Ss1 Delay With S-Ramp Stop Profile - Danfoss VLT MCB 150 Operating Instructions Manual

Functions and System Overvi...
Safe Torque Off is activated immediately when the
configured Stop Delay has expired, regardless of speed,
see chapter 6.1 Configuration for parameter settings.
Selecting the SS1 settings
1. Enter 42-41 Ramp Profile
3 3
2. Select
2a
2b
By using SS1 Delay, the frequency converter attempts to
follow the selected ramp. After a specified delay time, Safe
Torque Off is activated and the motor is made torque free.
CAUTION
Using SS1 Delay may result in the motor still spinning
when the Safe Torque Off is activated. The risk analysis
for the machine must indicate that this behaviour can be
tolerated. An interlock may be required.
Default value in 42-40 Type is [0] Delay. If this value is
selected, the Safe Stop 1 function activates a braking ramp
defined from a selected time delay in 42-42 Delay Time.
This means that the braking ramp is linear. Select the value
of 42-43 Delta T (the % of the delay time), which is a
reasonable tolerance after the SS1 Delay Time has expired.
NOTICE
The SS1 delayu function does not monitor the stopping
of the frequency converter!
The safety relevant time, Delta T, allows the frequency
converter to come to a stop before Safe Torque Off is
activated. Thus ensuring that the system is also stopped
before Safe Torque Off is activated. If a fault occurs, the
frequency converter does not come to a stop. It coasts
after the time delay no matter of the speed of the
frequency converter.
16
Operating Instructions
[0] Linear, if the ramp must follow a
linear curve
[2] S-ramp Const Time, if the ramp
should follow an S-ramp
Danfoss A/S © Rev. 2014-02-11 All rights reserved.
A
1
3
A Actual frequency
1 Activation of SS1 Delay Timer
2 Activation of Safe Torque Off
3 42-42 Delay Time
4 42-43 Delta T
Illustration 3.7 SS1 Delay
When Safe Stop 1 function is active, the frequency
converter brings the motor to zero speed. The Safe Torque
Off function is triggered after a specified safety-relevant
time. This safety function corresponds to a controlled stop
of the frequency converter according to EN IEC 60204-1,
stop category 1.

3.5.4.2 SS1 Delay with S-ramp Stop Profile

An S-ramp gives non-linear deceleration, compensating for
jerks in the application.
1. Define a speed profile by a delay (a "worst case"
delay from actual frequency to zero speed) and a
delay tolerance. The safety relevant time, Delta T,
allows the frequency converter to come to a stop
before Safe Torque Off is activated. Thus ensuring
that the system is also stopped before Safe
Torque Off is activated. If a fault occurs, the
frequency converter does not come to a stop. It
coasts after the time delay regardless of the
frequency converter speed.
2. Define an S-ramp configuration, which achieves
zero speed within the delay.
time
4
2
MG34W302