Emerson Rosemount, Reference Manual

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96
Reference Manual
00809-0100-4021, Rev GC
Section 3: HART commissioning
April 2014
HART® commissioning
3.10.2 Master reset
Master Reset resets the electronics without actually powering down the unit. It does not return
the transmitter to the original factory configuration.
3.10.3 Intermittent sensor detect
The following steps indicate how to turn the Intermittent Sensor Detect (also knows as Transient
Filter) feature
ON or OFF
. W
hen the transmitter is connected to a Field Communicator, use the
fast key sequence and choose ON (normal setting) or OFF .
3.10.4 Intermittent threshold
The threshold value can be changed from the default value of 0.2%. Turning the Intermittent
Sensor Detect feature
OFF or leaving it ON and increasing the threshold value above the default
does not affect the time needed for the transmitter to output the correct alarm signal after
detecting a true open sensor condition. However, the transmitter may briefly output a false
temperature reading for up to one update in either direction (see
Figure 3-9 on page 98 ) up to
the threshold value (100% of sensor limits if Intermittent Sensor Detect is OFF ). Unless a rapid
response rate is necessary, the suggested setting is ON
with 0.2% threshold
.
Figure 3-8. Open Sensor Response
HART 5 Fast Keys
2, 2, 7, 6
HART 7 Fast Keys
2, 2, 7, 6
HART 5 Fast Keys
2, 2, 7, 5, 2
HART 7 Fast Keys
2, 2, 7, 5, 2
HART 5 Fast Keys
2, 2, 7, 5
HART 7 Fast Keys
2, 2, 7, 5
0
0
5
10
15
20
25
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
Tr
ansmitt
e
r O
u
tput (mA
)
Time (seconds)
When Intermittent Sensor Detect is
OFF, a false temperature output is
possible when an open sensor
condition is detected. A false
temperature output in either direction
up to the threshold value (100 % of
sensor limits if Intermittent Sensor
Detect is OFF) is possible when an open
sensor condition is detected.
Normal open sensor responses
High Alarm