Emerson Rosemount 644h, Reference Manual

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Reference Manual
00809-0100-4728, Rev HA
December 2002
Models 644H and 644R
1-4
Figure 1-1 provides an example of the relationship between transmitter
housing temperature rise and extension length.
Figure 1-1. Model 644H
Transmitter Connection Head
Temperature Rise vs. Extension
Length
Example
The transmitter specification limit is 85 °C. If the ambient temperature is 55 °C
and the process temperature to be measured is 800 °C, the maximum
permissible connection head temperature rise is the transmitter specification
limit minus the ambient temperature (moves 85 to 55 °C), or 30 °C.
In this case, an extension of 100 mm meets this requirement, but 125 mm
provides a margin of 8 °C, thereby reducing any temperature effects in the
transmitter.
RETURN OF MATERIALS
To expedite the return process in North America, call the Emerson Process
Management National Response Center toll-free at 800-654-7768. This
center, available 24 hours a day, will assist you with any needed information
or materials.
The center will ask for the following information:
• Product model
• Serial numbers
• The last process material to which the product was exposed
The center will provide
• A Return Material Authorization (RMA) number
• Instructions and procedures that are necessary to return goods that
were exposed to hazardous substances
For other locations, please contact a Emerson Process Management sales
representative.
NOTE
If a hazardous substance is identified, a Material Safety Data Sheet (MSDS),
required by law to be available to people exposed to specific hazardous
substances, must be included with the returned materials.
60
50
40
30
20
10
0
75 100 125 150 175 200 225
Te
mp
er
a
ture R
ise Abo
ve Am
bien
t
Extension Length (mm)
81
5 °
C
Proc
ess
Tempe
rature
54
0 °
C
Proce
ss
Temperature
250 °C
Process Temperature
3044
-0123
A