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Reference Manual
00809-0100-4021, Rev DA
November 2004
Rosemount 3144P
3-26
HART
NOTE
Take careful note of the process variable output order. You must configure the
HART Tri-Loop to read the variables in the same order.
5. Select OK to return the control loop to automatic control.
AMS
Right click and select “Configuration” from the menu screen. Select “Set
Variable Mapping”. The “Set Variable Mapping wizard” will go through the
mapping procedure.
Special Considerations
To initiate operation between a 3144P transmitter with dual-sensor option and
the HART Tri-Loop, consider the configuration of both the differential,
average, first good temperatures, Sensor Drift Alarm, and Hot Backup
features (if applicable).
Differential Temperature Measurement
To enable the differential temperature measurement feature of a
dual-sensor 3144P operating in conjunction with the HART Tri-Loop,
adjust the range end points of the corresponding channel on the HART
Tri-Loop to include zero. For example, if the secondary variable of the
transmitter is to report the differential temperature, configure the
transmitter accordingly (see “Set Process Variable Output Order” on
page 3-25) and adjust the corresponding channel of the HART Tri-Loop so
one range end point is negative and the other is positive.
Hot Backup
To enable the Hot Backup feature of a 3144P transmitter with dual-sensor
option operating in conjunction with the HART Tri-Loop, ensure that the
output units of the sensors are the same as the units of the HART
Tri-Loop. Use any combination of RTDs or thermocouples as long as the
units of both match the units of the HART Tri-Loop.
Using the Tri-Loop to Detect Sensor Drift Alarm
The dual-sensor 3144P transmitter sets a failure flag (via HART) whenever a
sensor failure occurs. If an analog warning is required, the HART Tri-Loop can
be configured to produce an analog signal that can be interpreted by the
control system as a sensor failure.
Use these steps to set up the HART Tri-Loop to transmit sensor failure alerts.
1. Configure the dual-sensor 3144P variable map as shown.
2. Configure Channel 1 of the HART Tri-Loop as TV (differential
temperature). If either sensor should fail, the differential temperature
output will be +9999 or –9999 (high or low saturation), depending on the
position of the Failure Mode Switch (see “Failure Mode and Security
Switch Locations” on page 2-5).
Variable Mapping
PV Sensor 1 or Sensor Average
SV Sensor 2
TV Differential Temperature
QV As Desired