Omega 24 User manual

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User’s Guide
CL23A, 24, 25, 26, 27
Digital Calibrator/Thermometer

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WARNING: These products are not designed for use in, and should not be used for, patient connected applications.

TABLE OF CONTENTS
General Information......................................................................... 2
Common Specifications................................................................... 2
Unique Specifications...................................................................... 5
Features........................................................................................... 6
Manual Addenda ............................................................................. 6
Unpacking Your Unit........................................................................ 7
Safety Information ........................................................................... 7
Safety Precautions .......................................................................... 7
Battery Installation/Replacement..................................................... 9
Memory Backup.............................................................................. 10
Operation with Rechargeable Battery............................................. 10
Operating Instructions..................................................................... 11
11. Diagnostics and Error Messages...................................... 11
12. Initial Turn On................................................................... 11
3. Meter Mode Operation (Thermocouple) ........................... 13
14. Meter Mode Operation (RTD, Thermistor, Ohms)............ 14
15. Data Logging & Recall...................................................... 15
16. Calibrator Mode Operation (Thermocouples)................... 17
17. Calibrator Mode Operation (RTD, Thermistor, Ohms) ..... 18
18. Storage and Recall of Calibrator Settings ........................ 20
9. Step Function.................................................................... 22
10. Ramp Function ................................................................. 22
Service Information......................................................................... 23
11. Calibration Procedures ..................................................... 23
12. Calibration Verification...................................................... 32
13. Mechanical Parts Diagram................................................ 38
Warranty......................................................................................... 45
Limitation of Warranty..................................................................... 45
Statement of Calibration................................................................. 45
1

GENERAL INFORMATION
This manual provides operating instructions and maintenance information for
five temperature instruments. These instruments are high performance cali-
brator-thermometers capable of simulating and measuring a wide-variety of
sensors. In addition, features such as data storage and ramping further
enhance their versatility.
It is recommended that you read this manual thoroughly, especially the sec-
tions on safety, prior to operating these instruments.
COMMON SPECIFICATIONS
THERMOMETER INPUTS: THERMOCOUPLE; Miniature TC jack. RTD, OHMS,
THERMISTOR; T-series instrumentation connector.
CALIBRATOR OUTPUTS: THERMOCOUPLE; Miniature TC jack. RTD, OHMS,
THERMISTOR; T-series instrumentation connector.
THERMOCOUPLE TYPES: K, J, T, E, N, B, R, S, G, C, D.
RTD TYPES: 1100Ωplatinum (∝= 0.00385)
1000Ωplatinum (∝= 0.00385)
THERMISTOR TYPE: 2252Ω(YSI Series 400).
RANGES: RTK; –200°C to 1372°C, –328°F to 2502°F
RTJ; –210°C to 760°C, –346°F to 1400°F
RTT; –200°C to 400°C, –328°F to 752°F
RTE; –230°C to 1000°C, –382°F to 1832°F
RTN; –200°C to 1300°C, –328°F to 2372°F
RTB; 500°C to 1820°C, 932°F to 3308°F
RTR; 0°C to 1768°C, 32°F to 3214°F
RTS; 0°C to 1768°C, 32°F to 3214°F
RTG; 300°C to 2316°C, 572°F to 4201°F
RTC; 0°C to 2316°C, 32°F to 4201°F
RTD; 0°C to 2316°C, 32°F to 4201°F
RTD; –200°C to 850°C, –328°F to 1562°F
THERMISTOR; –40°C to 150°C, –40°F to 302°F
OHMS; 0-999.99Ω
OHMS; 0-9,999.9Ω
OHMS; 0-99,999Ω
ACCURACY (18°C to 28°C ambient, 2 years)*:
K, J, T, E, N; ± 0.5°F (rdg ≥–50°F)
K, J, T, E, N; ±1.0°F (rdg < –50°F)
B, R, S, G, C, D; ±1.7°F
2

