3
05.01
3.2 Motor encoder
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©
Siemens AG 2012 All Rights Reserved
SIMODRIVE 611 Configuration Manual (PJU) – 02/2012 Edition
Encoder sin/cos 1 Vpp
–
”High Performance” and SIMODRIVE 611 universal control units can be
parameterized for encoders up to 65,535 incr./rev. The increment value
is increased by the factor 2048 using pulse multiplication in the evalua-
tion of the modules.
Encoders with 2048 incr./rev. are used in preference. The resolution is
then approx. 4.2 million incr./rev. An increment then represents on a
10 mm spindle (10 mm/(2048
2048) = 2.4 nm.
–
This means the ”High Standard” control unit with a pulse multiplication of
128 with the standard encoder would then be resolved theoretically up to
(10 mm/2048/128) = 38 nm with the 10 mm spindle.
–
For direct measuring systems (internal pulse multiplication also 2048),
an encoder pulse number up to 32 bits can be set.
–
Linear scales can be parameterized with grid divisions from 0 to
8,388,607 nm. Linear encoders with 20
μ
m grid division are used primar-
ily; the resolution is then (20
μ
m/2048) = 10 nm.
–
The encoder limit frequency f
G
, with sin/cos 1 Vpp encoders, for ”High
Performance” and SIMODRIVE 611 universal control units can be as
high as 350 kHz, with secondary conditions up to 420 kHz, and max.
200 kHz for ”High Standard” control units.
–
With the encoder 2048 incr./rev., with 350 kHz
(60s/2048) up to
10,250 RPM can be processed.
–
The ”High Standard” control unit with the standard encoder permits max.
200 kHz
(60s/2048) up to 5,860 RPM.
–
Linear encoders (20
μ
m grid) permit speeds with
350 kHz
(20
μ
m
60s) up to 420 m/min.
Resolver
–
The SIMODRIVE 611 universal control unit in the variant with resolver
(1 – 6 pole pairs) permits resolutions with 12– or 14–bit and encoder limit
frequencies up to 432 Hz or 108 Hz.
–
For a resolver with 1 pole pair, 12– or 14–bit achieves the resolution
4,096/rev. or 16,384/rev. namely 4,096 incr./rev. or 16,384 incr./rev.
–
The position resolution with 10 mm spindle pitch corresponds theoreti-
cally to 2.5
μ
m or 0.6
μ
m. The values are correspondingly more favor-
able for resolvers with a higher number of poles, e.g. for six pole pairs.
–
Maximum speeds can be achieved with 12 bits and for pole pair 1 to
432
60 =
26,000 RPM and with 14 bits up to approx. 6,500 RPM.
Resolvers with a larger number of poles, e.g. six pole pairs, permit only
correspondingly lower speeds.
Note
Because encoder systems (as result of excitation frequency, excitation
amplitudes, windings, non–symmetry of the poles) can exhibit relatively high
tolerances in the evaluation for analog/digital conversion, the actually
achievable values are significantly lower in practice.
Theoretic
resolutions in
SIMODRIVE
modules
3 Motor Selection, Position/Speed Sensing
05.08
