15
APPROVED
April 18
Liquid level detection (LS models only)
Liquid level detection is based on a capacitance change. The detection signal is created using an
oscillator with a nominal frequency at approx. 50 kHz.
From the change in frequency it is possible to detect if the tip is in liquid. However, the sensor is
sensitive to all changes in the environment, including the type of the of tip rack, attachment fixtures
etc. Typical frequency values are between 3 kHz – 55 kHz.
Level detection signal is routed to the connector pin 7 (LS output). Signal is frequency modulated
square wave according to the capacitive change.
Level detection value can be queried also with software using specific command (DN). Typical value
without the tip is 240-300, with an increase with tip attached and in liquid. Values will be application
specific with a typical range of 160 – 400.