Phase-out/discontinuation of SIRIUS 3TX7 coupling relays

The phase-out period for SIRUS 3TX7 coupling relays began in September 2015. The devices will no longer available for ordering as from October 1, 2018. We therefore recommend that you do not delay in ordering the successor generation of coupling relays, SIRIUS 3RQ3!

The old devices can be replaced with devices from the new generation without restrictions. Our conversion tool is available for old and new as well as competitor conversions, see http://www.siemens.com/sirius/conversion-tool.

If any further questions arise during your conversion activities, please do not hesitate to contact our Technical Assistance, either via telephone on +49 (911) 895 5900 or via email at  .technical-assistance@siemens.com.

For more information, see SIRIUS 3RQ3 coupling relays and/or http://www.siemens.com/relays.

SIRUS 3TX7 coupling relays in narrow design are used to connect control signals to and from a PLC and are available in several different versions:

• Coupling relays with relay output
• Coupling relay with plug-in relay
• Coupling relays with semiconductor output

Coupling relays with relay output

AC and DC operation

IEC/EN 60947‑5‑1

In the coupling relays in double-decker design, the connections are arranged on two levels; these units are extremely compact. Connection method: screw or spring-type terminals. For test purposes, versions are available with manual-0-automatic switches.

The input and output coupling relays differ with regard to the positioning of the terminals and the LED. For equipment identification purposes, each coupling relay has a blank labeling plate.

The coupling relays with relay outputs have a low power consumption and are therefore particularly well suited for solid-state systems.

Application example: Motor control

Surge suppression

The coupling relays have been tested in 1 x 10⁵ operating cycles under AC-15 operation with the values specified in the technical specifications.

The endurance of the coupling relays can be increased by connecting inductive loads.

Note 1:

If capacitive loads are switched without components (series resistors) that limit temporary peak currents, microscopic welding of the relay contacts may result.

Note 2:

For operation with rated voltage and 100% ON period 24/7, always ensure a distance of at least 10 mm between modules or any adjacent contacts.

Coupling relay with plug-in relay

AC and DC operation

IEC 60947-5-1, EN 60947-5-1

Coupling relays are used to couple signals to and from a PLC. The relays are of plug-in type, meaning that at the end of its service life it can be replaced without disconnecting the wiring. For replacement modules see "More information".

For easy linking of the signals, each terminal can be jumpered using an external connecting comb.

Advantages:

• Coupling relays in 6.2‑mm width with screw or spring-type terminals
• Fast exchange with permanent wiring (plug-in relay)
• Tested complete units в†’ lower assembly time
• Single relays available as components
• The wire inlet and connections can be accessed from the front. This results in faster wiring time and wiring errors are prevented.
• Linking of control supply voltage and control signals with 16-pole connecting comb
• Galvanic isolation plate for isolating different voltages for neighboring units
• Integrated reverse polarity protection and EMC arc-suppression diode
• Functional state of the coupling relay clearly indicated by yellow LED
• Safe isolation according to IEC 61140
• Device variants with hard gold-plated contacts, hence high contact reliability
• 230 V AC/DC versions available

Note 1:

The endurance of the coupling relays can be increased by connecting inductive loads. Capacitive loads can result in micro-welding on the contacts.

Note 2:

For operation with rated voltage and 100% ON period 24/7, always ensure a distance of at least 10 mm between modules or any adjacent contacts.

Coupling relays with semiconductor output

AC and DC operation

EN 60947‑1, EN 60664‑1 and EN 50005;
Coupling relays with semiconductor output: EN 60747‑5;
programmable controllers: IEC 61131‑2

The input and output coupling relays differ with regard to the positioning of the terminals and the LED. For equipment identification purposes, each coupling relay has a blank labeling plate.

The coupling relays with semiconductor outputs have a low power consumption and are therefore particularly well suited for solid-state systems.

In the coupling relays in double-decker design, the connections are arranged on two levels; these units are extremely compact. Connection method: screw or spring-type terminals. For test purposes, versions are available with manual-0-automatic switches. This version is also available with spring-loaded terminal connections.

Application example: Motor control

Surge suppression

In the case of coupling relays with semiconductor output (optocouplers), the contact element is a semiconductor. These are not subject to wear; so welding is not possible.

Note:

With semiconductors, the switching current is not dependent on the inductance of the load, i.e. the switching current for an inductive DC-13 load is the same as that for a DC-12 load. This means that coupling relays with a semiconductor output are particularly suitable for inductive loads, such as solenoid valves. It is not relevant to specify the number of operating cycles because this does not affect the lifetime of the semiconductor, provided it is not overheated.