Bosch Rexroth OptiFeed-FS EcoDrive 03 FLP04VRS, Functional Description

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8-56
Functions ECODRIVE03-FL*-04VRS
DOK-ECODR3-FL*-04VRS**-FK01-EN-P
Incremental encoders do not have an automatic method of
determining an unambiguous position after powering up and must be
homed. Homing uses the incremental encoder emulator zero pulse.
With incremental encoders (e.g., sine encoders, gearwheel encoders),
the following occurs automatically each time manual or automatic mode is
engaged (in other words, each time the drive controller is powered up):
•
Detection of the motor encoder internal reference point is activated.
•
The zero pulse output of the incremental encoder emulator is blocked.
•
The increment output is activated.
As soon as the motor encoder internal reference point is detected, the
following takes place:
•
general release of the zero pulse output
•
immediate output of a zero pulse by the emulator
•
initialization of the zero pulse so that in the future it is always output at
this absolute motor position.
Note: Output of the zero pulse occurs after homing has been
successfully completed. It is then always output at the same
position (reference mark).
With rotary motors, it is possible to offset the zero pulse using C016,
Marker pulse offset within one (electrical or mechanical) rotation in a
clockwise direction.
The unit used in C016 is the degree. For motor encoders which provide
an absolute, unambiguous position within one motor revolution after
their initialization, the input range is 0..359.9 degrees.
The input range for resolvers which provide an absolute, unambiguous
position within one electrical revolution is
359.9 degrees /number of pole pairs.
Limits on Incremental Encoder Emulation
In contrast to the conventional incremental encoder in which the pulse
output frequency is virtually infinitely adjustable in very fine increments
(i.e., the pulse edges are always assigned to fixed positions), emulated
incremental encoder signals are subject to certain restrictions. These
restrictions are primarily the result of how the digital process of the drive
controller works.
The maximum pulse frequency is 1024 kHz. If this frequency is exceeded,
pulses can be lost. The non-fatal error F253 Incremental encoder
emulator: Pulse frequency too high is generated. The emulated
position is then offset with respect to the real position.
I
f
n
max
max
max
=
∗
60
I
max
: maximum number of graduation marks
n
max
: allowable maximum speed in rpm
Fig. 8-32: Computing the maximum number of graduation marks
Incremental Encoder
Homing
Zero Pulse Offset
Maximum Output Frequency