3
RTD; ±0.2°F (rdg ≥– 50°F)
RTD; ±0.5°F (rdg < – 50°F)
RTD; ±0.2°F ±0.04% rdg (meter mode)
THERMISTOR; ±0.5F
OHMS; ±0.02% range
* Exclusive of sensor errors, and lead resistance induced errors.
RESOLUTION: TEMPERATURE; 0.1°/1° F/C
RESOLUTION: OHMS; 0.01Ω/0.1Ω/1Ω
REPEATABILITY (1 week at constant ambient temperature):
K, J, T, E, N; ±0.2°F typ.
B, R, S, G, C, D; ±1.0°F typ.
RTD, THERMISTOR; ±0.1°F typ.
OHMS; ±0.01% rng typ.
TEMPERATURE COEFFICIENT:
From 18°C to 28°C, included in accuracy specifications.
From 0°C to 18°C, and 28°C to 50°C:
K, J, T, E, N; ±(0.002% rdg + 0.03°C)/°C
B, R, S, G, C, D; ±(0.002% rdg + 0.1°C)/°C
RTD, THERMISTOR, OHMS; ±(0.002% rdg + 0.004% rng)/°C
METER-MODE INPUT-CURRENT (THERMOCOUPLES): 50nA typ.
METER-MODE READING-RATE: 1 reading/second typ.
METER-MODE EXCITATION-CURRENTS:
100ΩRTD; <2mA
1000ΩRTD; <200µA
999.99Ω; <2mA
9999.9Ω; <200µA
99999Ω; <50µA
THERMISTOR; T ≤113°F <50µA
T> 113°F, <2mA
CALIBRATOR MODE OUTPUT LOAD (THERMOCOUPLES): 500Ωmin.
CALIBRATOR-MODE EXCITATION-CURRENTS:
100ΩRTD; 0.5 – 1mA (0.1 – 2mA typ.)
1000ΩRTD; 50 – 100µA (10-200µA typ.)
999.99Ω; Same as 100ΩRTD
9999.9Ω; Same as 1000ΩRTD
99999Ω; 10 – 20µA (1 – 20µA typ.)
THERMISTOR; T ≤113°F, 10 – 20µA
T> 113°F, 0.5 – 1mA
MAXIMUM COMMON MODE VOLTAGE: 42V peak to earth.

4
KEYPAD: 12 momentary switches with tactile feedback select;
• On/Off
• Change/Enter
• Clear/–0
• Sensor Select/1
• °F/°C/2
• Resolution/3
• Operate/4
• Store/5
• Recall/6
• Calibrator/Meter/Up Ramp/7
• Calibrator Step/Down Ramp/8
• Calibrator Ramp/Meter Hold/9
DISPLAY: 5 digit LCD, 0.4" height, and decimal point. Annunciators;
• Loaded Memory Locations (10 for data storage, 4 for ramp parameters)
• Low Battery (BAT)
• Number Change Mode (NUM)
• Calibrator Mode (CALIB)
• Meter Mode (METER)
• Operate Mode (OPR)
• Store Mode (STO)
• Recall Mode (RCL)
• Meter Hold (HOLD)
• Scale (°F/°C)
• Sensor Type
POWER OFF CONFIGURATION RETENTION: Instrument retains last selected;
• Sensor Type
• °F/°C Scale
• 0.1°/1° Resolution
• Calibrator/Meter Mode
• Memory Contents (data storage and ramp parameters).
DIAGNOSTICS: Display codes indicate following conditions;
• 'BAT': Low Battery
• 'OPEN': Open Input Thermocouple, RTD or Thermistor.
• 'E-1' (momentary): Invalid Keypad Entry
• 'E-2' (momentary): Ramp Function Not Installed
• 'HI': Temperature Reading or Keypad Entry Exceeds Rating
• 'LO': Temperature Reading or Keypad Entry Too Low For Accuracy
• LCD Test: During power-up, all segments and annunciators enabled momentarily
ENVIRONMENTAL LIMITS FOR OPERATING: 0°C to 50°C, less than 90% relative
humidity (R.H.) up to 35°C; reduce R.H. limit by 3%/°C from 35°C to 50°C.
ENVIRONMENTAL LIMITS FOR STORAGE: –35°C to 60°C, less than 95% relative
humidity (R.H.) up to 35°C; reduce R.H. limit by 3%/°C from 35°C to 60°C.
POWER: 9 volt alkaline battery (NEDA 1604A).

