AM1750 Secondary Reference
Platinum Resistance Thermometer
User’s Guide
Please download the latest version at www.accumac.com
Rev. 201609V3
AM1750 Secondary Reference PRT User’s Guide
Table of Contents
Before you start ---- Warnings & Cautions ........................................................................ 2
1 Introduction ................................................................................................................ 3
1.1
1.2
1.3
2 Specifications .............................................................................................................. 4
2.1
3 General Operations .................................................................................................... 5
3.1
3.2
3.3
3.4
3.5
3.6
4 Care and Handling Guidelines ................................................................................... 7
5 Troubleshooting .......................................................................................................... 8
5.1
5.2
6 Limited Warranty & Limitation of Liability ............................................................... 9
Main Application ................................................................................................ 3
Main Features ..................................................................................................... 3
Calibrations ......................................................................................................... 3
Specifications ...................................................................................................... 4
Connecting to the readout device ........................................................................ 5
Drive Current ...................................................................................................... 5
Stability of Readings ........................................................................................... 5
Immersion Requirements .................................................................................... 5
Thermal EMF ...................................................................................................... 6
Over heating ........................................................................................................ 6
Troubleshooting .................................................................................................. 8
Problem Causes and Solutions ............................................................................ 8
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AM1750 Secondary Reference PRT User’s Guide
Before you start ---- Warnings & Cautions
Warnings: Follow these guidelines to avoid personal injury:
1. Only use this instrument in the manufacture specified
temperature range.
2. The handle of this instrument can become hot when it is used
to measure high temperatures for extended periods of time.
3. DO NOT submerge PRT handle when taking measurement.
4. DO NOT use this instrument to measure the temperature of
any hazardous live component.
5. Follow all other safety guidelines listed in this user’s guide.
Cautions: Follow these guidelines to avoid possible damage to
the instrument:
1. Avoid mechanical shocks. DO NOT drop or slam the probe in
any way. This will cause damage to the probe internally and
affect its calibration and accuracy.
2. Read Section entitled “Care and Handling Guidelines” before
removing the PRT from the shipping box. Incorrect handling
can damage the PRT and void the warranty.
3. Keep the shipping container in case it is necessary to ship the
PRT. Incorrect packaging of the PRT for shipment can cause
irreparable damage.
4. Calibration equipment should only be used by trained
personnel.
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AM1750 Secondary Reference PRT User’s Guide
1 Introduction
1.1 Main Application
AM1750 Secondary Reference Platinum Resistance Thermometer
(PRT) is an interpolating instrument converting temperature to
resistance. It works together with a readout device to measure
temperature or change of temperature. It has wide applications for drywells or temperature baths.
1.2 Main Features
High accuracy: 0.015 ºC at 0.01 °C
Temperature range: : -200 °C to 670 °C
Durable and shock resistance
1.3 Calibrations
It is recommended to calibrate this PRT annually over the full
temperature range. In between annual calibrations, user can check the
drift rate by comparing Rtpw against the last calibration results. Refer
to specifications section for normal drift rate.
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AM1750 Secondary Reference PRT User’s Guide
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2 Specifications
2.1 Specifications
Temperature Range
Resistance at 0 °C
Temperature Coefficient
Accuracy
Drift
Short Term Stability
Thermal Shock
Hysteresis
Self-heating
Response Time
Measurement Current
Sensor Length
Sensor Location
Insulation Resistance
Sheath Material
Dimension
External Leads
Handle Dimension
Handle Temperature Range*
Optional Calibration
*Handle temperature outside this range will cause damage to the probe.
1750-12: -200 °C to 670 °C
1750-20: -200 °C to 670 °C
Nominal 100 Ω
0.003925 Ω/ Ω/°C
±0.025 °C at -196 °C
±0.015 °C at 0.01 °C
±0.035 °C at 420 °C
±0.05 °C at 661 °C
±0.01 °C at TPW after 100 hours at 661 °C
±0.007 °C
±0.005 °C after 10 times thermal cycles from minimum to
maximum temperatures
<=0.005 °C
50 mW/°C
9 seconds for 63% response to step change in water moving
at 3 feet per second
0.5 mA or 1 mA
32 mm
5 mm from tip
>1000 MΩ at room temperature
Inconeltm
1750-12: 0.25 inch X 12 inch (6.35 mm X 305 mm)
1750-20: 0.25 inch X 20 inch (6.35 mm X 500 mm)
Teflon
15 mm (OD) X 65 mm (L)
-50 °C to 180 °C
NIST traceable calibration and data available per request,
Ordering # 5007
– insulated copper wire, 4 leads, 2.5 meters
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AM1750 Secondary Reference PRT User’s Guide
3 General Operations
3.1 Connecting to the readout device
The AM1750 is equipped with a four-wire cable (see Figure 1). Four
lead wires are used to cancel lead wire resistance. For best results, the
readout device should be equipped to handle four-terminal resistors.
