Emerson Rosemount 248 Reference Manual page 11

Reference Manual
00809-0100-4825
2.4.4 Electrical
Proper electrical installation is necessary to prevent errors from sensor lead resistance and
electrical noise. For best results, shielded cable should be used in electrically noisy
environments. A resistance between 250 and 1100 ohms must be present in the loop for
communication with a Field Communicator.
Make wiring connections through the cable entry in the side of the connection head being
sure to provide adequate clearance for cover removal.
2.4.5 Environmental
The transmitter electronics module is permanently sealed within the housing, to resist
moisture and corrosive damage. Verify that the operating atmosphere of the transmitter
is consistent with the appropriate hazardous locations certifications.
Temperature effects
The transmitter operates within specifications for ambient temperatures between –40 and
185 °F (–40 and 85 °C)
to the transmitter housing so if the expected process temperature is near or above
specification limits, consider using an additional thermowell lagging, and extension
nipple, or a remote mounting configuration to isolate the transmitter from the process
Note
Extended ranges available with BR5 and BR6 option codes for extending the lower ambient
temperature limit to –50 and –60 °C, respectively.
Figure 2-1
temperature rise and extension length.
Figure 2-1: Rosemount 248 Transmitter Connection Head Temperature rise vs.
Extension Length
(1) Extended ranges available with BR5 and BR6 option codes.
Rosemount 248 Temperature Transmitter Reference Manual
(1)
. Process heat from the process is transferred from the thermowell
provides an example of the relationship between transmitter housing
Installation
May 2019
11