Page 185 - EPR Catalog 2015

Liquid level monitors and controls
Function diagrams

Function diagrams - CM-ENN The CM-ENN monitors levels of conductive liquids and is used for example 2
Circuit with 2 electrodes for liquid level monitoring in pump control systems, for dry-running protection
1SVC 110 000 F 0167 of submersible pumps or overflow monitoring of tanks. It is also suitable for
MAX conductivity monitoring of liquids. The measuring principle is based on the
MIN resistance change sensed by single-pole electrodes (wet or dry).
C Instead of electrodes, other sensors or transducers can also be used if their
output quantities are different resistance values. The measuring, output and
A1-A2 supply circuits are electrically isolated for potential separation and to prevent
15/18 electrical interference.
15/16 Due to the integrated ON- or OFF-delay, it is possible to set up time-dependent
liquid controls using only two electrodes (C, MAX). Different liquid levels in
Circuit with 3 electrodes one tank can be controlled by up to 5 CM-ENN (AC version) without mutual
interference.
MAX
MIN
C

A1-A2 1SVC 110 000 F 0168

15/18
15/16

tA = ON-delay, tR = OFF-delay

Function diagram - CM-ENE MIN

MIN 1SVC 110 000 F 0151 The liquid level relays CM-ENE MIN and CM-ENE MAX are used to monitor
C levels of conductive liquids, for example in pump control systems for dry-
running or overflow monitoring.
A1-A2 The measuring principle is based on the occurring resistance change when
13-14 moisting single-pole electrodes. The single-pole electrodes (see also section
Accessories) are connected to the terminals C and MIN or MAX.
Function diagram CM-ENE MAX If the supply voltage is applied to A1-A2 and the electrodes are wet, the output
relay of the CM-ENE MIN is energized and the output relay of the CM-ENE MAX
is de-energized.
The output relay of the CM-ENE MIN de-energizes if the electrodes are no
longer wet. The output relay of the CM-ENE MAX energizes if the electrodes are
no longer wet.

MIN 1SVC 110 000 F 0152
C

A1-A2
13-14

2CDC 110 004 C0210 | Catalog Electronic Products and Relays 2015 | ABB 2/118