5
BATTERY LIFE, CONTINUOUS: 10 hrs. typical, alkaline; 3 hrs typical, Ni-Cd
(rechargeable).
BATTERY INDICATOR: Display indicates BAT when less than 10% of life remains.
DIMENSIONS, WEIGHT: 7.0" ×2.9 × 1.1". Net weight 12 oz.
UNIQUE SPECIFICATIONS
NOTE: The specifications below are specific to the model(s) as identified by model
number. The difference specifications are in addition to the OVERALL SERIES SPEC-
IFICATIONS found on pages 2-5.
•MODEL CL23A/CL23EC:
SENSOR SELECTION: K, J, T/K, J, T, L Thermocouples
ACCURACY: (18°C to 28°C ambient, 2 years): ±0.5°F (rdg ≥–50°F).
±0.04% rdg (rdg > 1250°F)
±1.0°F (rdg < –50°F)
TEMPERATURE COEFFICIENT: 18°C to 28°C; included in accuracy specifications.
From 0°C to 18°C, and 28°C to 50°C; less than ±(0.006% rdg +0.03°C)/°C.
RAMP FUNCTION: Not Included.
BATTERY LIFE, CONTINUOUS: 16 hrs typical, alkaline; 4 hrs typical, Ni-Cd
(rechargeable).
•MODEL CL24:
SENSOR SELECTION: K, J, T, E Thermocouples
ACCURACY: (18°C to 28°C ambient, 2 years): ±0.5°F (rdg ≥–50°F).
±0.04% rdg (rdg > 1250°F)
±1.0°F (rdg < –50°F)
TEMPERATURE COEFFICIENT: 18°C to 28°C; included in accuracy specifications.
From 0°C to 18°C, and 28°C to 50°C; less than ±(0.006% rdg +0.03°C)/°C.
RAMP FUNCTION: Not Included.
BATTERY LIFE, CONTINUOUS: 16 hrs typical, alkaline; 4 hrs typical, Ni-Cd
(rechargeable).
•MODEL CL25/CL25EC:
SENSOR SELECTION: K, J, T, E, N, B, R, S, G, C, D/K, J, T, E, N, B, R, S, L, C,
D Thermocouples
RAMP FUNCTION: Included.
BATTERY LIFE, CONTINUOUS: 16 hrs typical, alkaline; 4 hrs typical, Ni-Cd
(rechargeable)
•MODEL CL26:
SENSOR SELECTION: K, J, T, E Thermocouples
100ΩPlatinum RTD
2252ΩThermistor
1,000Ω/100,000ΩResistance

ACCURACY: (18°C to 28°C ambient, 2 years): ±0.5 °F (rdg ≥–50°F).
±0.04% rdg (rdg > 1250°F)
±1.0°F (rdg < –50°F)
OHMS; ±0.04% range
TEMPERATURE COEFFICIENT: 18°C to 28°C; included in accuracy specifications.
From 0°C to 18°C, and 28°C to 50°C.
K, J, T, E; ±(0.006% rdg + 0.03°C)/°C
RTD, THERMISTOR, OHMS; ±(0.006% rdg +0.012% rng)/°C
RAMP FUNCTION: Not Included.
•MODEL CL27/CL27EC:
SENSOR SELECTION: K, J, T, E, N, B, R, S, G, C, D/K, J, T, E, N, B, R, S, L, C,
D Thermocouples
100Ω/1000ΩPlatinum RTD
1,000Ω/10,000ΩResistance
RAMP FUNCTION: Included.
FEATURES
• Combination calibrator, thermometer and datalogger.
• Function selection and numeric data entered via 12 keyswitch color coded
keypad.
• Keyswitches have tactile feedback.
• 5 digit LCD includes annunciators for operating modes.
• Up to 11 thermocouple types, 2 RTD types, and thermistor.
• 1° or 0.1° resolution over temperature range of each sensor.
• °F and °C scales.
• Reading hold mode.
• 10 memory locations for saving meter readings and/or calibrator outputs.
• Step mode for quick sequential recall of calibrator outputs from memory.
• Manual/automatic ramping for testing controller setpoints.
• Conforms to ITS-90 thermocouple tables.
• Dust proof, splash proof, drop proof construction.
• Built-in tilt stand/hanger for bench use or hands free field measurements.
• User friendly programming.
• Retains data and programming, even when turned off.
• Performs diagnostic tests and indicates fault conditions.
• Low battery and open sensor indications.
MANUAL ADDENDA
Improvements or changes to this manual will be explained on an addendum
included with the instrument. All change information should be incorporated
immediately into the appropriate places in the manual.
6

