SIEMENS
5/43
Siemens IC 10 · 2017
Coupling Relays
LZS coupling relays with plug-in relays
5
■
Overview
Coupling relays with plug-in relays can be ordered as complete
units or as individual modules for customer assembly.
Function
The coupling relays with semiconductor output have low power
consumption and are therefore particularly well suited to solid-
state systems. In the versions equipped with LEDs, these indi-
cate the switching state. The LZS:PT/MT coupling relays have a
test button. This can be used to force the relays into the switch-
ing state and to lock it without electrical control. This is indicated
by a raised petrol-colored lever.
Control with solid-state output
In the case of solid-state outputs (e.g. proximity switch) with
overload and short-circuit protection, you must make allowance
during configuration for the temporarily flowing capacitor
charging currents! This is possible, for example, by using a
suitable LZS coupling relay with plug-in relay.
Surge suppression
The 24 V DC relays LZX:RT and LZX: PT with LEDs can be
supplied with, all others without integral surge suppression
(freewheel diode connected in parallel with A1/A2). The positive
control supply voltage must be connected to coil terminal A1.
Mounting
The relays are plugged into the base and this is snapped onto a
TH 35 standard mounting rail according to IEC 60715.
A fixing bracket can be ordered for the MTseries that addition-
ally fixes the relay into a plug-in base (under conditions of
increased mechanical stress). For the RT and PT series, a com-
bined fixing and ejection bracket is available which can be used
to disassemble the relay where access is difficult, for example,
when relays are mounted side-by-side.
They can be mounted as required.
Logical separation
The terminals for the contacts and the terminals for the coil are
arranged on separate levels, e.g. above for contacts and below
for coil. Logical separation is not necessarily protective
separation.
Protective separation
For protective separation, transfer of the voltage of one circuit to
another circuit is prevented to a suitable degree of safety
(requirements and tests are described in IEC 60947-1 in
Appendix N).
Notes on the previous LZX series
The complete units and accessory parts of the LZX series are no
longer listed in this catalog. The complete units of the LZS series
are fully compatible with the corresponding units of the
LZX series. Prices for the LZS series are lower than for the
previous LZX series.
The LZX plug-in relays are available unchanged and are used
accordingly in both the LZS and the LZX series.
Note:
Due to differences in geometry, the LED modules, plug-in bases,
fixing brackets and labels can be combined and/or used only in
the respective series, LZS or LZX.
The LZS series offers not only service-proven screw connections
but also versions with plug-in terminals (push-in).
© Siemens AG 2016