ABB ACS880-01 Series, Application Manual, Page: 16 / 46

The STO stops the motor (if running) and prevents the motor start. You must select the stop
category according to the system risk assessment.
As an alternative, you can use the FPTC-02 ATEX-certified thermistor protection module,
Ex II (2) GD (L537+Q971) to implement the ATEX-compliant motor thermal protection
function. If you use the FPTC-02 module, it is not necessary to use an ATEX-compliant
protection relay. For more information, see the FPTC-02 user's manual.
Two-channel connection to drive STO terminals
￭ General
This section describes an implementation of the ATEX-compliant motor thermal protection
circuit. The circuit uses the ATEX-certified Safe disconnection function (Q971) of
the drive and a two-channel (redundant) connection to the drive STO terminals.
￭ Implementing the reset of the safety function
A manual reset is mandatory in the motor thermal protection function, if it is required for
ensuring the compliance of the system with Ex/ATEX regulations. After the motor thermal
protection function activates, the motor must not restart before a manual reset command is
given. You can implement a manual reset in the ATEX-compliant protection relay
(recommended). Use the reset button of the relay, or connect an external reset button to
the relay.
In this example, it is also possible to use the STO indication in the drive to implement the
manual reset. See section
Reset method and status indications (page 25) .
￭ Indications of the safety function
In this example, you can use the drive STO indication to indicate the motor overtemperature.
See section
Reset method and status indications (page 25) .
Make sure that this indication generates a fault if the protection relay does not contain a
manual reset.
16 Implementing a motor thermal protection circuit