Configuring
4-20 Application Module FM 458-1 DP - User Manual
A5E01078222-02 Edition 03.2009
Sampling time
This is the cycle in which the SYNPRO function block and the
transmit- and receive function blocks (on FM 458-1 DP) are
calculated. The sampling time is configured using CFC.
NOTE
Bus circulating time and sampling time are independent of one another.
Synccycle
Synccycle is a multiple integer of the sampling time. It can be
configured at input CNX of function block SYNPRO.
(Synccycle=CNX x sampling time).
A Synccycle always starts with a sampling time. A synchronizing
command is always initiated by the SYNPRO function block in the
system mode at the start of a sampling time.
Configuring version 1 corresponds to most of the applications:
Generating SYNC commands.
The data consistency over all slaves is guaranteed.
The Synccycle is at least twice as long as the 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.
the SYNPRO function block must be configured before all of the
transmit blocks (sequence of execution).
output SOK of function block SYNPRO must be connected with
the enable inputs of all transmit blocks (belonging to a slave
group).
the bus circulating time must be shorter than the Synccycle
minus 1 x sampling time. When operational, it should be checked
as to whether the SOK output goes to “1“ once in each
Synccycle, otherwise the Synccycle should be increased.
Example:
Synccycle=3 x sampling time
Bus circulating time=2 x sampling time
Assumption: The SYNPRO function block calculates at the center of
the sampling time (before all transmit blocks)
Configuring
version 1
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