Parker Hannifin S.p.A. - Divisione S.B.C. “SPD” User’s Manual
54
8.6 Electronic cam (operating mode 14)
Operating mode 14 was expressly designed to meet the needs of packaging machines that
require electronic cams. The table of the cam function is described with a vector composed of
257 elements, each of which indicates the position that must be assumed by the controlled
axis when the master axis is in the position (element_number * master_module) / 256. The
value of the elements of the vector falls within the range 0 – 9999, where 10000 corresponds
to the number of counts set in the slave module parameter. The 257th element defines the cam
as closed if it = 0, or as open if it = 10000.
The mode selector can be used to select the source for the position loop the possible sources
are: no source, positioning, electronic cam and speed.
POSITIONING. The parameters that regulate movement are: target_pos, acc, speed.
Target_pos indicates the absolute position that is to be achieved; if it is included in the
movement direction module, it is given by the sign of the difference between target_pos and
Pr60:61. Acc is the maximum acceleration allowed during the movement and speed is the
maximum speed. The path generator will begin its work when the mode selector is set to 1,
When the position has been achieved, the mode selector automatically returns to.
Alternatively, the positioner module can be used to sum a phase on the master axis by setting
target_pos based on the actual offset phase position Pr116:117. At the start the calculation of
the path will be such as to guarantee continuity with the actual speed of the motor.
MASTER RE-PHASING. By setting the function (b150.8) the user can define the position of
the master (Pr122:123) on the positive side of digital input 0 or of the zero trace encoder input
(selector b70.0). b70.14 means that re-phasing was successful, and the user must set this flag
to. For this function b42.0=0 (see chapter Input/output connection in frequency).
CAM ENGAGING. A master phase can be defined to which the selector will automatically be
set to position 2 by enabling the cam module. A similar procedure can be used for release, In
this case, when the release phase has been programmed, the positioner will be enabled to
reach the desired position. The functioning of operating mode 14 is described in detail in the
block diagram.
Coupling is also possible in phase with the linear ramp, using command b150.11. In this case,
the master direction must be positive; setting b150.11=1 when the master Position reaches the
value of Pr132:133 the slave starts to move following a linear ramp so as to cover the space
defined by Pr136:137 when the master reaches point Pr126:127. In this point, the value of
Pr134:135 must be equal to the Position reached by the slave at the end of the ramp, or at the
beginning of the ramp the slave must be in advance relative to the phase coupling point, by a
distance equal to Pr136:137. The bit B150.11 is reset at the beginning of the ramp setting
b150.12=1. The continuity between the speeds (ramp and cam) is to be managed by the user.
Three functions are pre-defined that can be used to set the cam profile. By setting Pr102 = 5,
the function is y = x, Pr102=6 the function is y = x-sinx, Pr102=7 the function is y = sinx
where y is rated to 10000 on the 256 points of the cam. The compilation of the cam table is
done in the background and at the conclusion Pr102 is set to 0. Make sure that if b40.2=0, the
parameter Pr102 is nevertheless forced to 0.
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