Emerson Rosemount 3101, Reference Manual

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51
Reference Manual
00809-0100-4840, Rev CB
Section 4: Starting up
February 2015
Starting up
4.4.14 Selecting the Lost Echo action (on the 3102/3105)
Screen display: AL
Default: Hold
Faults are indicated by a fixed high or low output current, outside the 4–20 mA normal range,
and which is selected by the model code that was chosen when ordering the transmitter
(see the Special Alarms Options codes in the section
“Ordering information” on page 87 ).
The exception is that a separate output current action can be user-selected for a lost echo
condition, where a target echo is lost for 900 seconds or more.
There are three Lost Echo output current actions to choose from:
Hi The current on the two-wire loop increases to 21.75 mA (for the
Rosemount Standard) or 22.5 mA (for NAMUR NE43), depending on the
full model code (see
“Ordering information” on page 87 ).
The current is fixed at that level until the correct target echo is
recovered. The display flashes alternately “LE” and the maximum
reading (equal to the Bottom Reference setting).
Hold The current freezes at the last PV value and stays frozen until the correct
target echo is recovered. The display flashes alternately “LE” and the last
known PV.
Lo The current on the two-wire loop decreases to 3.75 mA (for Rosemount
Standard) or 3.6 mA (for NAMUR NE43), depending on the full model
code (see
“Ordering information” on page 87 ).
The current is fixed at that level until the correct target echo is
recovered. The display flashes alternately “LE” and the minimum reading
(“0000”).
Note
Table 5-1 on page 59 has a list of faults and alarms.
Faults (e.g. device malfunction) indicated on the output current have priority over the selected
lost echo output current action.
Alarms e.g. outside temperature limits, and most faults, are indicated on the display. The 3102
can also indicate faults using its relay outputs.
The 900 seconds is factory set and is changeable in the field
(see
“Setting lost echo time (on the 3102/3105)” on page 64 ).
The AL menu option is in the programming menu. See Figure C-2 on page 103 for a map of the
menu structure and how to access the menu options.