Siemens Simovert Masterdrives Compendium page 414

Communication / PROFIBUS
Drive configuration
Diagnosis
Times
8.2-84
Configuration of MASTERDRIVES MC:
♦ Enabling the source for clock synchronization by means of P744:
P744.1 P744.2
0 1
1 1
0 0
1 0
♦ With clock-synchronous PROFIBUS it is possible to switch on cycle
monitoring with P723 = 1.
Function: Synchronization telegrams that are received outside the bus
cycle (± 12.8 µs) are ignored.
Advantage: During faulty operation, incorrect and offset
synchronization telegrams are detected and do not cause
synchronization failure.
♦ All tasks to be synchronized have to be in the same time slot,
especially the processing of setpoints and actual values to and from
the CBP2.
Diagnosis of clock synchronization in MASTERDRIVES MC:
♦ B0043 = 1: Application is synchronous with bus clock
♦ r748.9: should fluctuate between 65515 and 20
For further diagnostic parameters, see section "Diagnosis and
Troubleshooting".
The following times will help you when calculating the bus bandwidth
available (12 Mbit/s):
♦ 150-200 µs "Equidistance master cycl. part" per DP slave (cyclical
services master class 1)
♦ Approx. 600 µs for "Equidistance master acyclical part"
(acyclical services master class 1)
♦ Approx. 700 µs for a max. of one additional active node
(master class 2)
♦ 1000 µs computing time for CBP2, parallel to acyclical services
Clock
Equi-master
cyclical
Fig. 8.2-26 Breakdown of the DP cycle at the isochronous PROFIBUS
Synchronization source
First CBP2
Second CBP2
(First SLB)
(Second SLB)
DP cycle
Equi-master
acyclical
CBP2 processing
6SE7087-6QX70 (Version AK)
Compendium Motion Control
09.2008
Clock
Master cl.2
acyclical
Siemens AG
SIMOVERT MASTERDRIVES