Limit Switch; Measuring Range - HBM MC2A Bedienungsanleitung

MC2A

4.3 Limit Switch

The amplified signal is compared here with a preset limiting value (reference
voltage). Potentiometer P 23 is used to set the desired reference voltage to a
value within the 0 ... + 5 V limits.
When the set limit value is exceeded a transistor connects through and no
voltage is applied to the open collector output (terminal 23/7) (terminal 23/7
connected to terminal 23/8 via T21). The switching point can be set as fol-
lows: Connect a voltmeter to measurement point 10 (see circuit diagram) and
use P23 to set the desired reference voltage.
In order to avoid "fluttering" around the switching point, the tripping point is lo-
wer than the set switching point by the hysteresis voltage of 25 mV.
The hysteresis voltage can be increased by soldering a smaller resistance
R58 value, in. The value is to be determined empirically.
Works setting 25 mV = 10 M; resistance value is inversely proportional to
the hysteresis voltage.

4.4 Measuring range

80 mV/V; 8 mV/V
The measuring amplifier MC2A is equipped with two selectable ranges. The
switch S 21 located on the printed circuit board serves to set either of the two
ranges: position 1, circle visible, (MR 1 = " 80 mV/V) or position 2, circle
obscured (MR 2 = " 8 mV/V).
In addition the screw driver potentiometer P 22 may be used for range fine ad-
justment giving up to " 20% of the set range value.
MB 2 can be set in the 8 ... 80 mV/V range by replacing resistor R 39 with
another value, which can be calculated by the following equation:
Rx + 80 @ 12.4
M
M = desired measuring range in mV/V
A1974−2.4 en/de/fr
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HBM