Ss1 Stop Category 1 For Several Power Units; Description - Siemens SINAMICS DCM User Manual

SS1 stop Category 1 for several power units

8.1

Description

When selecting the safety function (actuating the EMERGENCY STOP mushroom
pushbutton), the instantaneous NO contacts are immediately opened in the
3SK1122-2CB4x
initiated at the SINAMICS DCM "Master Unit" via the programmable digital input DIO4
(X177.15). The drive is braked along a ramp that can be adjusted using p50269. The down
ramp is not monitored.
As soon as the SINAMICS DCM identifies that the motor is at a standstill (speed of 0), the
firing pulses are inhibited and the power disconnected.
Independent of the down ramp that has been adjusted, after the time set at the safety relay,
the delayed contact of the safety relay is opened. These contacts initiate the E-Stop function
at all of the SINAMICS DCM units.
The SINAMICS DCM units reduce the armature current, inhibit the firing pulses and open the
armature contactor. The "E-Stop active" signal must be integrated in the feedback circuit of
the safety relay via a coupling relay at digital output DO3 (X177.22).
At the same time when the NO contacts of the safety relay open, the safety-related output
expansion 3SK1211-2BB40 is shut down via the internal communication of the 3SK safety
relays; as a consequence, the safety-related coupling relays to control the armature and field
circuits are opened.
The motor current therefore goes to zero and in turn, the motor torque also goes to zero. If
zero speed has still not been reached, then the motor coasts down.
The drive system can only be considered to be in a torque-free state after the delay time has
expired and the power switching devices opened.
Up to 6 SINAMICS DCM units can be connected in parallel or series. For all units, the E-
Stop terminals - as well as the armature contacts - must be integrated via safety relays. This
is realized with the additional safety-related output expansions 3SK1211-2BB40.
In the circuit examples, the energy feed to the field power units as well as to the armature
circuit is interrupted. Controlling the field contactor is optional. However, in this case, the
motor cannot be considered to be in a no-voltage condition.
Note
For setting p50269=0 (OFF3 ramp down time), the drive brakes at the current limit. The
actual ramp-down time is influenced by the driving forces of the mechanical system. The
safety relay delay should be set longer than the actual ramp-down time.
(x) order code for the time delay:
1
1 = 0.05 ... 3 s
Application document for functional safety STO, SS1 (ISO 13849-1)
Compact User Manual, 09/2016, A5E34871844AM
safety relay, which immediately causes the OFF3 function (fast stop) to be
1
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