Fluke 80T-150U User manual

PN 778134 February 1986 Rev. 8, 7/00
1985, 1995, 1996, 2000 Fluke Corporation. All rights reserved. Printed in USA All product names are trademarks of their respective companies.
Introduction
The Model 80T-150U Universal Temperature Probe is a self-
contained temperature-to voltage converter. The probe is designed
to provide a direct temperature reading when it is connected to any
high impedance DMM that is capable of 1 mV resolution and at
least a 300-count full scale readout capability. Output is l mV per
degree (Celsius or Fahrenheit). Two switch-selected temperature
output scalings are provided: -50 to +150°C or -58 to +302°F. The
probe will stand off 60V dc or 30V ac rms (42.4V peak).
The unit is housed in two separate but attached assemblies: a
temperature probe and a temperature-to-voltage converter. The
probe contains the temperature-sensing element and is electrically
connected to the temperature-to-voltage converter through a 46-
inch shielded cable. A three-position switch on the converter acts
as a power switch and is used for selecting Celsius or Fahrenheit
scaling for the output. Two banana plugs with standard 0.75-inch
spacing are provided for connecting the 80T-150U to the DMM.
Operating power for the 80T-150U is derived from a standard 9V
battery. Typically, an alkaline battery provides more than 1600
hours of continuous operation before replacement is necessary. An
OFF switch is provided on the temperature-to-voltage converter to
allow battery conservation when the unit is not in use. In addition,
the OFF position of the power switch allows the battery condition to
be determined via the external DMM.
Temperature is measured by exposing the probe tip directly to the
material to be measured (non-corrosive liquid, gas, or solid). A
direct temperature reading is displayed on the DMM.
Specifications
The 80T-150U will achieve rated accuracy when it is used with any
0.25% DMM that has an input impedance of ≥1 MΩ.
Electrical
Measurement Range: (See Probe Limitations)
-50 to +150 degrees Celsius
-58 to +302 degrees Fahrenheit
Accuracy: (Applies for one year after purchase or calibration)
AMBIENT °C ACCURACY
+15 to +35°C±1°C from 0 to +100°C,
decreasing linearly to ±3°C at -50
and +150°C
0 to 15°C and ±2°C from 0 to +100°C,
+35 to +50°C decreasing linearly to ±4°C at
-50 and +150°C
AMBIENT °F ACCURACY
+59 to +95°F±1.8°F from +32 to +212°F,
decreasing linearly to ±5.4°F at
-58 and 302°F
+32 to +59 °F and ±3.6°F from +32 to +212°F,
+95 to +122 °F decreasing linearly to ±7.2 °F
at -58 and 302°F
Sensitivity (80T-150U output): 1 mV dc / °C or °F
Voltage Standoff: 60V dc or 30V ac rms (42.4V peak)
Settling Time: 5.5 seconds to settle within 2°for a 50°change
RF Field: Exposure to an RF field interferes significantly with this
module’s capacity to accurately measure temperature. The
interference is temporary and the module suffers no harm when
exposed to an RF field of 3 V/m. Accurate temperature
measurement capability is completely restored when the module is
removed from the RF field.
Common sources of RF fields are handheld two-way radios and
cellular telephones. If such a source is suspected of interfering with
this module, either turn off the transmitter or increase the
separation between the transmitter and the module.
Environmental
Ambient Operating Range for Temperature Module: 0 to +50°C
(+32 to +122°F)
Maximum Temperature Probe Body and Cable: +70°C (160°F)
See Probe Limitations
Minimum Temperature Probe Body and Cable:
Minimum Operating Temperature for Cable: -12°C (10°F)
Minimum Operating Temperature for Probe Body: -40°C
(-40°F) See Probe Limitations
Storage Temperature for Unit: -40 to +70°C (-40 to +160°F)
Humidity: 0% to 90% (0°C to 35°C)
0% to 70% (35°C to 50°C) (noncondensing)
Altitude: Operating: ≤10,000 feet
Storage: ≤50,000 feet
Application Force: 15 pounds maximum (probe tip to measured
surface)
General
Weight: 5.7 ounces, 161.5 grams
Overall Length: 53.8 inches, 1.36 meters
Battery: Standard 9V battery (NEDA #1604,6F22,006P)
Battery Life: 1600+ hours, typical (Alkaline Battery), 6.5V
minimum
Output Termination: Standard 0.75-inch spaced double banana
plug
Probe Material: Glass-filled valox
Probe Size: 0.6" maximum diameter
Tip Material: Aluminum
Tip Size: 0/07" to 0.08" diameter, 30% convexed
Operating Notes
The following paragraphs are intended to familiarize the operator
with the 80T-150U. The operator should read these paragraphs
before attempting to operate the probe.
