Control elements
© Siemens AG 2003 All Rights Reserved
SIMOTION Safety Unit (AP) - Edition 06.2003
4-29
4.1.1
Determining the safety distance
The reaction times of the control unit and the machine must be considered when
determining the safety distance. The reaction time and the resulting safety distance
can be calculated using the following equation:
S = (T
2
+ T
3
) * v
g
S: Safety distance
T2: Reaction time of control unit
T3: Reaction time of machine
vg: Activation time (1.6 m/s according to EN 999)
Example:
T
2
according to Safety Unit data sheet
connection of the lag meter for determining
the reaction time of the machine (empirical
T
3
measurement)
use the poorest of 10
measurement values!
Control unit
Machine
