Brochure/Catalogue

Relay modules and solid-state relays – Introduction
Relay modules and solid-state relays – Introduction
Our relay modules, solid-state relays and additional value
added services are hugely benecial for our customers:
space-saving installation, control cabinet optimisation,
reduced wiring effort, optimal markability and cost
reductions. Supplemented by our complete portfolio,
Weidmüller offers everything from a single source.
Over the following pages, we would like to explain the world
of relay modules and solid-state relays and provide technical
explanations of the features in the data sheet.
There are three main applications for relay modules and
solid-state relays, which we will explain briey below:
Potential isolation
Many applications require that the control circuit is electrically
isolated from the load circuit. This primarily protects the control
level from interference from the eld, such as:
• Interference currents e.g. from earth and ground loops
• Interference pulses e.g. from inductive effects of transients
Switching amplication/signal adaptation
The separation of the load and control circuits, in
conjunction with the associated options for conguring both
circuits separately, means that relay modules and solid-state
relays are often used for switching amplication and signal
conditioning purposes.
This allows the different voltage potentials of signals from
the control and load circuits to be aligned.
They are also used to amplify current values that exceed the
load capacity of the control unit, e.g. a PLC output.
Contact multiplication
With applications, it is often necessary to control several
load circuits simultaneously with one control signal.
With electromechanical relays, this can be achieved with
multi-channel variants, whereby up to four load circuits can
be switched simultaneously with one control signal, e.g.
using a 4 changeover output.
In addition, multi-channel relays can be used, whereby one
of the channels is used to switch the load and another
channel is used to return a feedback signal on the switching
status of the output to the upstream control unit.
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Technical appendix/Glossary
W.2 2737920000