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PARVEX Motion Explorer Software - DIGIVEX Motion Module
Let's take as an example a 360° rotary plate. If the user selects a lower limit of -180° and an upper
limit of +180°, the axis position will always be between -180° and +180° whatever the cumulative
movements made by the axis. The position set-points and the measured positions will be taken to
be "modulo 360°". (The modulo corresponds to the difference upper limit - lower limit.) "Apply the
specified modulo" means the user does not need to control the equivalence relation between the
absolute positions -180° and +180°. Applying a modulo with an upper limit of +180° and a lower
limit of -180° to the value of 470° returns 110° (470° - n times the modulo, where n = 1); applying it
to a value of -200° returns +160° (-200° + n times the modulo, where n = 1). When a movement is
requested, motion is not controlled with the notion of the "shortest path". A request for movement
to the absolute position 900° will make the plate turn through 2 1/2 revolutions. When motion is
completed, the position counter will show +180° (900° - n times the modulo, where n = 2).
The modulo function also makes it possible to avoid reaching the maximum counting capacity of
the system. Unless otherwise specified by the user, the system will apply of its own accord and as
a safety measure a modulo with an upper limit of 10000000 unit1 (or 100000000 encoder
transitions) and for the lower limit a lower limit value of -10000000 unit1 (or -1000000000 encoder
transitions).
Tip: the modulo upper limit and modulo lower limit values must correspond to a complete number
of encoder increments or encoder emulation increments so as to avoid losing remainders from
division operations.
Apply
modulo
specified Check D this box to validate the modulo specified by the upper limit and
lower limit fields below.
[corresponding parameter: modul1_en]
If this box is not checked, the system modulo will be applied.
Modulo upper limit Enter the value of the upper threshold of the modulo in this field.
[corresponding parameter: modul1_up]
Modulo lower limit
Enter the value of the lower threshold of the modulo in this field.
[corresponding parameter: modul1_low]
5.2.1.5 Movement
In this field, enter the selected acceleration / deceleration level, expressed in
unit1/s2. See the Setting Calculation tab in the Servocontrol Settings window
for information on programming values.
[Corresponding Parameter: accel_max]
In this field, enter the stop window value desired in unit1. This value is used
Stop Window
to declare the end of a movement (axis stationary).
[Corresponding Parameter: target]
In this field, enter the maximum speed of the application expressed in unit1/s.
Max. Speed for
See the Setting Calculation tab in the Servocontrol Settings window for
Application
information on programming values.
[Corresponding Parameter: speed_max]
Maximum Tracking In this field, enter the maximum tracking error authorized, expressed in unit1.
[Corresponding Parameter: trackerror_max]
Error
Acceleration /
Deceleration
30
PVD 3516 GB 04/2004