Synchronous Axis (To_Synchronousaxis); Cam Disc (To_Cam) - Siemens SIMATIC S7-1500 Manual
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Also See for SIMATIC S7-1500:
- System manual (523 pages) ,
- Function manual (402 pages) ,
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8 Example Application
8.2 Technology objects used
Saving the conveyor belt position in which the product is located:
The position of the conveyor belt detected via the measuring input technology
object represents the belt position at which the product has reached the light
barrier. The distance of the product to the light barrier can be specified in the
following at any point in time whilst taking into account the current position of
the conveyor belt.
Position correction of the conveyor belt:
The current position of the conveyor belt is corrected "on the fly" and thus
highly precisely, to a defined position with the help of the measured value
detected. Thus, the current position of the conveyor belt represents the current
position of the tool and can therefore be directly used by the other production
process of the plant.
In example application introduced here the first method is used.
Note
The evaluation of the two edges of the light barrier signal as well as the product
length can also be individually recorded and provided to the other production
steps via the measuring input. However, for reasons of clarity of the example
application this data acquisition is not used.
8.2.3
Synchronous axis (TO_SynchronousAxis)
A synchronous relationship to another axis technology object or external encoder
can be created via the synchronous axis technology object. The synchronous axis
presents the slave axis of the synchronous relationship.
In the example application introduced here, the synchronous axis drives the
sealing unit that is moved to the positioning axis via a non-linear synchronous
relationship. The synchronous axis was configured as modulo axis. The start
position of the sealing unit is located on the top dead center of the left drive role, so
that half the role's circumference in the cam disc can be used to adjust the speed
of the sealing unit to the speed of the belt.
8.2.4
Cam disc (TO_Cam)
A non-linear absolute connection for the movement of two axis can be defined via
the cam disc technology object. The cam disc represents the mathematical
synchronous relationship between a master and a slave axis.
In the example application presented here, the positioning axis technology object
of the conveyor belt is the master axis for the synchronous relationship with the
help of the cam disc. The synchronous axis technology object is used for the slave
axis. The slave axis drives the sealing unit. In parts, the sealing unit is moved
synchronously to the conveyor belt via the non-linear synchronous relationship.
The cam disc used in the example application is displayed in the following figure
and is made up of five cam disc segments. The individual segments of the cam
disc are defined via the type of the cam disc element and the coordinates of the
start and end point of the element in the coordinate system of the cam disc. The
value x always presents the conductance position, i.e. the position of the master
axis in the coordinate system of the cam disc, whilst f(x) defines the appropriate
position of the slave axis.
TOs of S7-1500(T)
Entry ID: 109743134,
V1.0,
05/2017
33
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