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7
Functional principle
7.1
Dynamization
7.1.1
Brief description
The dynamization is to detect static error states in safety-relevant circuits, e.g.
end stage switch-off, brake control, local output as well as in the external
wiring.
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 in the drive.
7.1.2
Functional principle of dynamization in the selection signals
Depending on the required safety integrity level and the number of selection
channels, fields have to be excluded from external wiring or have to be shown
in case discrete selection is used.
If errors caused by dynamization of the selection signals, so-called dynamiza-
tion pulses, have to be detected, this has to be realized in connection with the
optional safety technology modules by the selecting safety unit.
The discrete selection of safety functions at the local input configured as "safe
input", is realized via an N/C-N/C combination in case of dual-channel selection.
Two or a "0" signal at the inputs indicates a selection of the safety functions,
a dynamization of the external selection channels can only take place in dese-
lected state.
Dynamization in the case of selection 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.
"OSSD" (Output Signal Switching Device) is the part of a safe selection unit
which has been connected to the machine control and which changed 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 dynamiza-
tion pulses of the OSSD outputs of the active safety unit are evaluated and
monitored.
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 the selection signals
An evaluation of the dynamization pulses on the optional safety technology
module does not take place. The dynamization pulses are filtered out by the
optional safety technology module. The maximum length of the dynamization
pulse can be configured (refer to
The figure below schematically illustrates the interconnection of an active
safety unit and multiple drives with an optional safety technology module:
R911404905, Edition 02
ctrlX SAFETY "SafeMotion"
⮫ Signal control of
inputs).
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Dynamization
Bosch Rexroth AG
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