Programming / parameter assignment
Instruction Manual PROTECT-PSC
V 2.6R01 / 04.19
6-34
Description
Markings
As the PROTECT-PSC can also be used for control tasks that are not safety-
oriented, all ladder diagram symbols in the PS program (contact, coil, timer … )
have a marking to show the programmer which symbols may be used for safety
functions.
Marking
Safe
Description
“U”
no
A safe symbol was overwritten by a non-safe symbol. The
symbol is not safe and may not be used for safety functions.
“ ”
no
Symbol is not safe and may not be used for safety functions.
“S”
yes
Symbol is safe and may be used for safety functions.
“S2”
yes
Symbol ist safe in accordance with the requirements of cat. 2
and may be used for safety functions.
T
T
a
a
b
b
l
l
e
e
6
6
-
-
3
3
M
M
a
a
r
r
k
k
i
i
n
n
g
g
s
s
o
o
f
f
t
t
h
h
e
e
l
l
a
a
d
d
d
d
e
e
r
r
d
d
i
i
a
a
g
g
r
r
a
a
m
m
s
s
y
y
m
m
b
b
o
o
l
l
s
s
In order to find the cause of a ‘U’ mark more easily, these are highlighted in two dif-
ferent background colours
RED
appears in the line containing the cause of the ‘U’ mark.
YELLOW
appears in the line that contains a ‘U’ mark due to an existing
‘U’ mark.
The symbol marking is performed in accordance with a system of rules of which the
main rules are described in the following.
The observation of the rules is ensured by PROTECT-PSCsw and need not be un-
derstood by the programmer in all cases. However, an understanding makes it
easier for the planning/programming in advance to attain the desired safety.
1.
Inverted inputs (B contact) are
not safe
and are marked
‘ ’
.
2.
Self-holding (activation by own state) is
not safe
and marked with
‘ ’
.
3.
A parallel connection (OR operation) from one or more
‘S’
or
‘S2’
and at
least one
‘ ’
or at least one
‘U’
produces a
‘U’
.
4.
A branch containing a
‘U’
(direct or indirect) always gives rise to a
‘U’
.
5.
A series connection (AND operation) from
‘ ’
and at least one
‘S’
produces
an
‘S’
or an
‘S2’
.
For safety-oriented control tasks only ladder diagram symbols to switch outputs
marked with an ‘S’ or an ‘S2’ may be used. This information does not relieve the
programmer of the responsibility to carry out his own evaluation of the user pro-
gram.
The ‘S’ or the ‘S2’ mark does not made any declaration about the reached SIL,
Cat. or an PL. Therefore the combination of Sensor - PROTECT-PSC
– Actor un-
der provision of the PROTECT-PSC Application program must be taken in consid-
eration.
Summary of Contents for PROTECT-PSC
Page 4: ......
Page 8: ......
Page 112: ......
Page 132: ......
Page 252: ......
Page 265: ...Annex 8 Instruction Manual PROTECT PSC V 2 6R01 04 19 8 5 8 3 EC Type Examination certificate ...
Page 266: ...Annex 8 Instruction Manual PROTECT PSC V 2 6R01 04 19 8 6 8 4 Declarations of conformity W ...
Page 267: ...Annex 8 Instruction Manual PROTECT PSC V 2 6R01 04 19 8 7 8 5 Index ...
