Set The Switches - Emerson Rosemount 148 Reference Manual

Reference Manual
00809-0100-4148
Example
Figure 2-3: Typical North and South American Installation
A. Threaded thermowell
B. Standard extension
C. Threaded style sensor
D. Universal head
E. Conduit entry
2.4

Set the switches

2.4.1 Failure mode
As part of normal operation, each transmitter continuously monitors its own performance.
This automatic diagnostics routine is a timed series of checks repeated continuously. If
diagnostics detect an input sensor failure or a failure in the transmitter electronics, the
transmitter drives its output to low or high alarm depending on the failure mode
configuration. If the sensor (process) temperature value is out of range, the transmitter
outputs default saturation values. Low end saturation levels are either 3.90 or 3.80 mA and
the high end saturation level is 20.5 mA. Corresponding NAMUR compliant operation
levels are 3.80 and 20.5 mA. These values are also custom configurable by the factory or
using the Rosemount 148 PC Programmer interface. See
how to change the alarm and saturation levels with the 148 PC Programmer.
Note
Microprocessor failures cause high alarm regardless of alarm direction (high or low)
choice.
The values to which the transmitter drives its output in failure mode depend on whether it
is configured to standard, NAMUR-compliant, or custom operations. See (★) for standard
and NAMUR-compliant operation parameters in the Rosemount 148
WARNING
Explosions
Fully engage enclosure covers to meet explosion-proof requirements.
A
B
D
C
E
Configuration
Installation
June 2019
for instructions on
Product Data Sheet.
15