Probe Limitations
The 80T-150U probe is constructed of a highly durable plastic and
is suitable for measuring the temperature of liquids, gases, and
solid surfaces up to 150°C. When measuring temperature, observe
the following precautions to prevent damage to the probe:
1. Do not expose the probe end (probe tip plus about 2 inches of
the probe body) to temperatures exceeding +150°C (302°F).
The remainder of the probe body should not be exposed to
temperatures above +70°C (160°F).
®
80T-150U
Universal Temperature Probe
Instruction Sheet

2. Do not expose the probe end (probe tip plus about 2 inches of
the probe body) to temperatures below -50°C (-58°F). The
remainder of the probe body should not be exposed to
temperatures below -40°C (-40°F).
3. For liquid measurements, recommended applications range
from water, lubricants, and fuels to most solvents. Liquids as
shallow as 1/2 inch can be measured since the temperature
sensor is in the probe tip.
Warning
To avoid electrical shock, do not use this
instrument when voltages exceeding 60V dc or 30V
ac rms (42.4V peak ) are present. The probe tip is
electrically connected to the output terminals.
Caution
Long-term exposure of the probe to corrosive
environments will result in pitting and deterioration
of the aluminum probe tip.
Error Sources
When the probe tip is applied to a solid surface, it draws or sinks
heat from the surface. Therefore, if the measured surface has a
low mass (e.g., a transistor case), the indicated temperature may
be lower than the actual temperature.
Similarly, a steady-state error or gradient exists between the
measured surface and the sensing device in the probe tip. This is
due to the flow of heat from the measurement surface to the probe
body. The effect of the steady-state error increases as the
differential between ambient and surface temperature increases.
To determine the actual surface temperature of a device, both the
heat-sinking and steady-state errors must be considered. The
correction curve given in Figure 1 approximates the effect of both
error sources on TO-3, TO-5, and TO-18 transistor cases.
RF signals applied to the 80T-150U probe tip can also cause errors
in temperature measurement. Figure 2 defines the rf signal limits
that can be tolerated without degrading measurement accuracy.
F1.eps
Figure 1. Initial Case Temperature Above Ambient vs
Meter Reading Above Ambient
F2.eps
Figure 2. Maximum Signal RF Limits (Vrms) at Probe Tip
Operation
Use the following procedure to operate the 80T-150U probe:
1. Connect the banana plugs on the 80T-150U to the input
terminals of a high impedance DMM. Observe polarity.
2. Select a dc voltage range that will provide at least 1 mV
resolution (1 mV/degree) and a full scale readout that will
encompass the expected temperature. The 2V range of a 3
1/2-digit DMM is adequate. Ignore readings of less than 1°
when a more sensitive DMM is used.
3. Set the 80T-150U power switch to °C or °F, and energize the
DMM.
4. Firmly touch the probe tip to the surface to be measured, or
expose it to a liquid or gas. The DMM will display the
temperature in degrees. Vary the probe angle and pressure
when measuring solid surface temperatures. The highest
stabilized reading will be the most accurate. (See the following
measuring technique.) Caution
The force exerted on the probe tip should not
exceed 15 pounds.
Measuring Technique
Here are some suggestions for improving the accuracy of your
temperature measurements:
1. When measuring higher than ambient temperatures, adjust
the connection between the probe and the surface until you
get the highest temperature reading.
2. When measuring lower than ambient temperatures, adjust the
connection between the probe and the surface until you get
the lowest temperature reading.
3. When measuring near ambient temperatures, make the
reading when the multimeter readout is most stable.
Theory Of Operation
The Model 80T-150U uses the negative temperature coefficient of
a semiconductor (P-N) junction to measure temperature. The PN
junction is thermally integrated into the probe tip and comprises
one leg of a bridge circuit as shown in the simplified circuit diagram
of Figure 3. One 9V battery is used to power both the bridge circuit
and operational amplifier U1. Since the bridge must be balanced to
provide 0°C and 0°F indications, separate range or temperature
scale resistors R7 and R6 are included in the bridge circuit. When
R6 and R2 are shorted by S1, the °C scale is selected and the
bridge is calibrated by R3 to null at 0°C. Conversely, when S1 is
open, the 0°F scale is selected, and the bridge is calibrated by R2
to null at 0°F. Deviations above and below 0°provide a bridge
output of approximately 2.45 mV/°C.
