Operating manual EMGZ308
5
4 System description
fig. 1: Basic structure of the EMGZ308 Tension Measuring Amplifier (picture shows
single channel version)
E308001e
4.1 Functional description
The force sensors measure the tension force in the processed material and transmit the
measuring value as a mV signal to the hybrid module in the measuring amplifier
EMGZ308. The measuring amplifier amplifies the mV signal depending on configuration.
The resulting feedback value can be transmitted to an analog instrument, a PLC or
equivalent devices. In addition, the force value is shown in the integrated digital display.
4.2 Force sensors
The force sensors are based on the flexion beam principle. The flexion is measured by
strain gauges and transmitted to the measuring amplifier as mV signal. Due to the
wheatstone wiring of the strain gauges, the measured value is according also to the power
supply. So, the force sensors are supplied from the EMGZ308 by a very accurate power
supply.
4.3 Measuring amplifier EMGZ308
The EMGZ308 is a single or double channel analog Tension Measuring Amplifier based
on a hybrid circuit per channel. It is delivered in a robust aluminium housing. All
connections are led through glands to screw terminals. There can be connected 1 or 2
force sensors of 350
Ω
to each channel. The hybrid modules provide the highly accurate
5V power supply and amplify the mV signals of the force sensors to a level of 10V and
20mA. Tension and current output are active the same time. The hybrid technology
ensures both good thermal and electrical characteristics. Measuring circuit and power
supply are galvanic insulated.
Setting of gain and offset is done by 2 trimmers. For filtering of the signals, non-
polarized capacitors can be soldered.
Infinite adjustment of gain and offset
Setting by trimmers is used to get a standardized output signal (i.e. 10V) from any kind of
sensor signal. This ensures accurate amplifying of the signal and maximum immunity to
any interference of the signal cable.
