schmersal PSC1 - Page 47

Installation manual
HB-37420-810-01-25F-EN PSC1-C-100 Installation manual - V2.2.docx Page 47 of 201
Version: 25F
For the safety-related assessment of the overall system, it is therefore possible in
principle to use the following diagnostics for the input sensors:
Characteristics
of the input
element
Tests that can be
configured / operative
tests
DC Definition of the
measure
Comment
Cross-circuit test With time monitoring Start test Cyclic test in operation
Single-channel
O O >60
Cyclic test stimulus by
dynamic change of input
signals
An adequately
high test rate must
be ensured
X 90
Cyclic test stimulus by
dynamic change of input
signals
Only effective if
pulse allocation
active
X O O 90-99
Cyclic test stimulus by
dynamic change of input
signals
DC dependent on
frequency of the
start / cyclic test
DC = 90 test only
at intervals > 4
weeks
DC = 99 test at
least 1 x day/ or
100-times
demand rate
Dual-channel
90
Cross monitoring of input
signals with dynamic test if
short circuits are not
detectable (for multiple
inputs/outputs)
With short-circuit
fault exclusion up
to DC=99 possible
O O 90-99
Cyclic test stimulus by
dynamic change of input
signals
DC dependent on
frequency of the
start / cyclic test
X 99
Cross comparison of input
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)
Only effective if
pulse allocation
active
X 99
Plausibility check, e.g. usage
of normally open contacts
and normally closed contacts
= antivalent signal
comparison of input
elements
Only effective in
conjunction with
activated time
monitoring
function for input
element
Options:
X: Diagnostic measure activated
O: At least 1 diagnostic measure activated