
Safety engineering
Safety functions
Ramp monitoring SS1/SS2
45
EDS94AYAF EN 1.0
1.3.6
Ramp monitoring SS1/SS2
The deceleration ramp can be additionally parameterised and monitored for the stop
functions SS1 and SS2 . If the parameterised ramp is not exceeded, the state changes to the
parameterised stop function STO or SOS.
The monitoring of the deceleration process serves to achieve a higher degree of safety.
Ramp monitoring becomes most critical when delay times are caused by high moments of
inertia
ƒ
The application must ensure that the drive is braked to a standstill and the position
is maintained!
ƒ
A safe speed evaluation is the precondition for a safe ramp monitoring, i.e. an
encoder system must be parameterised in the safety module.
ƒ
When ramp monitoring is activated, the starting value of the ramp and the S−ramp
time must be defined in percent.
– The starting value refers to the current speed value at the time of the SS1/SS2
request.
– The starting time of the deceleration ramp is delayed via the S−ramp time in order
to consider a possible S−ramp smoothing.
If the current speed exceeds the parameterised deceleration ramp within the stopping
time or before reaching the tolerance window (n=0), an error message is caused and an
error stop is initiated.
ƒ
The power supply of the motor is immediately safely interrupted (STO). The motor
cannot create a torque and thus no dangerous movements of the drive can occur.
1.3.7
Emergency stop
S
afe
S
top
E
mergency/SSE
The emergency stop function activates STO or SS1. The function to be executed can be set
(C15205). There is no way to avoid emergency stopping during special operation and in
repair mode select (RMS).
With active cascading (C15035), only "STO" is permissible as emergency stop.
Note!
Connect the emergency stop buttons, which must not be overruled by special
operation or repair mode select, to the emergency stop function. For this
purpose, parameterise the safe input as "emergency stop" (C15031).
The emergency stop function can also be requested with SSE bit via the safety
bus.
The activation of the function is reported internally to the standard device and via the
safety bus of the higher−level control.