917X Display Temperature Offset

1
917X Display Temperature Offset

• Michael Chai
• Levi Haupt
• Chris Roberts

2
Introduction

• Problem
• Depending on selection of probe temperature
  difference between reference probe and display is
  generated.
• Objective
• Develop method to reduce temperature difference
  between reference probe and display probe.

3
Thermal Circuit
R1 Conduction through block   0.0889
K of Block 175
DdisplaytoIDblock 0.000508
R2 Convection of air gap between block and insert Convection of air gap between block and insert 4.23E-05
Thermal Conductivity of air (Kair)
DIDblocktoODinsert 0.0022098
R3 Conduction through insert   0.386715
K of Insert 175
DODinsertIDinsert 0.0022098
R4 Convection of air gap between insert and probe Convection of air gap between insert and probe 4.23E-05
Thermal Conductivity of air (Kair) 2.75E00
DIisnertODprobe 0.00254
R5 Conduction through probe   0.00635
K of Probe 25
DODprobeIDprobe 0.000254
R6 Convection of air gap inside probe   4.23E-05
Thermal Conductivity of air (Kair) 2.75E00
DIDprobePlatinum 0.0000254
RTotal     4.82E-01
qTotal     1
TDisplay     149.5189
Reference Probe
Display Probe
4
Surface Contact Calculator
Link to Calculator http//cocoe.sourceforge.net/ C
lick on The Project Page
5
Results

• Problem is too complex to use simplified thermal
  circuit (.5 C difference)
• Experimentation needed for accurate results
  (Calibration)
• Recommended Solution
• Calibration for each insert orientation