Functional Description - Tecsis EGS08 Betriebsanleitung

Betriebsanleitung/Operating manual
EGS08

1 Functional description

The units operate as triple comparators for sensors with current output.
The sensor input can be configured for the 1-9mA or 4-20mA signal range.
An adjustable potentiometer per comparator enables the setting of a switching
threshold for each one which corresponds to a certain loading of the connected
strain gauge force transducers. Each comparator output controls a relay and an
indicator LED. The switching function of each relay can be set to closed or switch-
off should the threshold value be exceeded. An additional comparator switches all
relays to the overload condition if there is a broken wire from the sensor.
The diagram below shows the principle of operation graphically for each
comparator.
U
MP
Relay in switch off mode
On
Off
Relay in switch on mode
On
Off
According to this an increase in the force leads to an increase in the voltage
measured.
By turning one of the controllers POT1, 2 or 3 the switching threshold for that
comparator is changed. If the force is increasing when the switching threshold is
reached the connected relay of the comparator is switched over. If the force on the
strain gauge force transducer is reduced again, the voltage measured falls. When
the switch back threshold of the comparator is reached the relay is switched back
again. Between the switching off and switching on thresholds there is a hysteresis
difference, which expressed as a voltage has a value of about 20mV or 70mV.
Thus, fluttering of the relay when there are very small force variations is avoided.
14
F
hysteresis
adjusted switching threshold at the Potentiometer
corresponds to the swelling force
shift-in switching threshold (swelling force - hysteresis)
F
F
F
F
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