Operational amplifier U1 is used to measure the bridge output and
scale it to a 1 mV/degree signal. Since the °C and the °F scale are
sloped differently, the scale for U1 must be matched with the scale
selected for the bridge circuit. Shorting resistors R15 and R18
selects the °C scale. Conversely, when S1 is open, the °F scale is
selected. Resistor R4 calibrates both scales.
The output voltage used to drive the external voltmeter is taken
from the output of U1 (P2) and the reference side of the bridge
(P1). Since U1 is operating as an inverting amplifier, its output is
used as the low input to the voltmeter. This enables the voltmeter
to display an increase in temperature as an increase in voltage.
General Maintenance
Access Information
The battery and the calibration pots are located on the interior of
the temperature-to-voltage converter assembly. Access to these
locations is accomplished by removing the screw from the bottom
side of the assembly and removing the top of the plastic box.

Battery Condition Test
1. Set the power switch to the OFF position.
2. Connect the 80T-150U to the DMM.
3. Set the DMM to the 200 or 400 mV dc range.
4. Read the battery test voltage on the DMM or test instrument.
For DMMs with 10 MΩinput impedance, a minimum reading
of 100 mV is acceptable. For test instruments with 1 MΩinput
impedances, such as ScopeMeter®, a minimum reading of 75
mV is acceptable, With these minimum readings,
approximately 100 hours of battery life remain.
Battery Replacement
Warning
To avoid electrical shock, remove the probe from
the measurement surface before opening the case.
Totally reassemble the instrument before
attempting to use it.
1. Set the power switch to the OFF position.
2. Disconnect the 80T-150U from the DMM.
3. Turn the 80T-150U so the power switch is facing down.
Remove the single screw located between the banana plugs.
4. Grasp one case half in each hand. Pull the two halves apart,
beginning at the end with the banana plugs.
5. Remove and replace the battery.
6. Reassemble the 80T-150U as follows. Mate the two case
halves at the end where the cable enters the case, then
"hinge" the two halves together. Replace the case screw,
being careful not to pinch the probe cable or battery wires.
U1
F3.eps
Figure 3. Simplified Circuit Diagram
Performance Test
Complete the calibration procedure without opening the
temperature-to-voltage converter assembly and without making
any calibration adjustments. Observe the readings given in
[brackets]. Other readings are for calibration only.
Calibration
The calibration cycle of one year is recommended to maintain the
unit within the specifications given earlier. The equipment required
for calibration is listed in the table following the calibration
procedure.
Note
Values given in brackets apply to the Performance
Test.
Perform the following steps to calibrate the 80T-150U:
1. Access the interior of the temperature-to-voltage converter by
removing the bottom case screw and separating the case
halves.
2. Connect the 80T-150U to a DVM with 10 µV resolution, and
select mV dc range.
3. Select the °C position of the switch. Immerse the probe tip 2
inches into a mercury thermometer monitored 0°C bath, and
allow 60 seconds for the readings to stabilize.
4. Adjust R3 (see Figure 4) to obtain the following reading:
0.00 ±0.05 mV dc [0 ±0.2 mV dc]
5. Select the °F position of the switch, and adjust R2 to obtain
the following reading:
32.0 ±0.1 mV dc [32.0 ±0.4 mV dc]
6. Select the °C position, and move the probe tip to a 70°C to
90°C bath and again allow the readings to stabilize.
7. Adjust R4 to obtain a DVM reading that agrees with the bath
temperature (BT) as monitored by a mercury thermometer.
°C BT ±0.05 mV dc [BT ±0.2 mV dc]
8. Select the °F position, and verify that the output is within ±4
mV dc of the bath thermometer reading. If necessary, change
the DVM range to obtain an on-scale reading.
9. Return the probe tip to the 0°C bath and check the output. If
readjustment is necessary, repeat steps 4 through 8 until
readings can be obtained without adjustment.
10. Set the 80T-150U switch to the OFF position, and remove the
80T-150U from the DVM.
11. Reassemble the 80T-150U.
12. The 80T-150U is now calibrated.
Probe Replacement
A probe kit (80T-150-7001K, PN 431023) is available for replacing
damaged or defective probes. The kit includes a probe and cable
assembly and an installation and calibration instruction sheet.