UNPACKING YOUR UNIT
Remove the Packing List and verify that you have received all equipment. If
you have any questions about the shipment, please call the OMEGA
Customer Service Department at 1-800-622-2378 or [phone].
When you receive the shipment, inspect the container and equipment for any
signs of damage. Note any evidence of rough handling in transit. Immediately
report any damage to the shipping agent.
NOTE: The carrier will not honor any claims unless all shipping
material is saved for their examination. After examining and
removing contents, save packing material and carton in the event
reshipment is necessary.
Make sure that you have the following items in the packing box.
• 1 CL20 Series Calibrator and Holster.
• 1 Operator’s Manual
• 1 NIST Certificate
• 1 Accessories Kit
SAFETY INFORMATION
SAFETY SYMBOLS AND TERMS
The symbol on the instrument denotes that the user should refer to the
operating instructions.
The WARNING used in this manual explains dangers that could result in
personal injury or death.
The CAUTION used in this manual explains hazards that could damage
the instrument.
SAFETY PRECAUTIONS
WARNING
These instruments are intended for use by qualified person-
nel trained in the safe operation of electronic testing equip-
ment. Read the instruction manual thoroughly before using,
to become familiar with the instrument's operations and
capabilities.
▲▲
!
7

WARNING
Do not touch a temperature probe sheath when measuring
excessively high or low temperatures, or toxic substances.
WARNING
Do not attempt to measure temperatures beyond the range of
the probe being used. Probe damage or personal injury
could result from exceeding a probe's maximum temperature
rating.
WARNING
The American National Safety Institute (ANSI) states that a
shock hazard exists when probes or sensors are exposed to
voltage levels greater than 42VDC or 42V peak AC. Do not
use this instrument where voltages at the measurement sur-
face exceed these levels.
WARNING
Do not substitute a metal part for the nylon screw in the rear
case. Doing so will degrade electrical isolation of the case.
WARNING
The battery is accessible through a cover on the back of the
instrument. To avoid electrical shock hazard, disconnect all
temperature probes and sensors and turn the unit off before
removing the cover.
WARNING
Never use this instrument or any probe or sensor inside a
microwave oven.
CAUTION
Avoid making sharp bends in probe or sensor lead wires.
Bending lead wires at a sharp angle can damage the wire
causing probe failure.
8

CAUTION
Keep inputs electrically isolated from outputs. Do not con-
nect an external voltage source between the two connectors,
and avoid any external electrical pathways between input
and output (T2 & T1).
Failure to do so will disturb meter readings and calibrator
output levels. Damage to the instrument is also possible.
Where the meter and calibrator connectors are simultane-
ously wired into a system lacking the above isolation, it is
necessary to use an "ungrounded" (i.e. electrically isolated)
probe at the thermometer input.
BATTERY INSTALLATION/REPLACEMENT
A 9V alkaline battery is supplied with the instrument but not installed. Read
the following installation instructions before attempting to install or remove
the battery. Replacement batteries should also be alkaline types.
WARNING
Turn the unit off and disconnect any input/output connec-
tions before replacing the battery. Put the cover back into
place on the battery compartment before resuming use of
the instrument.
1. Remove the cover from the battery compartment by sliding it off in the
direction of the arrow located on the battery cover.
9
Figure 1. Battery Installation

