Emerson Rosemount 644 Reference Manual page 59

Reference Manual
00809-0200-4728
3.3.4 Mechanical
Location
When choosing an installation location and position, take into account the need for access
to the transmitter.
Special mounting
Special mounting hardware is available for mounting a Rosemount 644 Head Mount
Transmitter to a DIN rail or assembling a new Rosemount 644 Head Mount to an existing
threaded sensor connection head (former option code L1).
3.3.5 Electrical
Proper electrical installation is necessary to prevent errors due to sensor lead resistance
and electrical noise. For best results, shielded cable should be used in electrically noisy
environments.
Make wiring connections through the cable entry in the side of the housing. Provide
adequate clearance for cover removal.
3.3.6 Environmental
The transmitter electronics module is permanently sealed within a plastic enclosure,
resisting moisture and corrosive damage. Verify that the operating atmosphere of the
transmitter is consistent with the appropriate hazardous locations certifications.
Temperature effects
The transmitter will operate within specifications for ambient temperatures between –40
and 185 °F (–40 °C and 85 °C). Heat from the process is transferred from the thermowell to
the transmitter housing. If the expected process 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 the process.
Figure 3-1
temperature rise and extension length.
Emerson.com/Rosemount
provides an example of the relationship between transmitter housing
Hardware Installation
March 2021
59