Brochure/Catalogue

Different types of analogue signalling
The working environment can be measured in many different
forms, e.g. in terms of temperature, humidity or air pressure.
The values of these physical variables change constantly.
Components that monitor the status and changes of a given
environment and provide alerts of any changes must be able
to continuously display the changes taking place.
In industrial and process automation, the outputs received
from eld sensors, switches and transmitters provides
measurement and status data which becomes the analogue
and digital inputs (AI and DI) for the control system. Similarly,
control signals are passed from the control system to eld
control equipment such as analog and digital valves and
actuators.
If automation processes are expected to reach certain
statuses or keep them constant, then analogue signal
conditioning is required. It is also important in areas where
this has already been part of long established practice, e. g.
in process engineering or the chemicals industry.
In process engineering, standardised electrical signals are
normally used. Currents of 0 … 20 mA, 4 … 20 mA or
voltages of 0 ... 10 V have become established as the output
variables for sensors recording various different physical
parameters.
Weidmüller takes account of the growing preference for
automation – including and the resulting need for analogue
signal conditioning – and offers a wide range of products
tailor-made to the requirements involved in handling sensor
signals. Units for the common signals (0 ... 20 mA,
4 ... 20 mA, 0 ... 10 V) generate an output signal as a
proportional value of the variable input signal. “Protective
separation”, e.g. of the sensor circuit from the evaluation
circuit, is also taken into account. “Protective separation”
prevents mutual interference among several sensor circuits,
e.g. as in the case of earth loops in interlinked measuring
circuits.
The wide range of Weidmüller products completely covers
the functions involved in signal conversion, signal separation
and signal monitoring. The products can thus handle nearly
all applications in industrial measuring technology, and
safeguard elementary functions between eld signals and
further processing systems. The mechanical properties of
the products are built up around a consistent concept.
Signal converters can be used with other Weidmüller
products and combined with each other. They are designed
to entail a minimum wiring workload and maintenance in
both electrical and mechanical terms.
The product range contains the following functions:
• DC/DC converters
• Current converters
• Voltage converters
• Temperature converters for resistance thermometers
(RTDs) and thermocouples
• Frequency converters
• Potentiometer transducers
• AC transducers
• Bridge transducers (strain gauges)
• Threshold monitoring modules
• AD/DA converters
The products are available as pure signal converters, or with
2-port or 3-port isolation and a choice of passive or output
loop powered or auxiliary powered, depending on the
application requirements.
Introduction
W
Technical appendix/Glossary
W.4 2729490000