One-Channel Connection To Drive Sto Terminals; General; Resetting The Safety Function; Indications Of The Safety Function - ABB ACS880 Application Manual

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 (option +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

Resetting the safety function


A manual reset is mandatory in the temperature protection function, if it is required for
ensuring the compliance of the system with Ex/ATEX regulations. When the protection
relay detects motor overtemperature, the drive must not restart before a manual reset
command. You can implement a manual reset in the ATEX-compliant protection relay
(recommended).
In this example, you can also configure a manual reset in the drive with the motor
overtemperature or STO indication parameters (see section
indications on page 24).

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
If you want to avoid parallel indications in motor 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 (see page 24),
•
the STO indication in the drive with drive parameter 31.22 STO indication run/stop
(see page 24).
Note: Make sure that at least one of these indications generates a fault if the protection
relay does not contain a manual reset.
on page 18.
Implementing a motor thermal protection circuit 17
Reset method and status
on page 24.