AccuMac AM1850 User manual

AM1860/1850 Standard Platinum
Resistance Thermometer User’s
Guide

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User’s Guide
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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

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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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1 Introduction
1.1 Main Application
AM1860/1850 Standard Platinum Resistance Thermometer (SPRT)
is an interpolating instrument converting temperature to resistance.
It works together with readout device to measure temperature or
change of temperature. It has wide applications for dry-wells or
temperature baths.
1.2 Main Features
Extreme low drift rate
Metal sheathed
Great reference thermometer for dry block calibrator
1.3 Calibrations
It is recommended to calibrate this SPRT 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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2 Specifications
2.1 Specifications
Temperature Range
1850: -200°C to 500°C
1860: -200°C to 670°C
Rtpw
Nominal 25 Ω or nominal 100 Ω
Resistance Ratio
W(Ga)>=1.11807
W(Hg)<=0.844235
Drift at 0.01°C*
1850 ΔR(0.01°C ) <0.002 °C/100 hours at 500°C
ΔR(0.01°C ) <0.008 °C/year
1860 ΔR(0.01°C ) <0.003 °C/100 hours at 670°C
ΔR(0.01°C ) <0.01 °C/year
Repeatability
±0.0015 °C
Thermal Shock
±0.0015 °C after 10 times thermal cycles from minimum to
maximum temperatures
Self-heating
0.0015 °C at 1 mA current
Measurement Current
1 mA
Sensor Length
42 mm
Insulation Resistance
>1000 MΩ at room temperature
Sheath Material
InconelTM
Dimension
1850: 6.35 mm (OD) X 480 mm (L)
1860: 6.35 mm (OD) X 500 mm (L)
External Leads
Insulated copper wire, 4 leads, 2.5 meters
Termination
Gold-plated Spade
Handle Dimension
21mm (OD) X 80 mm (L)
Calibration
Not included

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3 General Operations
3.1 Connecting to the readout device
The AM1860/1850 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 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
Figure1
Blue
Yellow
White
Red

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minimize the error, appropriate immersion depths are required. A
practical way to determine the minimum immersion depths is to
change the depth 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 this SPRT is sealed inside an Inconeltm 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.

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4 Care and Handling Guidelines
1. DO NOT subject the SPRT to any physical shocks and
vibrations.
a. When not using the SPRT, 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 SPRT, 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 SPRT move up and down
smoothly.
2. DO NOT subject the SPRT to any contaminations.
a. Keep the SPRT as clean as possible. Avoid
contaminations as much as possible.
3. DO NOT over heat.
a. Do not use SPRT above the manufacture specified
temperature range.
b. Do not expose the SPRT handle and lead wires to
extreme temperatures.

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5 Troubleshooting
5.1 Troubleshooting
If the SPRT 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 SPRT available.
5.2 Problem Causes and Solutions
a. R0/Rtpw becomes higher significantly. This is likely caused
by mechanical shocks. The SPRT should be annealed to
release the stress of platinum wires and to recover R0/Rtpw
value. Measure R0/Rtpw of the SPRT 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
SPRT may be damaged.

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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:
1490 S Price Rd STE 211 C
Chandler, AZ 85286
USA
Tel: [phone]
Email: [e-mail]