Lenze EVS93xx CrossCutter - Manual (Page 29)

Cross Cutter
Features of the "Cross Cutter" prepared solution
 Prepared Solution Servo PLC / ECSxA 1.1 EN 2-15
2.4 Machine parameters
The machine parameters define the relationship prevailing between the user's measuring
system and the incremental measuring system (the controller's internal measuring system).
Where the user's measuring system is concerned, a distinction is drawn between slave units
([s_units]) and master units ([m_units]). The cross-cutter drum's measuring system is provided
by the slave units. In this context, slave units are usually scaled in degrees. The feed axis'
measuring system is provided by the master units which, depending on the application, might
be scaled in [mm] or [inches]. The relationship between a motor revolution and a feed motion in
the user's measuring system is established by means of the following variables:
• Feed constant: This indicates the number of application units by which the load will move
forward when the drive completes a full revolution at the gearbox output end. It is usually
specified in [units/rev].
Example: On a spindle drive the feed constant is equivalent to the pitch of the spindle,
scaled in [mm/revolution].
• Gearbox ratio, divided into numerator and denominator: Both the numerator and the
denominator are usually specified as integers (corresponding to the number of teeth in the
gearbox stages).
• Resolution of a motor revolution: Internally, the ServoPLC resolves a motor revolution into
65536 (=2 16 ) increments.
The conversion between the two measuring systems can be carried out with knowledge of
these mechanical machine constants by applying the following formulae:
a) Conversion of application units [units] into incremental units [incr.]:
[ ] [ ]
[ ]
[ ]
rev units m
rev incr
N
Z
units s s incr s
t FeedCons i
i
/
/ . 65536
_ .
tan
⋅ ⋅ =
a) Conversion of incremental units [incr.] into application units [units]:
[ ] [ ]
[ ]
[ ]
rev incr
rev units m
Z
N
incr s units s s
t FeedCons
i
i
/ . 65536
/
. _
tan ⋅ ⋅ =
where Z
i
= gearbox ratio numerator
N
i
= gearbox ratio denominator
m
FeedConstant
= feed constant
In the context of the Cross Cutter prepared solution, the mechanical machine constants are
defined via profile data (LC9 file). A description of how this data is generated appears in the
installation and start-up instructions (see Chapter 3.4.2).