Emerson Rosemount 2120, Справочное руководство

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Figure 2-2: “Fast drip” forks
2.5.3 Heartbeat LED
Each electronics cassette of the level switch has a ‘heartbeat’ LED indicating its operation
status, which can always be seen from all angles through a lens in the cover of non-metal
housings. The LED flashes when the level switch output is ‘off’ and is constantly lit when
'on'.
The LED gives a constant indication that the level switch is functioning correctly (different
flash rates are used to indicate a product malfunction) and gives a local indication of the
process state.
2.5.4 Mode switch and adjustable output delay
A mode switch on the electronics cassette allows the level switch output to be 'on' or 'off'
when the forks are wet or dry. Typically is set to 'dry on' (for a low-level point alarm) or 'wet
on' (for a high-level point alarm). There is also a user-selectable time delay (0.3, 1, 3, 10, or
30 seconds) on the electronics cassette to virtually eliminate the risk of false switching in
turbulent or splashing applications.
2.5.5 Magnetic test point
A magnetic test point is located on the side of the housing, allowing a functional test of
the Rosemount 2120 and a system connected to it. Holding a magnet to the test point
causes the output to change state.
2.5.6 Electrical connections
The terminal blocks extend above the housing and give easy terminal access. Electrical
protections make electrical hook-up safe and easy.
Reference Manual Level switch overview
00809-0100-4030 March 2022
Rosemount 2120 Level Switch 13