ABB DCS8 Series, Original User Manual

Page: 10 / 20

Initial status: The drive is in operation and the motor is at a standstill.
Step Operation
1. The user activates Prevention of unexpected start-up by switching off the POUS
switch [Sxx].
2. The POUS safety relay [A65] trips and the relay switches off the Safe torque off
(STO) control signals on the drive control board [A41]. The STO cuts off the drive
control pulses preventing motor control and generation of torque.
3. The aux. contact of safety relay [A65] energizes the indication lamp [P7x].
4. The motor does not generate torque and remains at zero speed while the POUS is
active.
5. Normal operation resumes after the user:
−
releases the POUS button [Sxx] to normal (up) position
− resets the POUS circuit with the POUS reset button [S7x] (if installed; the user
must push the reset button for 0.1 to 3 seconds)
−
resets the drive (if the STO indication parameter 31.22 has been set so that a
fault is generated)
−
makes sure that the drive has received the start signal (depends on the
configuration, see the firmware manual).
+Q957 Fault reaction function
Definition: A safety function requires a ‘fault reaction function’ that attempts to initiate a safe state if
the safety function's diagnostics detect a fault within the hardware/software that performs the safety
function.
The fault reaction function of the POUS safety relay [A65] trips if it detects a failure (short circuit
between signals, open circuits, redundancy fault) in the safety circuit. The fault reaction function shifts
the drive immediately into the safe state by activating the STO function. The STO function is active until
the fault is repaired. The POUS indication lamp is on until the fault is repaired.
The STO function has its own internal fault diagnostics and fault reaction function.
Parameter settings
This table lists the drive parameters settings for the +Q957 option. For more information, see the
firmware manual.
No. Name Value Description
10.24 RO1 source P.31.98b11 Selects a drive signal to be connected to
relay output RO1. In this case, the RO1 is
energized if the Drive is in STO state and no
STO related fault is active.
31.22
STO indication
run / stop Fault /
Warning Selects which indications are given when
one or both Safe torque off (STO) signals
are switched off or lost, depending on
whether the drive is Running / Stopped,
when they occur. When a fault occurs in the
drive, the mains contactor AC-B or DC-B is
opened by the XSMC-MC relay.
Fault/Warning is the recommended setting.
Use Warning / Warning if E-Stop, stop
category 0 (+Q951 or +Q563) is used.