Comark C22 T User Manual
Comark C20 Series Handheld
Thermometers
Models C21, C22, C26 and C28
Operator Manual
Description
The C20 series handheld thermometers represent a leap
forward in case design and specification combining a number
of innovative features with an advanced performance.
C20 series thermometers all have a high strength,
polycarbonate case with rubber over moulding. This offers a
very high level of strength, durability and protection against
dust and water ingress. The C20 range is certified to meet
IP67. All models incorporate a clock, countdown tim er and
data hold feature. For the full range of features please refer to
Appendix 1, Page 7.
Overview of Display Symbols
A B C D E
HOLD SET MENU
BAT
PSTK
°C
°F
F
¥
G
A – Indicates that HOLD has been selected.
B – Setting menu item to ON/OFF
C – Indicates Low Battery.
D – The Set Up menu is active.
E – Indicates probe type.
F – Main Display for Temperature
G – Clock Indicator.
H – Display for time and countdown timer.
I – Indicates countdown active.
J – Alarm indication
H I J
1
Connecting Probes to the Thermometers
C20 series thermometers have either sub-miniature or
Lumberg sockets for probe connection and offer a class
leading choice between Comark thermistor, type T
thermocouple or type K thermocouple probes.
The polarity of the connector must always be checked before
connecting thermocouple probes to C20 series thermometers.
A probe of the correct thermocouple type must also be
selected to match the specific thermometer. C20 series
thermometers with Lumberg sockets will automatically detect
the sensor type of the probe connected. The LCD will then
indicate thermistor probes as “PST”, and type T thermocouple
probes as “T”. Models with Sub-Min connector are of fixed
thermocouple type, see specifications for details.
Switching On and Off
Display Test/Mode
The ‘ON/OFF’ button on the keypad is used to switch on the
thermometer. After a short pause the display will show the
current model of the instrument and will then revert to normal
temperature display. The current time is also permanently
displayed on the LCD.
Data Hold
All C20 series thermometers have a data hold facility. If the ‘II’
button is pressed at any time during normal temperature
mode, the current temperature will be held on the display. To
release press ‘II’.
Countdown Timer
All C20 series thermometers have a countdown timer. This
function is activated from the Set Up Menu – see section
below, and can be calibrated in seconds/minutes or hours.
Pressing the countdown timer button will start this function.
Pressing the button again during the countdown period will
stop the count. The instrument will beep for 30 seconds at the
end of a countdown period to indicate to the user that it has
been comple ted.
Auto Switch Off/Power Saving Mode
C20 series thermometers have a selectable auto-switch off
feature. This is set to 3 minutes from the factory. Please refer
to Set Up Menu for instructions on changing this setting.
Set Up Menu
C20 series thermometers have a hidden menu structure that
is used to set up a number of parameters within the
instrument. See Appendix 1 on Page 7 – C20 Series Model
Range Options, to see which options are available on each
model.
The set up menu can be entered when the instrument is
switched on.
To enter the set up menu first ensure the instrument is off,
then press the Count Down button and keep this held down
while pressing the On button to switch the instrument on.
After the thermometer has completed its self-checks, it will
enter the menu.
N.B. After each menu item use the ON/OFF button to save
and move to the next menu item.
Clock selection is the first item in the menu:
Clock – the display will show ‘CLOC’
Use the countdown timer button and the hold button to adjust
the clock time up or down.
Countdown Timer – the display will show ‘Cd’
Use the countdown timer button and the hold button to select
timer on or off. Use the Hold and Countdown timer buttons to
scroll up and down in seconds up to 5 minutes then in 1
minute intervals up to 24 Hours.
Scale – the display will show ‘SCAL’
After entering the SCALE menu, use the Countdown Timer
button and the Hold button to scroll between the available
scales.
High Alarm – the display will show ‘HIAL’
Use the countdown timer and hold buttons to select or deselect high alarms, then select the required high alarm value.
2
3
Low Alarm – the display will show ‘LOAL’
Use the countdown timer and hold buttons to select or deselect low alarm, then select the required low alarm value.
Auto Power OFF – the display will show ‘AOFF’
Use the countdown timer button and the hold button to scroll
between the available options of 3, 10, 30 minutes or none.
