chapter 5 of the
WMO CIMO guide
1
1.5 Conditions of use.
The OMC-150 anemometer is built to provide reliable measurement results under all weather conditions.
Rain, snow, or other kinds of precipitation do not effect the readings. Further the OMC-150 anemometer is
insensitive to noise, extreme temperatures, solar radiation, etc.
1
Guide to Meteorological Instruments and Methods of Observation, WMO No. 8, latest Edition, World Meteorological Organisation,
Geneva, Switzerland

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2 Description
2.1 General
While reading this chapter please refer to the dimensional drawing in Appendix C:For detailed
specifications please refer to Appendix B:
2.2 Main parts
The OMC-150 anemometer consists of a sensor body and a mounting bracket. Note that the mounting
bracket, though it is sometimes referred to as OMC-157, is an integral part of the OMC-150 anemometer.
The mounting bracket has a mast clamp and an electrical plug connector. This clamp is designed for
mounting on a vertical pipe end.
2.3 Moving parts
The only moving parts are the cup unit and the vane unit. The vane unit is mounted on top of the sensor
body, and the cup unit is mounted under the sensor body. Both the cup unit and the vane unit are wind
driven. The wind speed sensor is a rotary cup type unit manufactured in stainless steel and polycarbonate.
The three cups are cone shaped for optimum response to varying winds. The vane unit is made in
stainless steel.
2.4 Electrical
The electrical circuit for wind speed measurement and the electrical circuit for wind direction measurement
are not interconnected. The speed sensor is a proximity switch with a 2-wire “NAMUR” signal on
connections E and F; the direction sensor is a dual wiper potentiometer with a 360 degree winding (no
gap). It has two supply connections A and B, and two wiper connections C and D. For details see section
3.3.
2.5 Layout of a wind system
The following accessories are supplied with the OMC-150 anemometer:
pigtail cable with mating connector to the OMC-150 anemometer
U-bolts with small mounting materials
In order to build a complete wind system, the following components may be required. These components
must be ordered separately:
OMC-156 Junction box for cable extension
Field cabling
OMC-158 interface unit
Calibration certificate (see also section 0)

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See Appendix A: for a typical system layout. Note that the maximum length of the field cable, which runs
from the junction box (nearby the OMC-150 anemometer) through the Ex zone to the OMC-158-2
interface unit, is up to 1 km (depending on the cable quality).
3 Operation
3.1 General
The numbers in parenthesis refer to the item numbers on the assembly drawings in
3.2 Measurement of wind speed
The cup unit (6) is driven by the wind. There is an almost linear dependency between wind speed and
rotational velocity of the cup unit. The proportional factor is 1.68 meters per revolution. The cup unit is
connected to a shaft (12), which drives a metal slotted code cap (16). The transitions between the metal
partitions and the slots in this code cap generate pulses by means of an inductive proximity switch (10).
The code cap generates 8 pulses per revolution, so each pulse represents 0.21 meters
3.3 Measurement of wind direction
The stainless steel vane unit (4, 5) is driven by the wind. It turns until the counterweight (5) directs into the
wind direction. The position of the vane unit is transmitter through the shaft (12) and the coupling (17, 18)
to the dual wiper potentiometer (8). Figure 2 shows the typical output voltage in relation to the vane
position.
0 V 0 º 90 º 180 º 270 º 360 º
C
D
N E S W N
Figure 2 Output voltage on terminals C and D of the dual wiper potentiometer