6
Reference Manual
00809-0200-4702, Rev CA
Section 1: Introduction
February 2013
Introduction
1.4.4 Electrical
Caring for the Power Module
The Rosemount 702 Wireless Discrete Transmitter is self-powered. The included Black Power
Module contains two “C” size primary lithium/thionyl chloride batteries. Each battery contains
approximately 2.5 grams of lithium, for a total of 5 grams in each pack. Under normal
conditions, the battery materials are self-contained and are not reactive as long as the batteries
and the power module are maintained. Care should be taken to prevent thermal, electrical, or
mechanical damage. Contacts should be protected to prevent premature discharge.
Use caution when handling the power module, it may be damaged if dropped from heights in
excess of 20 feet (6.10 m).
Making Switch Connections
Make switch connections through the cable entry in the side of the connection head. Be sure to
provide adequate clearance for cover removal.
1.4.5 Verifying Operating Atmosphere
Verify that the operating atmosphere of the transmitter is consistent with the appropriate
hazardous locations certifications.
Isolating the transmitter from sources of heat
The transmitter will operate within specifications for ambient temperatures between -40 and
185 °F (-40 and 85 °C). Heat from the process is transferred from the switch to the transmitter
housing. If the expected process temperature is near or beyond specification limits, consider
using an extension, or remote mount the transmitter to thermally isolate it from the process.
Figure 1-4 provides an example of the relationship between the transmitter housing
temperature rise and the extension length.
Figure 1-4. Rosemount 702 Transmitter Connection Head Temperature Rise vs. Extension
Length
Housing Temperature Rise, Above
Ambient °C (°F)
3 4 5 6 7 8 9
0
60 (108)
50 (90)
40 (72)
30 (54)
20 (36)
10 (18)
4.2
55
Extension Length (in.)
815 °C (1500 °F) Process Temperature
540 °C (1000 °F) Process Temperature
250 °C (482 °F) Process Temperature
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