List Of Replaceable Parts
A schematic of the 80T-150U is shown in Figure 4. A list of
replaceable parts is shown in Figure 5. When ordering parts,
provide the description, Fluke part number, and the quantity
required.
Test Equipment Requirements
Instrument Type Minimum Use Specifications Recommended Model
Mercury Thermometer 0.1°C Resolution Princo Model SAMA-CP45
Dewar Flask and Cap 1-Pint Capacity (for Ice Bath) Thermos Bottle
Metal or Glass Container 1-Pint Capacity Suitable for Boiling Water
Digital Voltmeter 100 mV Range with 10 µV Resolution
1000 mV Range with 100 µVFluke Model 8840A
For application or operation assistance or information on Fluke products, call:
800-44-FLUKE (800-443-5853) in U.S.A. and Canada, 31 40 267-8200 in Europe, 206-356-5500 from other countries
Fluke Corporation Fluke Europe B.V.
P.O. Box 9090 P.O. Box 1186
Everett WA 98206-9090 5602 B.D. Eindhoven
USA The Netherlands

80T-150U-4011
Sensing Probe and Cable Assembly
White
Black
F4.eps
Figure 4. 80T-150U Temperature Probe Schematic
Replaceable Parts
5HI'HV 31 'HVFULSWLRQ
BT1 738179 80TK-8011
,
CONNECTOR
,
BATTERY
C1 C3-C7 106146 CAPACITOR,SMR,CAP,CER,0.01UF,+-10%,50V,X7R,0805
P1 P2 736033 80TK-8009,PLUG,BANANA
Q1 Q2 820910 PNP,MMBT5087,SMR,TRANSISTOR,SI,PNP,50V,225MW,SOT-23
R11 928903 RESISTOR,SMR,RES,CERM,464K,+-1%,0.1W,100PPM,0805
R12 928866 RESISTOR,SMR,RES,CERM,100K,+-1%,0.1W,100PPM,0805
R14 802733 RESISTOR,SMR,RES,MF,196K,+-0.1%,0.1W,50PPM,0805
R15 802741 RESISTOR,SMR,RES,MF,6.65K,+-0.1%,0.1W,50PPM,0805
R16 783274 RESISTOR,SMR,RES,CERM,10M,+-5%,.125W,400PPM,1206
R17 642329 RESISTOR,SMR,RES,CERM,34.8K,+-1%,.063W,100PPM,0603
R18 1541369 RESISTOR,METAL FILM,150K,+-0.1%,0.1W,25PPM,0805,TAPE
R2 802758 RESISTOR,SMR,RES,VAR,CERM,2K,+-20%,0.25W
R20 802642 RESISTOR,SMR,RES,CERM,2.4M,+-5%,0.1W,400PPM,0805
R21 928754 RESISTOR,SMR,RES,CERM,2.43K,+-1%,0.1W,100PPM,0805
R22 806240 RESISTOR,SMR,RES,CERM,1.2M,+-5%,.125W,200PPM,1206
R3 912493 RESISTOR,SMR,RES,VAR,CERM,100K,+-25%
R4 802766 RESISTOR,SMR,RES,VAR,CERM,50K,+-20%,0.25W
R5 R10 R13 876016 RESISTOR,SMR,RES,CERM,8.87K,+-1%,.125W,100PPM,1206
R6 642303 RESISTOR,SMR,RES,CERM,3.83K,+-1%,.063W,100PPM,0603
R7 643954 RESISTOR,SMR,RES,MF,30.1K,+-0.1%,0.1W,25PPM,0805
R8 929906 RESISTOR,SMR,RES,CERM,36.5K,+-1%,.125W,100PPM,1206
R9 642220 RESISTOR,SMR,RES,CERM,15.4K,+-1%,.063W,100PPM,0603
S1 772301 SWITCH,SWITCH,SLIDE,3P3T,WITH DETENT
U1 802774 IC,OP AMP,LM4250C,BIPOLAR
VR1 929489 BIPOLAR 4041,SMR,IC,V REF,SHUNT,1.2 V,2%,150 PPM,SOT23
W2 682575 RESISTOR,R05A,RES JUMPER,0.02,0.25W
747501 SCREW,SCREW,PH,PO,STL,4-40,.250
431023 SENSING PROBE AND CABLE ASSY
172080 CABLE TIE
615549 CASE,BOTTOM
129882 SCREW,PHP,4-40X3/16
769034 CASE,TOP
735860 COVER,SWITCH
428441 SHOCK ABSORBER
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