Siemens SIRIUS 3SK1

6.3 System con󹪝guration rules
General information
• All basic units can be operated as a stand-alone device without a device connector.
• 3SK1220 input expansions and the 3SK1230 power supply must always be connected on the
left of the basic unit and output expansions (3SK121 and 3RM1 Failsafe motor starters) on
the right.
Expansion on the input side
• If an (additional) input expansion is detected on the left when the basic device or an input
expansion powers up, it will be loaded into the device con󹪝guration.
• An input expansion evaluates the sensor states and generates an enable signal for the basic
unit depending on the start condition. The enable signal is then acquired by an input
expansion on the right-hand side, or acquired by the basic unit and ANDed with its sensor
statuses.
You can 󹪝nd information on the start characteristics in the system con󹪝guration of the 3SK1
Advanced in the chapter "Explanation of the device’s function (Page 176)".
• The 3ZY12 device connector used below the 󹪝nal device must be 󹪝tted with a cover on the
left side (included with the device termination connectors).
• A 3SK1230 power supply can also be used in the 3SK system. This 3SK1230 power supply
must always be plugged into the system on the extreme left.
• No more than one 3SK1230 power supply is admissible for each system.
• If a 3SK1230 power supply is used, no additional, external 24 V DC voltage is permitted to be
connected to a basic unit.
Output expansion
• If an output expansion is detected on the right when the device powers up, this will be loaded
into the device con󹪝guration. The internal feedback circuit of the contact extension is
evaluated and checked.
• If both the 3SK1211 / 3RQ1 output expansion and 3RM1 Failsafe motor starters are used in
a system, the 3RM1 Failsafe motor starters must be positioned on the right of the 3SK1211 /
3RQ1 output expansions.
• If a 3SK1213 output expansion is used in the system, this must always be the 󹪝nal station in
the system (on the right) and must be 󹪝tted with a 3ZY1212-0FA01 device termination
connector. Only one 3SK1213 output expansion can be used in the system with a device
connector; further 3SK1213 output expansions can be optionally interfaced by wiring.
• On the 3SK121 output expansions, a slide switch on the device front must be used to set
whether the (UNDELAYED) or (DELAYED) output signal of the basic unit is to trigger a
response. If a purely instantaneous 3SK112 basic unit is used, the slide switch MUST be set
to the (UNDELAYED) position.
The 3RQ1 output expansions do not have a slide switch and always react to the (UNDELAYED)
output signal.
System con󹪝guration
6.3 System con󹪝guration rules
SIRIUS 3SK1 Safety Relays and 3RQ1 Positively-Driven Coupling Relays
120 Equipment Manual, 05/2021, A5E02526190021A/RS-AE/005