Clock Alarms – the display will show AL 1, followed by
AL 2 and AL 3
Three Clock Timer Alarms can be set. Use the countdown
and hold buttons to select or deselect Clock Alarm, and then
to select the required time. Note that on instruments with no
AM or PM indicator it will show the change by the way the
time changes over midnight or noon. At midnight the display
will change from 11:59 to 0:00, indicating AM, and at noon the
display will change from 11:59 to 12:00, indicating PM.
Repeat for AL 2 and AL 3.
Resolution – the display will show ‘HrES’
Use the countdown and hold buttons to select or de-select
temperature display in high resolution 0.1° or low resolution
1°.
Care of the Thermometer
C20 series thermometers are dust and waterproof as stated in
the specifications and will withstand harsh environments. Use
a damp cloth or warm soapy water to remove deposits and
prevent them from hardening or becoming sticky. Do not use
solvent-based cleaners or methylated spirit, etc.
Caution: Do not place any C20 series thermometers in a
dishwasher.
Specifications Continued
Ambient Temperature Range
Display 4 digit, 12.5 mm LCD
Battery Two Type I.E.C. LR6 Size AA
Battery Life (continuous) Up to 14000
Up to 7000
Environmental IP67, BS 60529, IEC 529
Protection
EMC Emission Tested to EN61326-1
Criteria B Performance
Dimensions
Length 152mm/6 inches
Width 58mm/2.3 inches
Depth 22/27mm/09./1.1 inches
Weight 178g/6.3 ozs
-20°C (-4°F) to +50°C (122°F) operating
hours with thermistor probes
hours with thermocouple probes
6
Changing the Batteries
The symbol BAT appears on the display when the battery
voltage has reduced. Battery replacement is recommended at
this time.
To replace the battery, remove the battery cover retaining
screw on the rear of the instrument, using the correct size
screwdriver. Remove the two cells, and replace with alkaline
cells only. Be careful to observe the correct polarity. Take
care not to over-tighten the screw when refitting the cover.
Note: The C20 series thermometers will not work if the battery
compartment is incorrectly fitted or missing. In this instance
the display will show ‘OPEn’. Please note the small pip on the
inside of the battery cover, which must fit into the hole
provided in the back of the case.
Specifications for C20 Series Thermometers
Measurement
Thermocouple type T and K
6-pin Lumberg and Sub-Min Connector s
Measurement Range
Scales °C and °F
Displayed Resolution 0.1° > - 100°
1° ≤ -100°
Instrument Accuracy
Thermocouple 0.1% ± 0.2°C(0.4°F) full range
@ 23°C Ambient
Thermistor ±0.3°C (±0.6°F)
System Accuracy 0°C (32°F) to 70°C (158°F)
±0.5°C (±0.9°F)
-25°C (-13°F) to 100°C (212°F)
Temperature Coefficient
Thermistor less than 0.005°C/°C (0.01°F per °F)
Thermocouple less than ± 0.01 % of reading ±0.02 °C per °C
(±0.04°F per °F) change from 23°C
4
Appendix 1 – C20 Series Model Range Options
Thermistor 10 K Ohms unicurve
-50°C(-58°F) to +150°C(302°F) Thermisto r
-200°C(-328°F) to 400°C(752°F) Type T
-200°C(-328°F) to 600°C(1112°F) Type K
@ 23°C Ambient
Models C21 C22
Part No. C21 C22 C22F C26 C28F
Options
Countdown
Timer
Data Hold
Real Time
Clock
Clock
Alarms
Scale
Selection
High Alarm - -
Low Alarm - High
Resolution
Type T -
Type K - - - -
Thermistor
Connector* L L L S S
Auto Off
IP67
* L – Lumberg
S – Sub-Miniature
7
9 9 9 9 9
9 9 9 9 9
9 9 9 9 9
- - - -
9 9 9 9 9
9 9 9 9 9
9 9 9
9 9 9 9 9
9 9 9 9 9
C22 T
Type
9
9
9 9 9
C28 K
C26
Type
9
9
-
9
-
-
9
- -
5
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