Installation manual
PSC1-C-10 Installation manual V2.6
Page 65 of 173
Version: 57E
4.3.2.2
Overview of DC in relation to selected diagnostic functions
Measure
DC
Comment
Usage
Monitoring of outputs by one
channel without dynamic test
0-90%
DC dependent on the switching
frequency
On the usage of elements for
increasing the switching rating
(external relays or contactors),
only effective in conjunction
with readback function for the
switching contacts
Monitoring of
electromechanical, pneumatic
or hydraulic actuators /
outputs
Redundant shutdown path
with monitoring of one of the
drive elements
90%
On the usage of elements for
increasing the switching rating
(external relays or contactors),
only effective in conjunction
with readback function for the
switching contacts
Monitoring of outputs with
direct function as safety
circuit or
monitoring of safety circuits
with elements for increasing
the switching rating or
pneumatic / hydraulic control
valves in conjunction with
readback function for their
switching status
Cross comparison of output
signals with immediate and
intermediate results in the
logic (L) and program execution
monitoring in relation to timing
and logic, and detection of
static failures and short-circuits
(with multiple inputs/outputs)
99%
On the usage of elements for
increasing the switching rating
(external relays or contactors),
only effective in conjunction
with readback function for the
switching contacts
For applications with frequent
demand for the safety
shutdown, testing should be at
short intervals, e.g. at the start
of the shift, 1 x per week.
However, a test should be
undertaken cyclically at least 1 x
per year.
Monitoring of outputs with
direct function as safety
circuit or
monitoring of safety circuits
with elements for increasing
the switching rating or
pneumatic / hydraulic control
valves in conjunction with
readback function for their
switching status
