In tanks with conductive liquids, reliable switching starts with clear detection of the actual level, not every small wave movement. SRA-100-U0 evaluates conductive probes for limit level detection or control in media such as water, alkalis and acids, using a low functional voltage of approx. 9 V at the electrodes.
The relay supports different level tasks with one compact 22.5 mm DIN-rail housing. It can operate with relay self-holding and min./max. switching points, or as a dual limit level detector with two separate outputs. This makes it suitable for overflow protection, dry-run protection, two-point control and moisture detection.
Commissioning is easier because the response sensitivity can be adapted to the conductivity of the liquid via coarse and fine adjustment. Alternating voltage helps avoid corrosion on the probe rods and electrolytic decomposition of the medium, while an adjustable switching delay of up to approx. 8 s suppresses tank wave movement. A wide-range 20...253 V AC/DC supply supports flexible installation.
The unit works with one or two level electrodes and a common reference electrode. In metallic tanks, the tank wall can be used as the reference; in non-metallic tanks, a separate electrode is used.
A small alternating current flows when the conductive medium connects the reference and a level electrode. The evaluation electronics convert this signal into a relay output.
The device can work with relay self-holding and min./max. switching point, or as a dual limit level detector with two separate outputs.
Line monitoring is available when used with level or measuring probes that include an integrated LBM module.
The relay contacts switch up to 250 V AC, 10 A AC and 2500 VA.
The electronics are built into a 22.5 mm wide modular DIN-rail housing for control cabinet installation.
