On power-
up, probes Min, Max are submerged and probe AI. is above the level of the liquid. Relays R1 and R2 are energised and the pump is ON : emptying starts, the LED for relay R1 is lit. When
the Min probe emerges, relay R1 de
-energises and the pump if OFF : emptying stops, the LED for relay R1 goes off. If, in the event of a fault, the level continues to rise a
nd reaches proble AI., relay R2 de-
energises and the alarm is triggered : the LED for relay R2 is lit.
This fault can be stored.
Operating principle
Control of the level of a conductive liquid at specific points (high and low levels) with an alarm for a level which is abnormally high or low.
The principle is based on measurement of the apparent resistance of the liquid between submerged probes. When this value is lower than the present threshold on the unit front face, the output
relay R1 and/or the alarm relay R2 change state.
The avoid electrolytic phenomena, an AC current runs across the probes.
Adjusting sensitivity
Set the sensitivity so that the relay will change state when the probes are in contact with the liquid. Then check that the relay returns to its initial position as soon as the probes emerge.
In certain applications, fine-tuning the sensitivity prevents inappropriate detection, such as the presence of foam or bubbles on the surface or the occurrence of leakage impedance between
probes (extended line capacity, humidity, etc).
Note :
Latching of the alarm relay R2 in de
-energised state if a fault occurs can the programmed via a switch on the underside of the underside of the unit (only when the unit is switched off). To reset
alarm relay R2, cut the power, as long as the levels are reset.
Programming
The FN level controller can be programmed using 3 switches on the lower panel :
Note :
Memory, Alarme and Function must only be selected when the unit is switched off.
Unless otherwise specified, the characteristics given are applicable to all or part of the product range selected