Omega HHM290, Instruction Manual

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4 13
Safety Warnings and IEC Symbols
This device is marked with international safety and hazard sym-
bols in accordance with IEC 1010. It is important to read and follow
all precautions and instructions in this manual before operating or
commissioning this device as it contains important information
relating to safety and EMC. Failure to follow all safety precautions
may result in injury and or damage to your equipment. Use of this
device in a manner not specified by the manufacturer may impair
protection provided within the unit.
IEC symbols Description
Caution-Risk of Electric shock
Caution-Refer to Accompanying documents
Direct Current
Alternating Current
Earth (Ground) Terminal
Equipment protected throughout by Double
Insulation
Laser Symbol
OPERATION
Before taking any measurements, read the Safety Information
Section. Always examine the instrument for damage, contamina-
tion (excessive dirt, grease, etc.) and defects. Examine the test
leads for cracked or frayed insulation. If any abnormal conditions
exist do not attempt to make any measurements. For normal
operation when changing ranges through OFF range, please wait
for one second.
FUNCTIONS OF BUTTONS
Button
When the unit is turned on, the Auto Power-On (APO) mode is
disabled meaning that the meter shuts itself off after about 30
minutes of continuous operation. This feature saves battery life if
the meter is un-attended.
Pressing the button, enables the APO mode, and an APO
icon appears on the display meaning that the meter will not shut
itself off unless it is turned off by the user. This feature is also
desirable when the meter is used to monitor a parameter for an
extended period of time. Using the DC adapter, it will take over the
battery power to save battery life. Pressing the
button again
will disable the APO mode.
Button (Double Duty)
Pressing this button will toggle between AC and DC current
measurement. In infrared temperature measurement "IR" mode,
pressing this button decreases the Emissivity value of the target.
How to specify the target emissivity
In order to determine an unknown target Emissivity:
1. Set the Function switch to T/C.
2. Plug in a K type surface thermocouple probe to the meter.
3. Measure the target temperature using the surface probe.
4. Unplug the surface probe from the meter.
5. Set the Function switch to IR.
6. Aim at the target. Press & hold the
button to turn on the
laser beam for positioning.
7. Adjust the Emissivity button until the meter reads the same
temperature measured via the thermocouple probe. Read the
new Emissivity setting.
Measurement Considerations
1. Theory of Measurement
Every object emits infrared energy in accordance with its
temperature. By measuring the amount of this radiant energy, it
is possible to determine the temperature of the emitting object.
2. About Infrared
Infrared radiation is a form of light (electromagnetic radiation),
and has the property that it passes easily through air while it is
easily absorbed by solid matter. With an emission thermometer
which operates by detecting infrared radiation accurate mea-
surement is possible, irrespective of the air temperature or the
measurement distance.
3. Emission Thermometer Structure
Infrared radiation which has been emitted from the object is
focused upon an infrared radiation sensor, via an optical sys-
tem. This includes a lens which is transparent to infrared
radiation, and 5.3µm cut off filter. The output signal from the
infrared radiation sensor is input to an electronic circuit along
with the output signal from a standard temperature sensor
(Thermopile).
4. Emissivity
All objects emit invisible infrared energy. The amount of energy
emitted is proportional to the object's temperature and its ability
to emit IR energy. This ability, called emissivity, is based upon
the material that the object is made of and its surface finish.
Emissivity values range from 0.10 for a very reflective object to
1.00 for a black body. Factory set emissivity value of 0.95, which
cover 90% of typical applications.
5. If the surface to be measured is covered by frost or other
material, clean it to expose the surface.
6. If the surface to be measured is highly reflective, apply masking
tape or matt finish black paint to the surface.
7. If the meter seems to be giving incorrect readings check the front
lens. There may be condensation or debris obstructing the lens;
clean per instructions in the maintenance section.
Substance Thermal Substance Thermal
emissivity emissivity
Asphalt 0.90 to 0.98 Cloth (black) 0.98
Concrete 0.94 Human skin 0.98
Cement 0.96 Lather 0.75 to 0.80
Sand 0.90 Charcoal (powder) 0.96
Earth 0.92 to 0.96 Lacquer 0.80 to 0.95
Water 0.92 to 0.96 Lacquer (matt) 0.97
Ice 0.96 to 0.98 Rubber (black) 0.94
Snow 0.83 Plastic 0.85 to 0.95
Glass 0.90 to 0.95 Timber 0.90
Ceramic 0.90 to 0.94 Paper 0.70 to 0.94
Marble 0.94 chromium oxides 0.81
Plaster 0.80 to 0.90 Copper oxides 0.78
Mortar 0.89 to 0.91 lron oxides 0.78 to 0.82
Brick (red) 0.93 to 0.96 Textiles 0.90