8-8
Drive Functions
MPH-02, MPB-02, MPD-02
DOK-INDRV*-MP*-02VRS**-FK01-EN-P
sequence for establishing the position data reference are made via
assigned parameters.
The dedicated point for establishing the position data reference, in the
case of linear axes, is at one end of the travel range. This allows finding
the reference point from any axis position (situation when switched on) by
moving in a defined direction. Rotary axes do not have an axis end
position, the dedicated point is at a defined position within the travel
range.
The precision with which this dedicated point is detected considerably
influences the absolute precision of the axis. Apart from the signals for
position detection, relative measuring systems therefore also provide a
signal for exact determination of a dedicated point. This signal is called
"reference mark". Depending on their type, relative measuring systems
have one or several reference marks over the range of measurement.
Especially in the case of rotary measuring systems (e.g. motor encoder)
at axes moved in a linear way, the reference mark of the encoder can
occur several times over the entire travel range. In this case it is required,
by axis-side activation of a switch contact at the end of the travel range, to
particularly identify
one
reference mark signal. This defines an
unequivocal dedicated point that can be found with reproducible precision.
This switch contact is called "home switch".
Independent of the number of reference marks over the travel range the
home switch, in the case of linear axes, is indispensable for detecting the
axis end position!
If only one reference mark occurs over the travel range in the case of
rotary axes, the home switch in most cases is not required!
The dedicated point identified by an encoder reference mark and, if
necessary, by a home switch, in most cases is not identical with the
reference point of the axis. The distance between reference point and
zero point normally is determined on the machine side. Especially in the
case of serial machines, this distance should be equal for axes of the
same kind. The position of the dedicated point, however, is influenced by
the kind of encoder arrangement and therefore differs from axis to axis.
The position difference between dedicated point and reference point of
the axis can be compensated by an offset value (reference offset).
See also "General Information on Establishing the Position Data
Reference" in this chapter"
Parameters for relative measuring systems:
•
S-0-0041, Homing velocity
•
S-0-0042, Homing acceleration
•
S-0-0052, Reference distance 1
•
S-0-0054, Reference distance 2
•
S-0-0108, Feedrate override
•
S-0-0147, Homing parameter
•
S-0-0148, C0600 Drive-controlled homing procedure command
•
S-0-0150, Reference offset 1
•
S-0-0151, Reference offset 2
•
S-0-0298, Reference cam shift
•
S-0-0299, Home switch offset
•
S-0-0349, Jerk limit bipolar
•
S-0-0400, Home switch
•
P-0-0153, Optimum distance home switch - reference mark
Dedicated Point for Establishing
the Position Data Reference
Reference Mark for Relative
Measuring Systems
Reference Mark and
Home Switch
Dedicated Point and Reference
Point of an Axis
Reference Offset
Pertinent Parameters
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