ABB ACS880-01 Series, Application Manual, Page: 18 / 46

One-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.
• There is a one-channel (non-redundant) connection of the motor protection relay to the
drive STO terminals. Both STO inputs of the drive are connected to same output contact
of the protection relay.
• One output contact of the protection relay is connected to a digital input of the drive.
• The drive shows an overtemperature indication when the digital input switches off (the
protection relay trips).
If you plan to use the one-channel (non-redundant) connection, make sure that you can
reach the necessary safety integrity level (SIL). According to EN 50495, SIL1 is sufficient
for the protection of category 2 and 3 equipment.
Note: The STO function of the drive must always have a redundant connection. See
Connection diagram (page 19) .
￭ 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, you can also configure a manual reset in the drive with the motor
overtemperature or STO indication parameters. See section
Reset method and status
indications (page 25) .
￭ Indications of the safety function
In this example, you can use the drive STO or the motor overtemperature indication. See
section
Reset method and status indications (page 25) .
If you want to avoid parallel indications in overtemperature situations, you can set one or
several of the indication parameters value to
No indication (or None ) or Event :
• the motor overtemperature indication with drive parameters 31.01…31.02 or
35.11…35.12
• the STO indication in the drive with drive parameter 31.22 STO indication run/stop
Make sure that at least one of these indications generates a fault if:
• the protection relay does not contain a manual reset, and
• the FSO module is not configured for an STO manual reset.
18 Implementing a motor thermal protection circuit