Data Sheet

Level Instruments
D103219X012
Product Bulletin
11.2:Level
February 2015
6
Fisher L2, L2e, and L2sj
Liquid Level Controllers
Rugged L2, L2e, and L2sj liquid level controllers use a
displacer type sensor to detect liquid level or the
interface of two liquids of different specific gravities.
The reliability of the design make these controllers well
suited for high pressure liquid level applications in
natural gas production, compression, and processing
industries.
The L2 and L2sj devices deliver a pneumatic output
signal to a control valve.
The L2e device uses a single pole double throw (SPDT)
dry contact electric switch to provide differential gap
(DG) control or liquid monitoring. It can be used to
provide an electric control signal to an electrically
actuated control valve.
The sensor uses a threaded 2 NPT connection to the
vessel. Standard constructions use materials that
comply with the requirements of NACE MR0175‐2002.
L2, L2e, and L2sj controllers, in combination with the
sensor, work on the principle that a body immersed in
liquid will be buoyed up by a force equal to the weight
of the liquid displaced. The buoyant force and
resultant movement of the displacer in the liquid is
transmitted to the controller which delivers the signal
to a control valve.
L2 Liquid Level Controllers
Snap‐Acting or Throttling Control... One standard
controller available as either throttling or snap‐acting.
Field‐Reversible Output... The controller can be
adjusted in the field for direct or reverse action without
additional parts. The controller also has adjustable
gain sensitivity.
Easy Maintenance... Both the controller and the sensor
can be easily disassembled to inspect the process seals
and for maintenance.
Figure 6. Fisher L2 Liquid Level Controller
W8418‐1
L2e Electric Level Controllers
Effective Level Loop Tuning… Intuitive Zero and Span
adjustments allow flexibility in setting loop
performance over a level range of 5.0 to 559 mm
(0.2 to 22 inches).
More Reliable Control… Premium quality
hermetically-sealed switch with gold contacts and
advanced knife-edge sensing provide highly
dependable and accurate liquid level control.
Environmentally Responsible… Replacing a
conventional pneumatic level loop with fully electric
level control eliminates controller and dump valve
venting and requires less maintenance.
Figure 7. Fisher L2e Liquid Level Controller
X0660