Emerson Rosemount 3051 Reference Manual page 34

Configuration
August 2019
button. This creates a linear relationship for expected terminal voltage values along the
operating region from 4-20 mA. See
Figure 2-16: Baseline Operating Region
A. Terminal voltage
B. 4 mA
C. Output current
D. 20 mA
Overview
Emerson ships transmitters ordered with power advisory diagnostic (option code DA0)
with power advisory off as default and without any loop characterization performed. Once
you have installed and powered up the transmitter, you must perform loop
characterization for Power Advisory diagnostic to function.
When you initiate a loop characterization, the transmitter checks to see if the loop has
sufficient power for proper operation. Then the transmitter drives the analog output to
both 4 and 20 mA to establish a baseline and determine the maximum allowable terminal
voltage deviation. Once this is complete, you enter a sensitivity threshold called Terminal
Voltage Deviation Limit, and a check is in place to make sure this threshold value is valid.
Once you have characterized the loop and set the terminal voltage deviation limit, power
advisory actively monitors the electrical loop for deviations from the baseline. If the
terminal voltage has changed relative to the expected baseline value, exceeding the
configured terminal voltage deviation limit, the transmitter can generate an alert or alarm.
Note
Power advisory diagnostic in the Rosemount
and detects changes in the terminal voltage from expected values to detect common
failures. It is not possible to predict and detect all types of electrical failures on the 4-20
mA output. Therefore, Rosemount cannot absolutely warrant or guarantee that the power
advisory diagnostic will accurately detect failures under all circumstances.
Terminal voltage
This field shows the current terminal voltage value in volts. the terminal voltage is a
dynamic value and is directly related to the mA output value.
34
Figure 2-16.
™ ®
3051 HART Pressure Transmitter monitors
Reference Manual
00809-0100-4007
Rosemount 3051