Manual VIPA System SLIO
Chapter 3 Deployment
HB300E - IM - RE_053-1CA00 - Rev. 11/29
3-21
The parameter "PDO transmission type" fixes how the sending of the
PDOs is initialized and what to do with received ones:
Transmission Type
Cyclical
Acyclical
Synchronous
Asynchronous
0
x
x
1-240 x
x
254, 255
x
The transmission type 0 is only wise for RxPDOs: the PDO is analyzed at
receipt of the next SYNC telegram.
At transmission type 1-240, the PDO is send res. expected cyclically: after
every "n
th
" SYNC (n = 1 ... 240). For the transmission type may not only be
combined within the network but also with a bus, you may thus e.g. adjust
a fast cycle for digital inputs (n = 1), while data of the analog inputs is
transferred in a slower cycle (e.g. n = 10). The cycle time (SYNC rate) may
be monitored (Object 0x1006), at SYNC failure, the coupler sets its outputs
in error state.
The transmission types 254 + 255 are asynchronous or also event
triggered. The transmission type 254 provides an event defined by the
manufacturer, at 255 it is fixed by the device profile.
When choosing the event triggered PDO communication you should keep
in mind that in certain circumstances there may occur a lot of events
similarly. This may cause according delay times for sending PDOs with
lower priority values.
You should also avoid to block the bus by assigning a high PDO priority to
an often alternating input ("babbling idiot").
Via the parameter "inhibit time" a "send filter" may be activated that does
not lengthen the reaction time of the relatively first input alteration but that
is active for the following changes.
The inhibit time (send delay time) describes the min. time span that has to
pass between the sending of two identical telegrams.
When you use the inhibit time, you may ascertain the max. bus load and
for this the latent time in the "worst case".
PDO transmission
type
Synchronous
Asynchronous
Inhibit time