2. Remove the old battery by lifting the battery extractor loop.
3. Place the new battery in the battery compartment. Be sure to observe
proper polarity.
4. Re-install the battery cover before resuming use of the instrument.
NOTES:
• Less than 10% of battery life remains when the BAT annuncia-
tor turns on.
• When the battery is excessively discharged, the display is
blanked.
• If the instrument is going to be stored for a long period of time
or in a high temperature environment, remove the battery to
prevent leakage damage.
•After a new battery is installed, allow approximately 5 sec-
onds for display turn-on the first time the unit is turned on.
During this period, microcomputer initialization is per-
formed.
MEMORY BACKUP
During battery replacement, the contents of user-programmed memory
(data, operating modes, etc.) can be saved. Prior to removing the old battery,
turn off the instrument, and connect an HH22-AC battery charger. Then
exchange batteries, and disconnect the battery charger. Do not leave the bat-
tery charger connected to instruments with non-rechargeable batteries.
OPERATION WITH RECHARGEABLE
BATTERY
HH22-AC provides a 9-volt Ni-Cd battery and recharger suitable for use with
the unit. This battery provides 3-4 hours of continuous operation. This dura-
tion can be extended to several days by operating simultaneously from both
the battery and recharger.
Turn off the instrument to recharge the battery. Allow 7 hours to fully
recharge the battery. Then unplug the recharger to avoid overcharging.
10

OPERATING INSTRUCTIONS
1. DIAGNOSTICS AND ERROR MESSAGES
Unit self-diagnostics provide fault condition readouts which are described
below:
PROBLEM: LIKELY CAUSE:
Blank display, unit does not (1) Improper battery installation.
power-up. (1) Check battery polarity.
(2) Dead battery.
BAT Annunciator. (1) Low battery voltage, install a new
battery. If problem persists, con-
sult factory.
Display reads OPEN. (1) No thermocouple, RTD or thermis-
tor is plugged into the meter input.
Display reads E1 momentarily. (1) This indicates that an invalid key-
pad entry has been made. Review
keystroke sequence, or consult
manual for input instructions.
Display reads E2 momentarily. (1) Attempt made to activate non-
installed ramp function. NOTE:
RAMP Function enabled on
Models CL25 and CL27 only.
Display reads HI. (1) Meter-mode input-temperature
exceeds rating of selected sensor.
(2) Calibrator-mode keypad-entry
exceeds rating of sensor type.
Display reads LO. (1) Meter-mode input-temperature too
low for accurate measurement.
(2) Calibrator-mode keypad-entry too
low for accurate simulation.
2. INITIAL TURN ON
Turn on the instrument by depressing the ON-OFF keyswitch once (Figure
2). At power-up, the unit first performs a display test. All segments and
annunciators of the liquid crystal (LCD) are momentarily turned on for visual
confirmation by the user (Figure 3).
NOTE: In case of missing or poor-contrast segments, contact
factory.
11

If the unit is turning on for the first time after a new battery is installed, it will
automatically default to the METER mode (ie. temperature measurement
operation). It also defaults to K-type thermocouples, and °F readings with
0.1° resolution. The corresponding LCD annunciators are enabled:
12
Figure 3. Display Test
Figure 2. Keypad

