Siemens SINAMICS S120 - Page 145

Communication via PROFIBUS
Motion control with PROFIBUS
4-145
E Siemens AG, 2004. All rights reserved
SINAMICS S120 Installation and Start-Up Manual, 12/04 Edition
User data integrity
User data integrity is verified in both transfer directions (master <--> slave) by a
sign of life (4-bit counter).
The sign-of-life counters are incremented from 1 to 15 and then start again at 1.
S Master sign of life
– CTW2.12 ... CTW2.15 are used for the master sign of life.
– The master sign-of-life counter is incremented on each master application
cycle (T
MAPC
).
– The number of sign-of-life errors tolerated can be set via p0925.
– p0925 = 65535 deactivates sign-of-life monitoring on the slave.
– Monitoring
The master sign of life is monitored on the slave and any sign-of-life errors
are evaluated accordingly.
The maximum number of tolerated master sign-of-life errors with no history
can be set via p0925.
If the number of tolerated sign-of-life errors set in p0925 is exceeded, the
response is as follows:
–> A corresponding message is output.
–> The value zero is output as the slave sign of life.
–> Synchronization with the master sign of life is started.
S Slave sign of life
– STW2.12 ... STW2.15 are used for the slave sign of life.
– The slave sign-of-life counter is incremented on each DP cycle (T
DP
).
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