AccuMac AM1760 User manual

Rev. 201609V3
AM1760/1762 Secondary Standard
Platinum Resistance Thermometer
User’s Guide
Please download the latest version at www.accumac.com

AM1760/1762 Secondary SPRT User’s Guide
Rev. 201609V3 1/10
Table of Contents
Before you start ---- Warnings & Cautions ........................................................................ 2
1 Introduction ................................................................................................................ 3
1.1 Main Application ................................................................................................ 3
1.2 Main Features ..................................................................................................... 3
1.3 Calibrations ......................................................................................................... 3
2 Specifications .............................................................................................................. 4
2.1 Specifications ...................................................................................................... 4
3 General Operations .................................................................................................... 5
3.1 Connecting to the readout device ........................................................................ 5
3.2 Drive Current ...................................................................................................... 5
3.3 Stability of Readings ........................................................................................... 5
3.4 Immersion Requirements .................................................................................... 5
3.5 Thermal EMF ...................................................................................................... 6
3.6 Over heating ........................................................................................................ 6
4 Care and Handling Guidelines ................................................................................... 7
5 Troubleshooting .......................................................................................................... 8
5.1 Troubleshooting .................................................................................................. 8
5.2 Problem Causes and Solutions ............................................................................ 8
6 Limited Warranty & Limitation of Liability ............................................................... 9

AM1760/1762 Secondary SPRT User’s Guide
Rev. 201609V3 2/10
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.

AM1760/1762 Secondary SPRT User’s Guide
Rev. 201609V3 3/10
1 Introduction
1.1 Main Application
AM1760/1762 Secondary Standard Platinum Resistance Thermometer
(SPRT) interpolates temperature in the range from -200 °C to 670 °C
on the International Temperature Scale of 1990 (ITS-90). It works
together with a readout device to measure temperature or change of
temperature. It is designed as a secondary standard thermometer to
calibrate other thermometers and to measure temperature precisely in
metrology labs.
1.2 Main Features
 High accuracy: ±0.006 ºC at 0.01 °C
 Temperature range: : -200 °C to 670 °C
 Rtpw Drift < 4 mK after 100 hours at 661 °C
1.3 Calibrations
As a temperature reference standard, each SPRT must be calibrated.
Manufacturer recommends calibration interval to be one year. 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.

AM1760/1762 Secondary SPRT User’s Guide
Rev. 201609V3 4/10
2 Specifications
2.1 Specifications
Temperature Range -200 °C to 670 °C
Resistance at 0 °C 1760 - Nominal 100 Ω
1762 – Nominal 25 Ω
Temperature Coefficient 0.003925 Ω/ Ω/°C
Accuracy ±0.007 °C at -196 °C
±0.006 °C at 0.01 °C
±0.015 °C at 420 °C
±0.025 °C at 661 °C
Drift* ±0.004 °C at TPW after 100 hours at 661 °C
Short Term Stability ±0.002 °C
Thermal Shock ±0.002 °C after 10 times thermal cycles from minimum to
maximum temperatures
Self-heating 0.0015 °C at 1 mA current
Response Time 9 seconds for 63% response to step change in water moving
at 3 feet per second
Measurement Current 1 mA
Sensor Length 42 mm
Sensor Location 5 mm from tip
Insulation Resistance >1000 MΩ at room temperature
Sheath Material Inconel
tm
Dimension 1760/1762-12: 0.25 inch X 12 inch (6.35 mm X 305 mm)
1760/1762-20: 0.25inch X 20 inch (6.35 mm X 500 mm)
External Leads Teflon
tm
– insulated copper wire, 4 leads, 2.5 meters
Handle Dimension 15 mm (OD) X 65 mm (L)
Handle Temperature
Range**
-50 °C to 180 °C
Optional Calibration NIST traceable calibration and data available per request:
Ordering # 5007
*Long-term drift rate is for reference only. It could be affected by such facts as handling, application, and maintenance, etc.
**Handle temperature outside this range will cause damage to the probe.

AM1760/1762 Secondary SPRT User’s Guide
Rev. 201609V3 5/10
3 General Operations
3.1 Connecting to the readout device
The AM1760/1762 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.
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 SPRT 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
Figure1
Black Blue
White Red

AM1760/1762 Secondary SPRT User’s Guide
Rev. 201609V3 6/10
gradually until the readings have significant changes after
stabilization.
Do not submerge SPRT 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 AM1760/1762 SPRT is sealed inside an
Inconel
tm
sheath to ensure the best stability and repeatability. The seal
can be breached if the SPRT is over heated for an extended period of
time.

AM1760/1762 Secondary SPRT User’s Guide
Rev. 201609V3 7/10
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.

AM1760/1762 Secondary SPRT User’s Guide
Rev. 201609V3 8/10
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.

AM1760/1762 Secondary SPRT User’s Guide
Rev. 201609V3 9/10
6 Limited Warranty & Limitation of Liability
The material contained in this document is provided “as is,” and is
subject to being changed, without notice, in future editions. AccuMac
shall not be liable for errors or for incidental or consequential
damages in connection with the furnishing, use, or performance of this
document or of any information contained herein. Should AccuMac
and the user have a separate written agreement with warranty terms
covering the material in this document that conflict with these terms,
the warranty terms in the separate agreement shall control.
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: [phone]
Email: [e-mail]