Direct Mount - Emerson Rosemount 702 Reference Manual

Rosemount 702
MOUNTING
Figure 3-1. 702 Transmitter
Connection Head Temperature
Rise vs. Extension Length

Direct Mount

3-2
The Rosemount 702 can be installed in one of two configurations: Direct
Mount, where the switch is connected directly to the 702 housing's conduit
entry, or Remote Mount, where the switch is mounted separate from the 702
housing, then connected to the 702 via conduit. Choose the installation
sequence that corresponds to the mounting configuration.
Figure 3-1 provides an example of the relationship between transmitter
housing temperature rise and extension length.
60 (108)
50 (90)
40 (72)
55
30 (54)
20 (36)
10 (18)
0
Example
The transmitter specification limit is 85 °C. If the ambient temperature is 55 °C
and the max process temperature to be measured is 815 °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 5" meets this requirement, but 6" provides an
additional margin of thermowell protection, thereby reducing risk of ambient
thermal damage.
The direct mount installation should not be used when installing with a
®
Swagelok fitting.
1. Install the switch according to standard installation practices. Be sure
to use thread sealant on all connections.
2. Attach the 702 housing to the switch using the threaded conduit entry.
3. Attach the switch wiring to the terminals as indicated on the wiring
diagram.
4. Connect the battery pack if commissioning the device.
NOTE
Use caution when handling the battery pack. The battery pack may be
damaged if dropped from heights in excess of 20 feet.
815 °C (1500 °F) Process Temperature
540 °C (1000 °F) Process Temperature
250 °C (482 °F) Process Temperature
3 4 5 6 7
4.2 Extension Length (in.)
Reference Manual
00809-0100-4702, Rev AA
September 2007
8 9