Safety Integrated - Industry - Siemens

Ex. No.
12 Network 1 to 4
In these networks, the value of the speed determined by
PROFIBUS is formed (N_PB -> N_PB_POS). This value is required
further. The speed value determined via the count
module of ET 200S is always positive.
Network 5 to 7
In these networks the plausibility checks whether the actual
speed value determined with PROFIBUS and the actual speed
value determined with the ET 200S count module are deviating.
First, the difference SUB_RES is formed of both determined
values (NW5). This difference is in NW7 compared with
the tolerance value N_DIFF. If the difference is outside this
tolerance value, this is interpreted as error. In this case
N_ERR2=1 which, if "safe speed" (SG) mode is set, causes a
safe drive shutdown.
390 Functional Example No. AS-FE-I-012-V10-EN
Network 8
In this network it is checked whether the actual speed value
exceeds the limit value N_MAX. In this case N_ERR1=1 which
in "safe speed" (SG) mode causes a safe drive shutdown.
Network 9
In this network the safe standstill is defined.
Note
When determining the standstill, the drive speed
(here: N_PB_POS and N_COUNT) is not compared
with 0, but with N0_TOL (here: 2). This takes into
account, that the incremental shaft encoder can also
detect speeds not equal to 0 due to small movements
of the drive. On average, however, the speeds are 0.
The comparison value must be adjusted to your individual
situation.
The switch-on delay CHECK_TON becomes 1
■ if the drive is not in standstill AND
■ the time parameterized at PT has elapsed.
In case of an error at CHECK_TON =1 during plausibility check
in "safe speed" (SG) mode, the drive is switched off safely.
Without the switch-on delay CHECK_TON the drive would stop
after switching on, as due to the inertia of the mechanical
contacts, the plausibility conditions at times t