2 Setting up a system
MX Modules A04089_07_E00_02 HBM: public 33
transducer (metal housing) and the amplifier (housing is connected to the earth
conductor).
If there are differences in potential in the measuring system, a potential
compensating line must be laid (reference value: Highly flexible stranded wire, wire
cross section 10 mm
2
). Signal and data leads must be set up physically separated
from current‐carrying power lines. Ideally, cable ducts made of sheet metal with an
internal partition should be used. Signal ground, earth and shielding must be laid out
as separated as possible.
In order to minimize the influence of electromagnetic interferences and differences in
potential, the signal ground and earth (or shielding) are designed to be physically
separate in the HBM devices. The mains earth connector or a separate earth
potential lead should serve as the earth connection as is the case for example
regarding potential compensation in buildings. The earth cable should not be
connected to a radiator body, water pipe or similar objects.
Active transducer connection
Some modules can supply active transducers with a supply voltage of 5-24 volts.
When using the adjustable transducer excitation, electrical isolation from the supply
voltage of the amplifier is not required.
The maximum permissible power consumption is 700 mW per channel and 2 W total.
If the power consumption is more than 700 mW on one channel, the transducer
excitation of this channel switches off. If the power consumption exceeds a total of 2
W, the device may switch off.
CAUTION
Check the correct voltage setting when connecting a sensor. Too high a voltage
can destroy the sensor. The voltage value is a part of the MX module
parameterization and can only be changed with a new parameterization. The
sensor supply is switched off in the delivery condition.
2.7.1 TEDS
TEDS (Transducer Electronic Data Sheet) refers to the electronic data sheet of a
transducer or sensor that is stored in a small electronic chip or appropriate module
which is permanently connected to the device in the transducer housing, the
inseparable cable or the connector plug.
TEDS allows automatic parameterization of a channel immediately after a sensor
has been connected. Every measurement channel allows reading or writing of
sensor data to the TEDS chip. The sensor database is used to describe a sensor. If
a TEDS sensor is connected, this information is written. In addition, valuable meta‐
data such as calibration data are delivered providing important information for the
traceability of measurements or tests.
NOTE
The function and working method of TEDS are defined in Standard IEEE1451.4.
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