Safety Integrated - Industry - Siemens

■ This circuit principle is suitable for selectively shutting
down several drives. Protective door 1 acts on drive A, protective
door 2 on drives A and B, protective door 3 on drive
B. When the internal safety relay of the drives functions correctly,
line contactor K1 does not drop-out (also refer to the
block diagram above). The following table shows how the
two drives A and B are dependent on the state of the protective
doors.
Behavior when Emergency Stop is issued
Emergency Stop is initiated using button S9 ("Emergency
Stop"). This initiates that the drives are shut down according
to stop Category 1 in compliance with EN 60204-1.
■ A 0 signal is entered at contacts X101.X (OFF3) of the drive
via the enable contact of safety combination A4. The drives
are immediately braked down to 0 speed and the pulses
cancelled. At the same time, the drop-out delay of time
relay K2a/b and the delay time of the safety combination
A4 are started. The drives must have come to a standstill
before these delay times have expired.
Behavior when the protective doors are opened
When protective doors 1-3 are opened, it is initiated that the
associated drives are shut down according to stop Category 1
in compliance with EN 60204-1. It must be ensured that potentially
hazardous motion must have come to a standstill before
a person can reach the potentially hazardous area!
■ A 0 signal is entered at contact X101.X (OFF3) of the
drive/drives via the enable contact of the safety combinations
A1, A2 or A3. The drives are immediately braked
down to 0 speed and the pulses cancelled. At the same
time, the drop-out delay of time relays K2a and/or K2b are
started. The drive/drives must have come to a standstill
before these delay times have expired.
■ After the drop-out delay time of time relay K2a/b has
expired, the internal safety relay of the drives are no longer
energized (1st shutdown path!).
Drive A Drive B
Protective door 1 open Safe standstill Ready
Protective door 2 open Safe standstill Safe standstill
Protective door 3 open Ready Safe standstill
■ After the drop-out delay time of time relay K2a/b has
expired, the internal safety relays of the drives are no
longer energized (1st shutdown path!).
■ After opening the safely delayed enable contact of safety
combination A4, line contactor K1 is no longer energized
and the drives are electrically isolated from the line supply
(2nd shutdown path!).
■ The checkback signal of line contactor K1 is monitored in
the on circuit of safety combination A4. If the contactor
does not drop-out due to an incorrect function, then the
drive is prevented from restarting after an Emergency Stop.
■ Before the selected delay times of safety combinations A1-
3 expire, the internal safety relays of the drives must have
already dropped-out. Their checkback signal contacts
X533.1/2 indicate that the drives are in a safe condition.
■ After the selected delay time has expired, the safely
delayed enable contacts of the safety combinations open.
■ When the internal safety relays of the drives function correctly,
their checkback signal contacts X533.1/2 are closed,
line contactor K1 does not drop-out.When an internal
safety relay does not function correctly, its checkback signal
contacts X533.1/2 are not closed and line contactor K1
drops-out (2nd shutdown path!).
Functional Example No. MC-FE-I-001-V11-EN 409
Ex. No.
1.7