User guide

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VTB USER GUIDE
The first one is the “packed” PDO, this PDO will be read from all three slaves for the output state. But how can they
split its own data from the others?
On every slave there is a parameter that specify this information.
As it is displayed in the figures above and showed in fig. 14.17, on every slave there is a parameter (“byte PDO uscite”)
that specify to the devices, where in the PDO data, starts the byte that it have to use. As showed, the first slave, will
have his own data starting from the first byte, the second slave starting from the second byte and so on.
Using this PDO management, we can have only a PDO for 8-byte output block, also on 8 different slaves and not 8
different PDOs, one for each one. It means low net charging.
The real PDO is defined in the first slave, where is the “Fast” mode. In the others, the “Manual” mode, tells to the
device that the PDO
where will be the
data, is already
defined
somewhere, no new
PDO have to be
defined. The Cob-id
have to be inserted
manually as the
same as “fast” PDO.
The parameter tells
to the device, what
are its data within
the PDO.
Therefore the
master will send all
data in one PDO,
that every slaves will
read it and select his own data.
The same thing can be made with the interpolated target quotas. This data is 4-bytes long, then we can have one PDO
with at least 2-devices data inside.
Not all devices supports “packed” PDOs, refer to the devices user manual to verify it.
fOutput byte selection parameter