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Reference Manual
00809-0100-4021, Rev FB
August 2011
Rosemount 3144P
2-4
Table 2-1. Transmitter Switch
Locations
Write Protect Switch (HART and F
OUNDATION
Fieldbus)
The transmitter is equipped with a write-protect switch that can be positioned
to prevent accidental or deliberate change of configuration data.
Alarm Switch (HART)
An automatic diagnostic routine monitors the transmitter during normal
operation. If the diagnostic routine detects a sensor failure or an electronics
failure, the transmitter goes into alarm (high or low, depending on the position
of the failure mode switch).
The analog alarm and saturation values used by the transmitter depend on
whether it is configured to standard or NAMUR-compliant operation. These
values are also custom-configurable in both the factory and the field using the
HART Communications. The limits are:
• 21.0
I
23 for high alarm
• 3.5
I
3.75 for low alarm
Table 2-2. Values for standard
and NAMUR operation
Simulate Switch (F
OUNDATION
Fieldbus)
Simulate switch is used to replace the channel value coming from the Sensor
Transducer Block. For testing purposes, it manually simulates the output of
the Analog Input Block to a desired value.
MOUNTING
If possible, the transmitter should be mounted at a high point in the conduit
run so moisture from the conduits will not drain into the housing. The terminal
compartment could fill with water if the transmitter is mounted at a low point in
the conduit run. In some instances, the installation of a poured conduit seal,
such as the one pictured in Figure 2-3, is advisable. Remove the terminal
compartment cover periodically and inspect the transmitter for moisture and
corrosion.
Switch Location
Switches
(1)
LCD
Connector
4.4 in. (112 mm)
4.4 in. (112 mm)
(1)
Alarm and Write Protect (HART),
Simulate and Write Protect (F
OUNDATION
Fieldbus)
Standard Operation (factory default)
NAMUR-Compliant Operation
Fail High
21.75 mA
I
23.0 mA
Fail High
21 mA
I
23.0 mA
High Saturation
I
20.5 mA
High Saturation
I
20.5 mA
Low Saturation
I
3.90 mA
Low Saturation
I
3.8 mA
Fail Low
I
3.75 mA
Fail Low
I
3.6 mA
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