Conductive electrode relay SRE-200-U0

Applications

The fill level limit switch SRE-200 is low-priced equipment for limit value detection or two-point-control in containers with electrically conductive filling material.
With this equipment small pumps, contactors and signaling devices can be directly controlled.

The fill level limit switch SRE-200 is two-cannel equipment, whose electrode channels are galvanically seperated.
At the contats mass-min-max the respective electrodes are connected, which represents the electrodes in the container that should be supervised.
In metal containers the ground connection is connected to the container wall. At the electrodes an alternating voltage of approx. 8 V is generated, thus affecting of the probes is completely harmless.
As soon as the electrically conductive filling material touches the probes, a small alternating current flows. Because of the minimum current (1.5 mA) a electrolytic decomposition of the filling material is avoided.
At a two-point-control the relay is switched, if the min and the max electrode are connected together by the filling material and shifts back only again if the connection of the filling material between the two electrodes breakes.
A 1-point control operates only with the mass and the max electrode. The relay switches, if the filling material connects the mass and the max electrode and switches back, if the electrodes does not have a connection by the filling material any more. A vibration of the relay, caused e.g. by wave fluctuations of a liquid is impossible, since the electrode relay switches in principle with a time delay of approx. 1,5 seconds.
At the front side the sensitivity of the probes can be exactly adjusted by a 10-turn potentiometers by a screwdriver. Additionally the relay function can be inverted by a switch at the pcb.