2-3
MOUNTING
The Model 244EH installs in a connection head or universal head
mounted directly on a sensor assembly, apart from a sensor assembly
using a universal head, or to a DIN rail using an optional mounting
clip. The Model 244ER mounts directly to a wall or to a DIN rail.
The Models 244EH and 244ER transmitters will operate within
specifications for ambient temperatures between –40 and 185 °F
(–40 and 85 °C).
In a direct mounting configuration using a Model 244EH transmitter,
process heat is transferred from the thermowell to the transmitter via
the connection head. If the expected connection head temperature is
near or beyond specification limits, consider the use of additional
thermowell lagging, an extension nipple, or a remote mounting
configuration to isolate the transmitter from excessive temperatures.
Figure 2-2 provides an example of the relationship between transmitter
housing temperature rise and extension length. Use Figure 2-2 as a
guide for determining adequate thermowell extension length.
Figure 2-2. Model 244EH 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
(85 –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.
304
4-
012
3A
60
50
40
30
20
10
0
75
100
125
150
175
200
225
T
e
m
p
erat
u
re
R
is
e
A
bo
ve
Ambien
t
(°C)
Extension Length (mm)
81
5
°C
Proc
ess
Temp
eratu
re
5
4
0
°C
Pr
oce
ss
Temperatu
re
250 °C
Process Temperature
