HBM MC3 Bedienungsanleitung Seite 10

10
Strain gage
full bridge
(300 Ω ... 1400 Ω)
Fig. 2.1: Block circuit diagram: DV = Differential amplifier; TV = Carrier fre-
quency amplifier; D = Demodulator; EV/TP = Output amplifier with low
pass; G = Generator; GR = Limit value switch; K = Stabilizer; S 21 =
Measuring range selector switch; P 21, P 22 = Zero signal adjustment
The switching point of the limit switch GR can be set in the range of 0V...+ 5V.
Both the set voltage and the measurement signal are applied to a comparator.
If the set level should be exceeded by the measurement signal, a transistor is
switched. Switching processes can be carried out via the collector connec-
tions which are taken out. Maximum load 30 V; 50 mA; switching capacity
1.5 W.
If the MC3 should be equipped with an optional final stage, operation can be
carried out with "live zero". An impressed current of from 4 mA (zero signal,
transducer unloaded) to 20 mA (rated output signal) is then available at the
output. This is particularly advantageous because faults such as line breaks
or other electrical defects are recognised immediately. Current or voltage out-
put can be selected by a slide switch.
HBM
MC3
A1705−3.2 en/de/fr