Position And Velocity Monitoring - Siemens Simatic Manual

Fail-safe function blocks for storage and retrieval machines
V
V_MAX
0
X_NEGATIVE
0 SLU
The block identifies if not all of the mentioned preconditions are satisfied, and this is signaled as
parameterizing error with the appropriately set DIAG bits.
Safety notes and instructions
The user must validate the parameterized envelope curve himself, and must verify
the correct functionality using the appropriate traces and tests (see Chapter 3.1.1).
Note
Requirements regarding the monotony and gradient of the envelope curve de-
pend on the specific application and on the risk assessment.
Note
The block only checks the parameterization at the 1st call. This results in a sub-
sequent increased block performance.
As a consequence, reparameterization is not permitted when safety operation is
deactivated. The safety program must be regenerated and loaded each time that
any of the block operating parameters are changed.
3.6.3.2

Position and velocity monitoring

8. As long as the position actual value is valid and SAFE_V lies below the parameterized velocity
envelope curve, the block does not signal an error i.e. outputs ERROR and DIAG supply a 0
signal.
9. Dependent on SAFE_POS, the associated maximum permissible velocity for this position is
output at SLS_ THRESHOLD.
10. If the value at input SAFE_V lies above this limit, and if the system moves towards the end
stop, then output SLS_OK is set to 0, ERROR changes to 1, and DIAG bit No. 9 is set.
Depending on the user interconnection, a stop response must be initiated in the drive.
11. As soon as SAFE_V returns to the permitted range, i.e. less than the SLS_THRESHOLD, the
error can be acknowledged and a 1 signal is output at ACK_REQ.
12. The error can be reset with a positive edge at ACK. ERROR and the corresponding DIAG bits
then change back to 0, and SLS_OK again has a 1 signal.
13. If the value at input SAFE_V lies above the permitted velocity, but the system moves away
from the end stop, the axis may travel with 100% of velocity, V_MAX is output at
SLS_THRESHOLD. As a consequence, no error is signaled here, ERROR and DIAG remain
at 0.
14. If a 0 signal is available at POS_VALID, then DIAG bit 5 is set, until acknowledgment, ERROR
remains in the actual state, assuming that no additional faults/errors occur as a result of an-
other active monitoring function. All other outputs maintain their actual state until acknowl-
edgment, or the cancellation of RELEASE
S7-Distributed Safety/SIMATIC Safety - fail-safe function blocks for storage and retrieval machines
remaining distance Max (9999 SLU)
.
X
X_POSITIVE
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