3UG4622-1AW30 Datasheet, PDF (82/114 Pages) List of Unclassifed Manufacturers – Monitoring and Control Devices

Monitoring Relays
3UG Monitoring Relays for Electrical and Additional Measurements
Level monitoring
■ Overview
The 3UG35 01 level monitoring relay is used together with the
2- or 3-pole sensors to monitor the levels of conductive liquids.
■ Function
The principle of operation is based on measuring the electrical
resistance of the liquid between two immersion sensors and a
reference terminal. If the measured value is lower than the
sensitivity set at the front, the output relay changes its switching
state. In order to exclude electrolytic phenomena in the liquid,
the sensors are supplied with alternating current.
Two-level control: the output relay changes its switching state as
soon as the liquid level reaches the maximum sensor, while the
minimum sensor is submerged. The relay returns to its original
switching state as soon as the minimum sensor no longer has
contact with the liquid.
For safe resetting, the supply voltage must be interrupted for
at least 0.5 s (T3).
The delay times T1 and T2 of the output relay have not been
included in the diagram in order to enhance clarity.
Note:
It is also possible to connect other resistance sensors to the Min
and Max terminals in the range 5 to 100 kW, e.g. photoresistors,
temperature sensors, encoders based on resistance etc.
The monitoring relay can therefore also be used for other
applications apart from monitoring the levels of liquids.
A 1 /A 2
1
2
N S B 0_00961
T3
3
4
5
1 M a x im u m le v e l ¹)
2 M in im u m le v e l 1)
3 M o n ito r e d le v e l
4 O u tp u t r e la y
F u n c tio n O V E R
5 O u tp u t r e la y
F u n c tio n U N D E R
1 _{) D e te r m in e d b y th e a r r a n g e m e n t}
o f th e p r o b e s in th e m o n ito r e d liq u id .
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Siemens LV 1 T · 2006