Manual – IPOSplus®
73
6
Modulo function
Position Detection and Positioning
6.7 Modulo function
6.7.1 Introduction
The modulo function can be activated for endless unidirectional rotary applications such
as, for example, rotary tables or transport chains. This ensures that all position data in
the range 0 to (modulo value – 1 incr.) is displayed. When the modulo value defined by
the user (for example, 100 mm or 360°) is exceeded, the modulo position value is reset
to zero.
It is also possible to use the incremental value of the encoder selected in P941 for posi-
tioning and only to activate the modulo function in the background, for example, for
counting the revolutions of the output.
The modulo function has the following features:
• Position specification in output units. This can be used to specify a 360° turntable
rotation directly without having to convert it into IPOS
plus®
encoder increments as in
the past. For example:
– Turntable rotation 360° = modulo value = 2
16
increments.
– Distance to be covered in one machine cycle = modulo value = 2
16
increments
(rotary table with 4 stations: 1 cycle = 90° = modulo value).
• Permanently accurate positioning without long-term drift or positioning errors, even
for non-integer gear unit reduction ratios, as long as the project planning guidelines
are adhered to.
• Previous solutions involved mounting an external synchronous encoder or using a
digital input to register the zero cross-over, which meant additional programming in
IPOS
plus®
.
• Absolute position specification over several revolutions.
• Specification of a travel strategy: The position setpoint can be reached either via the
shortest route, or from CW or CCW.
Endless positioning in combination with absolute encoder evaluation via DIP11 is
available as of firmware version 14 (822 890 6.14) (fault F92 DIP work area no longer
occurs when the modulo function is activated).
INFORMATION
Depending on the system, the gear unit and, if necessary, any additional gears must
be simulated via the number of teeth. Ask the manufacturer of your gear unit for the
exact number of teeth. Do not accept the ratio from the nameplate. Furthermore, the
maximum target position that can be represented is determined when the gear unit is
selected. This value must not be exceeded. This must be taken into account in the
project planning phase (see the Project Planning section).
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