The lead wires can be distinguished by insulation colors. Lead wire
pairs attached to each end of the sensor are identified by red/black and
white/blue insulation.
White Red
Black Blue
Figure1
3.2 Drive Current
AccuMac recommends 1mA as drive current to ensure the best
measurement.
3.3 Stability of Readings
To achieve the best accuracy, allow sufficient time for PRT to
stabilize before taking the readings.
3.4 Immersion Requirements
Stem effect can cause measurement errors due to heat lost or gained
by the sensing element through the thermometer stem. To minimize
the error, appropriate immersion depths are required. A practical way
to determine the minimum immersion depths is to change the depth
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AM1750 Secondary Reference PRT User’s Guide
gradually until the readings have significant changes after
stabilization.
Do not submerge PRT handle when taking measurement.
3.5 Thermal EMF
Each AccuMac PRT has gone through an annealing process and
stability test to minimize the thermal EMF, which is caused by either
impurities of sensing element or temperature differentials at lead wires
connection point.
3.6 Over Heating
The sensing element of AM1750 PRT is sealed inside an Inconeltm
sheath to ensure the best stability and repeatability. The seal can be
breached if the PRT is over heated for an extended period of time.
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AM1750 Secondary Reference PRT User’s Guide
4 Care and Handling Guidelines
1. DO NOT subject the PRT to any physical shocks and vibrations.
a. When not using the PRT, keep it in a place that’s not prone
to drop, slam, bang, vibration or other strong physical
contacts. Use a protective box or a carrying case whenever
possible.
b. When shipping the PRT, use protective box and other
protective packaging materials to minimize mechanical
shocks as much as possible.
c. When using dry blocks, make sure the well diameter is
appropriate to allow the PRT move up and down smoothly.
2. DO NOT subject the PRT to any contaminations.
a. Keep the PRT as clean as possible. Avoid contaminations
as much as possible.
3. DO NOT over heat.
a. Do not use PRT above the manufacture specified
temperature range.
b. Do not expose the PRT handle and lead wires to extreme
temperatures.
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AM1750 Secondary Reference PRT User’s Guide
5 Troubleshooting
5.1 Troubleshooting
If the PRT functions abnormally, it could be caused by several
possible problem conditions that are described in this section. Try the
solutions recommended and if the problems are still not solved,
contact manufacture for warranty or repair service. Be sure to have the
model number and serial number of your PRT available.
5.2 Problem Causes and Solutions
a. R0/Rtpw becomes higher significantly. This is likely caused by
mechanical shocks. The PRT should be annealed to release the
stress of platinum wires and to recover R0/Rtpw value. Measure
R0/Rtpw of the PRT after annealing to verify.
b. R0/Rtpw unstable during the measurement. This is likely caused
either by bad connections or sensor coils short. Check the
connections first and if the connections are good, the PRT may
be damaged.
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AM1750 Secondary Reference PRT User’s Guide
6 Limited Warranty & Limitation of Liability
Each product from AccuMac Corporation is warranted to be free from
defects in material and workmanship under normal use and service.
The warranty period is 1 year for the Platinum Resistance
Thermometer. The warranty period begins on the date of the shipment.
Parts, product repairs, and services are warranted for 90 days. The
warranty extends only to the original buyer or
end-user customer of an AccuMac authorized reseller. The warranty
will not extended to products that have been misused, altered,
neglected, or damaged by accident or abnormal conditions of
operation or handling.
To obtain warranty service, contact AccuMac Corporation at:
90 N William Dillard Drive C-107
Gilbert, AZ 85233
USA
Tel: (480) 634-0603
Email:
Rev. 201609V3 9/10
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