Retracting; Testing The Measuring Equipment - Siemens Simatic Manual

Fail-safe function blocks for storage and retrieval machines
8. For MAXLOAD_MODE =1, as soon as the value at LOAD1 or LOAD2 exceeds the value pa-
rameterized at MAXLOAD_DYN, then this error is signaled using a 0 signal at
DYN_LOAD_OK.
9. In addition, ERROR is set to 1 and DIAG bit 1 is set
10. As long as one of these errors is active, the velocity parameterized at VMAX_RELEASE is
output at SLS_THRESHOLD.
11. The behavior when MINLOAD is fallen below is equivalent
3.9.3.3

Retracting

12. The block retraction function can be activated using a 1 signal at input RELEASE. Further
travel in the positive direction is then no longer permissible, the block signals this with a 0 sig-
nal at MOVE_POSITIVE_OK. Using an appropriate interconnection with the drive, the user
must ensure that in this case, retraction is only possible downwards.
13. In order to permit retraction, DYN_LOAD_OK or STAT_LOAD_OK is reset to 1 with a rising
edge at RELEASE; using a suitable user interconnection, a drive stop response should then
be deselected.
14. If, while retracting, SAFE_V exceeds the value of SLS_THRESHOLD, then SLS_OK changes
to 0.
15. If, in both cases LOAD1 and LOAD2 are again less than the effective limit - MAXTOL_LOAD,
then ERROR and DIAG bit 1 can be reset to 0 using a positive edge at ACK.
16. The maximum velocity value is again output at SLS_THRESHOLD. (maximum INTEGER val-
ue = 32767)
17. VMAX_RELEASE must lie in the range 1 – 32767; if a value less than 1 is parameterized, the
block identifies this and signals it with DIAG bit No. 8. ERROR changes to 1. 1 is then output
as equivalent value for the retraction velocity.
18. The retraction velocity can no longer be monitored in a safety-related fashion if during retrac-
tion, V_VALID = 0. Therefore, selection using RELEASE = 1 has no effect, and retraction mo-
tion is stopped. DIAG bit 9 as well as ERROR change to 1, a 0 signal is present at SLS_OK.
19. To exit this state, V_VALID must be again set to a 1 signal using F_SAFE_POS by acknowl-
edging.
Safety notes and instructions
The signal for RELEASE must be generated in a safety-related fashion, e.g. by
using a key-operated switch or similar device.
Safety notes and instructions
The parameterization of input V_MAX_RELEASE must be adapted to the permis-
sible safely reduced velocity according to the application-specific risk assess-
ment.
Warning
The interconnection of output MOVE_POSITIVE_OK must match the selection of
the SDI drive function for the positive direction. For MOVE_POSITIVE_OK = 0,
motion must no longer be possible in the positive direction.
The same applies when interconnecting the MOVE_NEGATIVE_OK output – and
inhibiting the negative direction of motion.
It is absolutely essential that the block outputs are connected with the correct
signals for controlling the drive.
Otherwise, an impermissible motion toward the end stops is possible, which can-
not be identified internally by the block.
3.9.3.4

Testing the measuring equipment

20. After the time that can be parameterized at T_INTERVAL expires, the force sensor must be
tested; the block indicates this using a 1 signal at TEST_REQ.
21. The test is started using a positive edge at CALIBRATE, output BUSY changes to 1.
22. Depending on input CAL_MODE, a constant load or a defined load step is expected as test
variable.
S7-Distributed Safety/SIMATIC Safety - fail-safe function blocks for storage and retrieval machines
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