Emerson Rosemount 3490 Series Reference Manual page 92

Getting started
January 2021
Table 4-6: Current Output Parameters
Parameter
P400
P401
P402
P404
P210
Related information
Control unit reporting of alarms and faults
Data logging on the Rosemount 3493
92
Description
Low Range Val This is the minimum control unit PV value
represented by 4 mA.
Up Range Val This is the maximum control unit PV value
represented by 20 mA.
Alarm Actions Optional for determining how an alarm, if selected in
the ALARM menu, is indicated on the Current
Output. Options for P402 are:
• 3.6 mA – fix current output to 3.6 mA to force a
low current limit alarm.
• 3.75 mA – fix current output to 3.75 mA to force
a low current limit alarm.
• Hold – freeze the current output at the present
value.
• 21 mA – fix current output to 21 mA to force high
current limit alarm.
• 21.75 mA – fix current output to 21.75 mA to
force high current limit alarm.
• 22.5 mA – fix current output to 22.5 mA to force
high current limit alarm.
Note
The 3.75 mA and 21.75 mA options are the
Rosemount standard.
The 3.6 mA and 22.5 mA options are the NAMUR
NE43 standard.
There is another alarm condition when the current
output has reached the linear limit i.e. saturated. For
the Rosemount Standard, this is ≤ 3.9 mA or ≥ 20.8
mA. For the NAMUR NE43 standard, this is ≤ 3.8 mA
or ≥ 20.5 mA.
mA Mode On the Rosemount 3493, this optional parameter is
for assigning the Current Output to follow a rolling
average of the calculated control unit PV (typically
flow). To do this, select the Rolling option.
The time period for the rolling averaging is set using
P590, which is also for setting the logging interval.
MCU PV This is used to apply damping to smooth out big
Damping steps in calculated control unit Primary/Process
values (PV).
Reference Manual
00809-0100-4841
Factory default
0.0
100.0
3.6 mA
Instantaneous
0
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