Festo SFC-DC series, Manual

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B. Supplementary information
B−47
Festo P.BE−SFC−DC−IO−EN en 0801a
B.6 Converting the measuring units
A measuring system must be defined for specifying the para
meters of the electric axis. In order to enable simple parame
trizing for different application cases, the controller can be
set via the control panel or FCT so that the user can specify or
read all variables directly in the desired units on the drive,
e.g.:
Metric measuring system for linear movements
(mm, mm/s, mm/s
2
)
Imperial measuring system (inch, inch/s, inch/s
2
)
Each physical variable (position, speed and acceleration) is
adapted to the relevant measuring system by means of a
conversion factor.
In the controller all parameters are always saved in increment
specifications (inc, inc/s, inc/s
2
) and not converted until they
are written or read. For the display, conversion from the inter
nal basis system into the (pre)set measuring system takes
place within the firmware; for representation on the PC moni
tor within the FCT software. In this way, the user does not
need to carry out conversion when entering values or when
reading on the control panel or in the FCT.
The direct transfer of values via the serial interface with CI
commands always takes place in the basis system and it is
assumed that conversion into increments has already taken
place.
Conversion is carried out via the parameters:
feed constant, depending on the drive
gear reduction
encoder resolution = physical measuring step per motor
revolution. For the SFC−DC: pulse quadruplication by digi
tal interpolation.