Page 184 - EPR Catalog 2015

Liquid level monitors and controls
Function diagrams

Function diagram - CM-ENS

2 Max. 1SVC 110 000 F 0155
Min.
C

A1-A2

11-14
11-12

The CM-ENS monitors levels of conductive liquids and is used for example for liquid level control in pump systems. It can be used for filling or draining tanks for
example. It is also suitable for monitoring the conductivity of liquids. The measuring principle is based on the resistance change sensed by single-pole electrodes.
After the supply voltage is applied to the terminals A1 and A2, the output relay is de-energized. The probes must be connected to C, MAX, MIN. The output relay
energizes if the liquid exceeds the maximum level (C and MAX wet) and de-energizes if the liquid level is below the minimum level (MAX and MIN dry). Basedau m
on the measuring circuit there will be a response delay of approx. 250 ms at maximum sensitivity. Different levels in one tank can be controlled by up to 5 CM-ENS
without interfering with each other.

Function diagram - CM-ENS UP/DOWN

Max. 1SVC 110 000 F 0164
Min.
C

A1-A2

11-14
"DOWN"

11-12

"UP" 11-14
11-12

The CM-ENS UP/DOWN monitors levels of conductive liquids and other media, and is used e.g. for liquid level control in pump systems.
The measuring principle is based on the resistance change sensed by single-pole electrodes. The output relay functions fill (UP) or drain (DOWN) can be selected
on a front-face selector switch. If the "UP" function is selected, the output relay is energized until the MAX electrode becomes wet. Then it is de-energized and
not re-energized until the MIN electrode becomes dry. If the "DOWN" function is selected, the output relay is energized as soon as the MAX electrode becomes
wet. It remains energized until the liquid level has dropped below the MIN electrode. The electrodes can be connected to more than one CM-ENS unit without
interference.

2/117 ABB | Catalog Electronic Products and Relays 2015 | 2CDC 110 004 C0210