Overview

SIRIUS 3RA27 function modules for IO?Link or AS-Interface for mounting on 3RT2 contactors

The SIRIUS 3RA27 function modules enable the assembly of starters and contactor assemblies for direct-on-line, reversing and star-delta (wye-delta) starting without any additional, complicated wiring of the individual components. They include the key control functions required for the particular feeder, e.g. timing and interlocking, and can be connected to the control system via either IO?Link or AS?Interface.

The electrical and mechanical connection to the contactor is established by snapping on and locking. An additive protection circuit for the individual contactors can be dispensed with completely because a varistor is integrated in the modules. Feedback from the contactor contacts is performed with Hall sensors which provide reliable feedback concerning the switching state even under extremely dusty conditions.

The starters are connected to the higher-level control system through IO?Link, with the possibility of connecting up to four starters as a group to one port of the IO?Link master,

or optionally via AS?Interface, Specification V2.1 or higher, in A/B technology. As a result, up to 62 starters can be connected to one master and the address is entered in the normal manner with an addressing unit.

Through this type of connection to the control system, a maximum of wiring is saved. In the case of AS?Interface, the wiring amounts to the control supply voltage and the two individual wires for AS?Interface.

The following essential signals are thus transmitted:

• Availability of the feeder in response to an indirect inquiry from the motor starter protector/circuit breaker
• Starter control
• Feedback concerning the switching state of the starter

Signal transmission through IO-Link

Signal transmission through AS-Interface

The inquiry from the motor starter protector/circuit breaker does not take place through additive wiring between the auxiliary switch and the module but by means of a voltage inquiry at the contactor input.

This requires special versions of the contactors with voltage tap-off (see "Power Contactors for Switching Motors" > "SIRIUS 3RT Contactors, 3-pole up to 250 kW").

Availability signal through voltage tap-off

The following benefits result from the use of SIRIUS 3RA27 function modules:

• Reduction of control current wiring. In the case of IO-Link to no more than three cables for four feeders.
• Elimination of testing costs and wiring errors
• Reduction of configuration work
• Parameter server functionality
• Integration into TIA means unambiguous IO-Link diagnostics if a fault occurs
• Dispensing with IO modules saves space in the control cabinet
• All essential timing and interlocking functions for reversing duty and star-delta (wye-delta) starting are integrated
• No additive protection circuit required

For more information on IO?Link and AS?Interface, see "Industrial Communication".

SIRIUS 3RA2711 function modules for IO-Link for mounting on 3RT2 contactors

By grouping up to four starters, it is possible to connect up to 16 starters to one master of the ET 200S or S7?1200. In this case all the signals of the individual controls are made available directly in the process image of the input through only three individual wires per starter group. If the same potential is present at the ET 200S master or S7?1200 and at the switching devices, the wiring can be reduced further by connecting the supply voltage of the contactor coils to the communication wires via jumpers.

Group formation with IO-Link

In case of a malfunction, the corresponding error signals are also sent directly to the PLC in acyclic mode. This is in addition to transmission of the switching signals and status signals.

Possible error signals:

• Switching element defective
• No main voltage (motor starter protector tripped)
• No control supply voltage
• End position right/left
• Manual mode
• Process image fault

This easy integration of the starters in the TIA world does not limit the flexibility in the field in the least. For example, all function modules have special terminals in order to enable direct local disconnection. These terminals can be connected for example to a position switch. The input interrupts the voltage supply to the contactor coil directly, i.e. without going through the PLC. These terminals are jumpered in the as-delivered state.

Local manual operation of the complete starter group is also straight-forward using a hand-held device. The latter is easily connected to the last starter and can be built into the front panel of the control cabinet if required. This offers significant advantages particularly for commissioning.

SIRIUS function modules with IO?Link are used above all in machines and plants in which there are several motor feeders in one control cabinet. Using IO?Link, the connection of these feeders to the automation level is easy, quick and error-free. And with IO modules no longer needed, the width of the PLC is far smaller.

SIRIUS 3RA2712 function modules for AS-Interface for mounting on 3RT2 contactors

Topology with AS-Interface

This easy integration of the starters in the TIA world does not limit the flexibility in the field in the least. For example, all function modules have special terminals in order to enable direct local disconnection. These terminals can be connected for example to a position switch. The input interrupts the voltage supply to the contactor coil directly, i.e. without going through the PLC. These terminals are jumpered in the as-delivered state.

SIRIUS function modules with AS?Interface are recommended above all in machines and plants requiring easy connection of several different sensors and actuators both inside and outside the control cabinet to the higher-level control system. And with IO modules no longer needed, the width of the PLC is far smaller.