Beckhoff TS5066, Руководство пользователя

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PLC API
TS5066 10 Version: 1.0
3 PLC API
3.1 FB_AxisSync
This function block is used for synchronizing NC axes via a network ("distributed axes") and for avoiding
associated beat effects. Internally the function blocks
FB_TimeSync [
}
14] and FB_ExtrapolateAxisValues
[
}
17] are used. These function blocks can also be used individually.
General
When NC axes are synchronized via a network, information from one axis (sender) is typically distributed
cyclically to other axes (receivers) in the form of network variables. If the receivers are operated directly with
the transferred information, beat effects caused by small phase differences in the real-time clocks become
apparent. The beat effects manifest themselves as cyclic disturbance of the receiver axes, since information
may be analyzed twice or skipped, depending on the phase difference. The frequency and duration of the
disturbances depends on the phase difference and the jitter of the individual real-time clocks. Figure 1 shows
the actual velocity of an axis operated directly via a network variable (position interface). The disturbances
caused by beat effects due to step changes in the received set positions are clearly visible.