WirelessHART Rosemount 2160 WirelessHART, Reference Manual

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Reference Manual
00809-0100-4160, Rev AB
March 2010
Rosemount 2160
1-4
Measurement Principle
The Rosemount 2160 is designed using the principle of a tuning fork.
A piezo-electric crystal oscillates the forks at their natural frequency. Changes
to this frequency are continuously monitored.
The frequency of the vibrating fork sensor changes depending on the medium
in which it is immersed. The denser the liquid, the lower the frequency.
When used as a low level alarm , the liquid in the tank or pipe drains down
past the fork, causing a change of natural frequency that is detected by the
electronics and
switches the output state to a Dry condition .
When the 2160 switch is used as a high level alarm , the liquid rises in the
tank or pipe making contact with the fork, causing the output state to switch to
a Wet condition .
The output state, along with other parameters, are regularly transmitted over
a secure wireless connection to a Smart Wireless Gateway.
Short Fork Technology
The natural frequency (~1300Hz) of the fork avoids interference from plant
vibration that may cause false switching. This allows for minimum intrusion
into the tank or pipe through the use of a short fork.
Using Short Fork Technology, the Rosemount 2160 can be used in almost all
liquid applications. Extensive research has maximized the operational
effectiveness of the fork design, making it suitable for most liquids including
coating liquids, aerated liquids, and slurries.
Special Features
Instrument Health Monitor and Continuous Self-Check
The 2160 continuously performs instrument health diagnostics to self-check
the condition of the fork and sensor. These diagnostics can detect damage to
the forks including corrosion, internal or external damage to the forks, and
breakages to the internal wiring.
See “Operation Mode” on page 2-8 for further information.
Fork Design
The “fast drip” fork design draws liquid away from the fork tips, and together
with a short switching delay, allows the 2160 to react quickly and with greater
sensitivity to density variations.
Battery Powered
The 2160 is powered by an integral battery. The fork sensor requires very little
power and the battery life remains long even with fast update rates.
See “Battery Installation” on page 3-6 for further information.
Adjustable Time Delay
There is also a user-selectable time delay to virtually eliminate the risk of false
switching in turbulent or splashing applications.
See “Sensor Output Delay” on page 2-9 for further information.