In the combined up/down counting modes there are 7 hardware preset modes which are combinations relating to states and/or edges of Ipres ST_IPRES (%IWr.m.c.2.3) and IZ ST_IZ (%IWr.m.c.2.6) physical inputs:
-
IPres rising edge,
-
IPres falling edge,
-
rising edge of IPres + direction / falling edge of IPres - direction,
-
rising edge of IPres - direction / falling edge of IPres + direction,
-
status of IPres,
-
reference point short cam (with incremental encoder),
-
reference point long cam (with incremental encoder).
Direct preset DIR_PRES (%Qr.m.c.1) (by software) exists alongside the hardware presetting modes mentioned above.
The first two presetting modes (on IPres rising or falling edge) are the same as those described for down counting only.
The figure below shows an example of preset on the
IPres rising edge, as well as direct (software) preset. Preset on the
IPres falling edge is similar. The associated language objects are described in the
implicit objects section.
Preset on IPres edge combined with counting direction
The figure below shows an example of preset on the rising edge of IPres in up counting (+ direction), and on the falling edge of IPres in down counting (- direction). The reverse case is similar.
The figure below shows an example of preset on IPres state (high level). The counting value is fixed at the preset value for the duration of the active state of IPres.
Preset on reference point short cam
This mode and the one that follows (reference point long cam) are to be used with an incremental encoder.
The time diagrams below show preset mode on a reference point short cam .
NOTE: (1) preset is taken into account:
-
in + direction (up counting): IPres input at state 1, rising edge of marker input at IZ ST_IZ (%IWr.m.c.2.6) revolution and software enabling.
-
in direction - (down): IPres input in state 1, falling edge of marker input at IZ revolution and software enabling.
NOTE: In principle, as the short cam is less than an incremental encoder revolution, the revolution marker is only produced once in the cam. If, however, there are several incremental revolutions in the cam, the last active edge of the revolution marker signal triggers the preset.
Preset on long cam reference point
The time diagrams below show preset mode on a reference point long cam.
NOTE: preset is taken into account on the first rising edge of the IZ revolution marker input, which follows the change of Ipres input to status 0, both in the counting and the down counting directions and software enabling.
