28022 Parallax Inc, 28022 Datasheet - Page 3

• Manufacturer Part Number: 28022
• Description: KIT DS2760 THERMOCOUPLE
• Manufacturer: Parallax Inc

Specifications of 28022

• Lead Free Status: Contains lead
• Accessory Type: Thermocouple Kit
• For Use With/related Products: BASIC Stamp® Modules
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

BASIC Stamp Application
The following BASIC Stamp application will run on either the BS2p or BS2pe and demonstrates how easy
measuring wide-range temperatures can be when using the DS2760 Thermocouple Module.
Stamps will require a Serial-to-1-Wire protocol converter, as well as code to manage the large tables
across program slots, and are not covered in this document.
A little background: When two dissimilar metal wires are joined, a voltage will be developed across the
open end that is proportional to the temperature difference between the joined and open ends. This
effect was discovered by Thomas Seebeck in 1821. Through empirical testing, voltage tables have been
established that correspond to the thermocouple junction temperature. These tables, however, use a
cold junction (voltage measurement point) reference of zero degrees Celsius, forcing electronic devices to
employ cold junction compensation.
Using the DS2760 we can measure the Seebeck voltage from the thermocouple with a resolution of
15.625 microvolts, then measure the cold junction temperature with a resolution of 0.125 degrees
Celsius.
compensation voltage. This is combined with the Seebeck voltage and, using a modified binary search
algorithm, we can determine the compensated temperature from the thermocouple data table.
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' -----[ Program Description ]---------------------------------------------
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' This program lets a BS2p or BS2pe read the temperature from the Parallax
' DS2760 thermocouple module.
' and temperature display is via the DEBUG window.
' -----[ Revision History ]------------------------------------------------
' -----[ I/O Definitions ]-------------------------------------------------
OW
Parallax, Inc. • DS2760 Thermocouple Kit (#28022) • 01/2004
File...... DS2760TC_Demo.BPE
Purpose... Thermocouple temperature measurement using the DS2760
Author.... Parallax, Inc.
E-mail.... [e-mail]
Started...
Updated... 19 JAN 2004
{$STAMP BS2pe, KTablePos.BPE, JTablePos.BPE, TTablePos.BPE}
{$PBASIC 2.5}
A simple table look-up using the cold junction temperature will give us the cold junction
PIN
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(Copyright 2004, All Rights Reserved)
User input of thermocouple type (K, J, or T)
' 1-Wire buss pin
Other
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