Time delay filter

A time delay filter delays signals in time without changing the signal curve. One application, for example, is to compensate for dead times in the drive train, if this is not identical in all axes.

The delay time can be configured in axes either in cycles in the parameter order (P-AXIS-00587) or in µs in the parameter order_time (P-AXIS-00591). Alternatively, it is also possible to program delay time in the NC program parameters ORDER or ORDER_TIME. The maximum number of possible delays is 100 cycles or 100* NC cycle time in µs.

Another possible application is to synchronise axes when FIR filters are used.

If a FIR filter is used in only one axis and not in the other axes of an axis group, the axes will run asynchronously in time. To obtain synchronous axes despite this, time delay filters can be used in the other axes.

Programing Example

Time delay filter to synchronise axes

Axis with configured moving average filter:

filter_fir.enable              1

filter_fir.type                1 (moving average filter)

filter_fir.order               20

filter_fir.share               100

Required settings in other axes to obtain synchronous axes:

filter_fir.enable              1

filter_fir.type                4 (time delay filter)

filter_fir.order               10

filter_fir.share               100

The adjusting filter order of the time delay filter is obtained from half the filter order of the filter used:

filter_fir.order / 2

If the filter order is an odd number, the adjusting filter order of the time delay filter is obtained from:

(filter_fir.order+1 ) / 2