METER: (unit functioning as a thermometer)
K: (K-type thermocouple)
°F: (Fahrenheit readings)
OPR: (Instrument is operational)
If no input thermocouple is connected to the unit at this time, the numeric
segments will indicate "OPEN".
Plugging a thermocouple into the meter jack (connector T2, on the top right
side) will give actual thermocouple temperature readings.
NOTE: To obtain full accuracy, allow 1-2 minutes after connect-
ing a thermocouple plug, for thermal setting.
If the instrument is to be used as a thermometer or ohmmeter, refer to the
Meter Mode Operation section for detailed instructions. For use as a tem-
perature-calibrator or ohms simulator, refer to Calibrator Mode Operation.
3. METER MODE OPERATION (Thermocouples)
Set-Up:
1. Turn on instrument by depressing the ON/OFF key.
2. Check that the BAT annunciator turns off following the power-up LCD test.
If it does not turn off, less than 10% of battery remains. Refer to Battery
Installation/Replacement instructions.
3. If the meter is already in the METER mode, the METER annunciator will
be on. Otherwise the calibrator mode is enabled and the CALIB annunci-
ator is on. Depress the METER key to return to meter mode.
4. Connect an input thermocouple (TC) to connector T2. Select the appro-
priate TC Type with the select-key. A display annunciator will indicate the
selected TC-type.
NOTE: Space and legibility constraints on the display preclude
the use of dedicated annunciators for the less common tungsten-
rhenium thermocouple types (G, C & D). Instead, these types are
annunciated momentarily on the alpha-numeric display when first
selected. Both T and R annunciators remain on to indicate a
Tungsten-Rhenium selection. To recall the actual G, C, D selec-
tion, turn the unit off, then on again for another momentary read-
out.
5. Select temperature scale with °F/°C key. The corresponding annunciator
is enabled.
13

14
Figure 4. 2-Wire Resistance Measurement
Figure 5. 3-Wire Resistance Measurement
6. Select display resolution with 0.1°/1° key.
NOTE: Set-up is retained during power-off.
Hold:
Meter readings can be put on hold at any time by depressing the HOLD key.
At this time, the HOLD annunciator turns on, the reading is frozen, and all
keys (except ON/OFF and HOLD) are locked out. Depress the HOLD key
again to return to real-time readings, and re-enable the keypad.
4. METER MODE OPERATION (RTD, Thermistor & Ohms)
Set-Up:
1. Connect a sensor or unknown resistance to the instrument as shown in
Figures 4, 5, or 6.
The 2-wire configuration is simplest, but includes lead-wire resistance in
the measurement. 2-wire measurements are generally limited to high
resistance sensors (e.g. 1000-ohm RTDs, 2252-ohm thermistors).

15
Lead resistance errors are compensated for in 3-wire configurations.
However full compensation requires equal resistance in each lead. This
configuration is common with 100-ohm RTDs.
In 4-wire configurations, accuracy is unaffected by lead resistance, and
resistance differences between leads.
NOTE: These instruments measure input voltages on all 4 termi-
nals, and are able to distinguish between 2-4 and 3-wire hookups.
Switching between these measurement modes is automatic.
2. Set instrument to METER mode.
3. Use the sensor-select key to set the instrument to the appropriate func-
tion and range.
NOTE: Due to limited display area, 100Ωand 1000ΩRTD's are
indicated on the display by a momentary readout of "RTD-100"
(or "RTD-1000") when first selected.
Thermistors are identified by a momentary alpha-numeric readout
of "Y-400" (signifying YSI Series-400 type thermistor).
Any of these readouts can be recalled by turning the unit off and
back on.
5. DATA LOGGING AND RECALL
Operating as a meter, the unit can save and recall up to 10 readings (each
with independent parameters: eg. °F/°C, TC-type and resolution) in random
access memory.
Figure 6. 4-Wire Resistance Measurement
WHT
BLK
GRN
RED

