Emerson Rosemount 644 Reference Manual page 32

Section 2: Configuration
April 2015
Average temperature configuration with LOI
To configure average temperature on the LOI, the Units and Damping values must be set
separately. Reference
Figure 2-9. Configuring Average Units with LOI
* Available only if option code (S) or (D) is ordered.
** Available only if option codes (S) and (DC) are both ordered, or if option codes (D) and (DC) are both ordered.
Figure 2-10. Configuring Average Damping with LOI
* Available only if option code (S) or (D) is ordered.
** Available only if option codes (S) and (DC) are both ordered, or if option codes (D) and (DC) are both ordered.
Note
If Sensor 1 and/or Sensor 2 should fail while PV is configured for average temperature and Hot
Backup is not enabled, the transmitter will go into alarm. For this reason, it is recommended
when PV is Sensor Average, that Hot Backup be enabled when dual-element sensors are used, or
when two temperature measurements are taken from the same point in the process. If a sensor
failure occurs when Hot Backup is enabled, while PV is Sensor Average, three scenarios could
result:



In the first two scenarios, the 4-20 mA signal is not disrupted and the status available to the
control system (via HART) specifies which sensor has failed.
22
Figure 2-9
VIEW CONFIG
SENSOR CONFIG
UNITS UNITS
RERANGE
LOOP TEST
DISPLAY
EXTENDED MENU
EXIT MENU
VIEW CONFIG
SENSOR CONFIG
UNITS UNITS
RERANGE
LOOP TEST
DISPLAY
EXTENDED MENU
EXIT MENU
If Sensor 1 fails, the average will only be reading from Sensor 2, the working sensor
If Sensor 2 fails, the average will only be reading from Sensor 1, the working sensor
If both sensors fail simultaneously, the transmitter will go into alarm and the status
available (via HART) states that both Sensor 1 and Sensor 2 have failed
and Figure 2-10 below for where to find these in the menu.
CHANGE ALL
SENSOR 1 UNITS
SENSOR 2 UNITS*
DIFFRNTL UNITS*
AVERAGE UNITS* AVERAGE UNITS
1ST GOOD UNITS**
BACK TO MENU
EXIT MENU
CALIBRAT
DAMPING DAMPING
VARIABLE MAP
TAG
ALARM SAT VALUES
PASSWORD
....
Reference Manual
00809-0200-4728, Rev RA
DEG C UNITS
DEG F UNITS
DEG R UNITS
KELVIN UNITS
MV UNITS
OHM UNITS
BACK TO MENU
EXIT MENU
PV DAMP
SENSOR 1 DAMP
SENSOR 2 DAMP*
DIFFRNTL DAMP*
AVERAGE DAMP AVERAGE DAMP*
1ST GOOD DAMP**
BACK TO MENU
EXIT MENU
Configuration