Emerson Rosemount 644 with HART Protocol User Manual

24
Reference Manual
00809-0200-4728, Rev SA
Configuration
July 2018
Configuration
2.8.3 Configure alarm and saturation levels
In normal operation, the transmitter will drive the output in response to measurements between the
lower to upper saturation points. If the temperature goes outside the sensor limits, or if the output
would be beyond the saturation points, the output will be limited to the associated saturation point.
The Rosemount 644 Transmitter automatically and continuously performs self-diagnostic routines. If the
self-diagnostic routines detect a failure, the transmitter drives the output to configured alarm value
based on the position of the alarm switch. The Alarm and Saturation settings allow the alarm settings (Hi
or Low) and saturation values to be viewed and changed.
Failure mode alarm and saturation levels can be configured using a Field Communicator, AMS Device
Manager, and the LOI. The following limitations exist for custom levels:
 The low alarm value must be less than the Low Saturation level.
 The high alarm value must be higher than the High Saturation level.
 Alarm and Saturation levels must be separated by at least 0.1 mA
The configuration tool will provide an error message if the configuration rule is violated.
See table below for the common alarm and saturation levels.
Note
Transmitters set to HART multi-drop mode send all saturation and alarm information digitally; saturation
and alarm conditions will not affect the analog output.
Table 2-4. Rosemount Alarm and Saturation Values
Units - mA
Min Max Rosemount Namur
High alarm 21 23 21.75 21.0
Low alarm
(1)
1. Requires 0.1 mA gap between low alarm and low saturation values.
3.5 3.75 3.75 3.6
High saturation 20.5 22.9
(2)
2. Rail mount transmitters have a high saturation max of 0.1 mA less than the high alarm setting, with a max value
of 0.1 mA less than the high alarm max.
20.5 20.5
Low saturation
(1)
3.6
(3)
3. Rail mount transmitters have a low saturation min of 0.1 mA greater than the low alarm setting, with a
minimum of 0.1 mA greater than the low alarm min.
3.9 3.9 3.8

Emerson Rosemount 644 with HART Protocol Specifications

General

Brand	Emerson
Model	Rosemount 644 with HART Protocol
Category	Transmitter
Language	English