Configuring
Application Module FM 458-1 DP - User Manual 4-21
A5E01078222-02 Edition 03.2009
Sampling time
Synczyklus
Bus circulating
time
Output SOK
1
0
(1) (2) (3) (1) (2) (3)
SYNC_command
SYNC_quit
SYNC_command
SYNC_quit
SYNC_command
Fig. 4-6 Timing diagram, SYNC version 1
When initiating the SYNC command, the transmit blocks are inhibited
(SOK=0) for two sampling times (one bus circulating time). The transmit
blocks are enabled in the third sampling time after initiating the SYNC
command (SOK=1).
Configuring version 2 has the highest SYNC performance:
Generating SYNC commands.
The data consistency over all slaves is guaranteed.
Synccycle=sampling time (CNX=1)
the length of the transmit telegrams (outputs) for each slave may
not be greater than 32 bytes.
all transmit blocks and the SYNPRO function block must be
configured in the same sampling time.
high baud rate (>1.5 Mbaud). For lower baud rates, the time
conditions can hardly be maintained.
the bus circulating time may only be a maximum of 50 % of the
sampling time.
the bus circulating time must also be so low, that one sampling
time expires from the start up to the calculation of the function
block SYNPRO. This cannot be guaranteed, but must be checked
when the system is operational.
Example:
Synccycle=sampling time
Bus circulating time=0,3 x sampling time
Assumption: The SYNPRO function block calculates at the center of
the sampling time (before all transmit blocks)
Configuring
version 2
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