Operating Principle - Siemens SIMOVERT MASTERDRIVE SLE Operating Instructions Manual

SLE / SLE-DP – SIMOLINK Encoder
6.3.4

Operating principle

NOTICE
CAUTION
Siemens AG GWE-477 763 4070.76 J
SIMOVERT MASTERDRIVES
02.2001
A position setpoint that is identical to the master setpoint transferred to
the main drives except for its normalization is sent to the SIMOLINK
Encoder in the 1.6 or 3.2 ms cycle in the setpoint telegram. Since the
position of the zero pulse (zero position) of the encoder need not match
the zero position of the master setpoint, it is possible to supply the
encoder with an offset by transmitting the reference position of the zero
pulse when pulse output is enabled (the offset cannot be altered once
the encoder is operating).
The SIMOLINK Encoder has two internal counters, one actual-value
counter and one setpoint counter. The actual-value counter is set to the
transferred 'setting value for zero pulse' by the 'SLE control' bit when
pulse output is enabled. This device counts the pulses output to the
encoder interface, and also outputs the zero pulse when it overruns
from 32767 to 0. The transferred 'momentary' setpoint is stored in the
setpoint counter. The difference between the contents of these two
counters constitutes the manipulated variable (number of pulses to be
output) for the frequency generator during the next cycle. The counters
always operate in a numerical range of 0 to 32767 owing to the pulse
quadruplication at 8192 pulses/rev needed to ensure a correct pulse
sequence and the 90° zero pulse. The electrical pulses output on the
encoder interface are acquired by frequency division depending on the
selected number of pulses per revolution.
The maximum speed of the SIMOLINK Encoder is 25 revolutions per
second (rated output frequency 204.800 kHz for 8192 pulses/rev.); it is
capable of outputting speeds of up to 125 % (max. output frequency
256.000 kHz) correctly.
The SIMOLINK Encoder achieves the same dynamic response as
MASTERDRIVES MC devices by delaying transfer of the setpoint for a
period corresponding to the setpoint transit delay in the
MASTERDRIVES MC. This means in practice that a position-controlled
MC device reaches the same position as the SIMOLINK Encoder in
terms of actual position in every cycle (both devices with no offset or an
identical offset in relation to master axis). The configuring parameter
settings for the MC device must be noted in this respect (cf. Section
6.5).
If transmission errors occur on the SIMOLINK, then a transmission
cycle may be missed, i.e. the SYNC pulse is not transferred. If the SLE
has reached its interpolated setpoint before the error occurs, then it
stops. Since the SYNC pulse does not arrive, no pulses are output, and
the angular position thus left unchanged, until the next SYNC pulse
arrives.
Operating Instructions
Start-Up
6-11