5.1.2
Dynamization
Brief description
Dynamization is to detect static error states in the safety-relevant circuits.
In the case of selection via an active or passive safety unit, dynamization
takes place automatically in the background without having an effect on the
safety function or the standard drive functions.
It is not necessary to configure the dynamization at the drive.
Functional principle of dynamization
A safety function is selected via an N/C‑N/C combination, i.e. a "0" signal at
both inputs is evaluated when the safety functions are selected. Therefore,
the dynamization of the external selection channels can only take place in the
deselected state (normal operation).
Dynamization in the case of selec‐
tion via an active safety unit
An active safety unit is a safety switching device which selects the
safe function via OSSD outputs. The active safety unit tests its
outputs on its own.
The "OSSD" (Output Signal Switching Device) is that part of a
safe selection unit which has been connected to the machine
control and which goes to the OFF state, if the safe selection unit
triggers during the intended operation.
When the safety functions are selected via an active safety unit, the
dynamization pulses of the OSSD outputs of the active safety unit are
evaluated and monitored. Therefore, other dynamization signals are not
required.
The active safety unit must detect the following errors via its OSSD outputs:
●
Short circuit of one or both selection signals with 24 V
●
Short circuit between both selection signals
In order that all other relevant errors can be detected by the optional safety
technology module "T0", the dynamization pulses of the OSSD outputs must
comply with the following limit values:
Description
Value
Explanation
t
PLmax
3 ms
Maximum low time of the test pulse
t
PLmin
100 µs
Minimum low time of the test pulse
t
Pmax
1 h
Maximum periodic time of the test pulses
t
Pmin
1 ms
Minimum periodic time of the test pulses
t
Vmax
1 s
Maximum delay of the selection signals
for selection or deselection
t
Dmin
= t
PH
/ t
P
90 %
Minimum sampling ratio of the selection
signals
t
bounce
400 ms
Maximum bounce time for a selection or
deselection
φ
-
Phase shift of the test pulses on both
channels: no requirement
Tab. 5-1:
Limit values of the dynamization pulses of the OSSD outputs
24/65
Functional principle of integrated safety technology
ctrlX SAFETY "Safe Torque Off" Safety Option in ctrlX DRIVE
Bosch Rexroth AG R911383774_Edition 03