To Save Readings:
1. While in the METER OPR mode, depress the STORE key. Note that the
OPR annunciator is replaced by STO.
2. Next depress one of the memory location numbers (keys 0, 1, . . ., 9). The
corresponding memory annunciator turns on and the meter returns
momentarily to the OPR mode, displaying thermocouple temperature.
eg. STORE 7
NOTES:
•The enabled location annunciator indicates that the meter read-
ing at the instant that the location number key was hit, was
stored in memory.
• When data is stored in a location already filed with data, the
new data replaces the old.
• Stored readings are retained during power-off.
To Recall Readings:
1. While in the METER OPR mode, readings stored earlier can be displayed
by first depressing the RECALL key. Note that the OPR annunciator is
replaced by RCL, and all memory location annunciators are blanked.
2. Next depress the keypad number corresponding to the desired location.
Note that the annunciator for this location turns on, and the memory con-
tents are displayed.
3. Several stored readings can be randomly recalled by a key sequence
such as:
16
Figure 7.
T1
Calibrator
(output)
T2
Thermometer
(input)

eg. RECALL 3
eg. RECALL 5
eg. RECALL 2
eg. etc.
4. To return the meter to the operate mode, depress OPR after recalling the
last reading. All active location annunciators will turn on again, together
with the OPR annunciator.
NOTE: Recalling data from unused (ie, empty) locations will give
a zero reading.
To Erase Data Locations (Meter Mode):
1. Individual data locations can be erased by recalling the location to be
cleared, followed by a CLEAR key input. Note that the annunciator for the
cleared location is turned off, and the meter returns to OPR.
eg. RECALL 3
eg. CLEAR
NOTES: There is no need to clear a location if new data is ready
for saving in this location. Just STORE the new data. It will write
over and delete the old.
6. CALIBRATOR MODE OPERATION (Thermocouples)
Set-Up:
1. Turn on the instrument by depressing the ON/OFF key.
2. Check that the BAT annunciator turns off after display check. If not, refer
to Battery Installation/Replacement instructions.
3. When operating as a calibrator, the display indicates CALIB. Should the
instrument be in the METER mode, hit the CALIB key to change to the cal-
ibrator function.
4. Select the thermocouple type that will be used.
NOTE: Space and legibility constraints on the display preclude
the use of dedicated annunciators for the less common tungsten-
rhenium thermocouple types (G, C, & D). Instead, these types are
annunciated momentarily on the alpha-numeric display when first
selected. Both T and R annunciators remain on to indicate a
Tungsten-Rhenium selection. To recall the actual G, C, D selec-
tion, turn the unit off, then on again for another momentary read-
out.
5. Select the desired temperature scale (°F/°C key).
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6. Select the resolution desired (0.1°/1° key).
NOTE: With 1° resolution, one less key stroke will be required to
enter calibrator output temperatures via the keypad.
7. The unit accepts numeric inputs by first changing the keypad to its num-
ber-entry mode (NUM) by depressing the CHANGE/ENTER key once.
The numeric display will flash, the OPR annunciator will turn off, and the
NUM annunciator will turn on. Key in desired temperature value, most sig-
nificant digit first. After the desired temperature value is keyed in, hit
CHANGE//ENTER to return to OPR mode.
7. To enter a value of 212° with 0.1° resolution, the following keystrokes are
used: CHANGE/ENTER, 2, 1, 2, 0, CHANGE/ENTER
NOTES:
•Invalid numeric entries (eg. a temperature beyond the span of
the selected TC type) will cause a corresponding error code to
be displayed.
• To enter negative (ie. minus) temperatures, hit the –0 key first
when in the NUM mode. The first hit on this key enters the neg-
ative sign. Subsequent hits enter zeros.
• To correct a numeric entry while in the NUM mode, hit the
CHANGE/ENTER key twice. This will return number entry to
the beginning of a new number.
• To return the calibrator output to 0° while in the OPR mode, hit
the CLEAR key.
• The unit can be used as a convenient °F to °C or °C to °F cal-
culator.
For example, to convert 77°F to a Celsius reading, go to the CALIB OPR
mode, enter the reading to be converted, and change scale.
eg. °F
eg. CHANGE/ENTER
eg. 77
eg. CHANGE/ENTER
eg. °C (Display reads 25°C)
7. CALIBRATOR MODE OPERATION (RTD, Thermistor & Ohms)
Set-Up:
1. Connect measurement equipment under test (eg. RTD thermometer,
ohmmeter, etc.) to the instrument as shown in Figures 8, 9, or 10.