ABB KM26 Operating Instruction page 13

KM26 | M AG N ET I C LE V EL G AUG E | O I/KM 2 6 -EN RE V I
. . . 3 Mounting
Limit switches
To signal specific liquid levels, the KM26 can be equipped with
several different types of ABB limit switches. Magnetically
actuated limit switches are the most commonly used devices.
They can be clamped to the measuring chamber and are
adjustable over the entire measuring range. They are actuated
by a magnet incorporated into the float. The process
operating conditions will define what limit switch type may
be used (table 2).
Available magnetically actuated switches
Reed type
Cam action type
Pneumatic type
Table 2 - Available magnetically actuated switches
ABB also provides limit switches such as vibrating forks and
thermal dispersion switches that provide a trip point and are
activated by sensing actual level and are 'independent' of
float travel (magnet position).
Alternate limit switch technologies:
• Liquid vibrating forks: RS85
• Thermal dispersion switches: TX
ABB switches can be delivered as factory assembled to the
KM26 in most cases (figure 13). Please consult the applicable
limit switch product data sheets for specifications,
dimensions, ratings, and approvals.
1
1
1. MLG switches - LMS100, MS40 or MS41
2. RS85 or TX switches
Figure 13 - KM26 with level switches
Limit switch use
The MLG switch will provide either a normally open or
normally closed dry contact which may be used to activate
external devices such as alarms or solenoids. Its main
application is to sense the passing of a magnetic float in a
KM26, or similar chamber, attached to a vessel containing a
fluid. These trip points can be used for alarms or to activate a
pump motor starter relay.
The MLG switch is mounted using two stainless steel clamps
that pass around the mounting ears attached to the switch
housing. The switch can be easily positioned by loosening
LMS100
the clamp and sliding the switch to the correct position on
MS40, MS40EX, and MS41
the chamber. Other switches can be added at any time,
PS45
without the concern for additional process piping or valves.
Note that two switches can be mounted so that they can trip
at the same point. The switch can be easily positioned by
loosening the clamp with a 5/16 in. nut driver and sliding the
switch to the correct position on the chamber (figure 14).
Figure 14 - LMS100 mounted using SS clamps
2
2
13