In general, the position with ec36 should be set at a defined position for linear en-
coders in order to prevent overflow or underflow. Otherwise jumps in position and
speed may occur or error ec01 = 91: "position difference too high" is triggered.
If the connected linear encoder shall be used only for a higher-level position control
or as a position display for a control, the corresponding encoder type must be set
in ec16 for EnDat or Hiperface for this purpose. As for rotary encoders, the en-
coder evaluation reads all required values from the electronic nameplate of the en-
coder.
For incremental encoders, the increments per revolution or the basic distance must
be set in ec29.
For BiSS and SSI, the entire digital resolution must be set in ec40. i.e. ec41 re-
mains 0.
However, if a linear motor shall be operated with current and speed control, special
settings are required, which are described below.
The control on the control board does not differentiate between rotary and linear
drives.
I.e. a linear motor must be "simulated" in such a way that a suitable rotary drive re-
sults for it. For this, parameters ec50 virtual round for linear encoder, dr06 rated
frequency and dr04 rated speed are set.
To do this, a piece of a certain length is mentally cut out of the linear drive, bent
into a circle and the two ends joined together to form a virtual, rotary drive.
The length of this piece must have be an integer number of position information (or
sine periods) AND an integer number of motor pole pairs. Otherwise, there would
be either a discontinuity (jump) in the position or an asymmetry in the motor struc-
ture at the point where the two ends are mentally joined together.
6.1.7.1 dr06 rated frequency and dr04 rated speed
This adapts the motor to the imaginary (virtual) rotatory drive.
6.1.7.2 ec50 virtual round for linear encoder and the difference to ec29
This adapts the encoder to the imaginary (virtual) rotary drive.
In parameter ec50, which is only necessary for linear encoders, it is entered how
much of the position information from the encoder covers a multiple number of mo-
tor pole pairs.
- ec50 determines how long the encoder has passed a virtual revolution. This also
defines the value of the position parameters, e.g. ru33 for one revolution or the re-
sult of the speed in ru09.
ec50 is dependent on the used motor.
- As before ec29 is iincrements per revolution. Just as for rotary encoders, the
number of signal periods between the zero signals (or also reference marks) is set
here. In the case of distance-coded reference marks, the base distance is set here.
(More about the reference signals, see 6.1.8 „Operation of non-absolute linear en-
coders (with and without reference marks)“, page 254)
ec29 is dependent on the used encoder.
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