treated as rotary SSI encoders (in this case, it is impossible to determine that
the system is a linear encoder system based on the encoder head). Likewise,
linear SinCos encoders without an absolute value interface are treated as
“rotary” encoders (if run as commutation encoders, the number of tracks, or
lines (
Lines
) and the encoder gearing (
Num, Denom
) must be used to
establish the relationship to the linear motor’s magn. pole pair subdivision).
Only in the case of SinCos encoders with distance-coded reference marks
will the system determine, based on
PeriodLen
> 0, that the encoder system
is linear and not rotary.
l
P 580[0] - ENC_CH3_Info
= Encoder Information
This parameter is available to the user so that they can enter a text of their
choice (max. 31 characters). This text should be used to describe the
encoder on channel Ch3
l
P 636[0] - ENC_CH3_CycleCount
= Sampling cycle in: n x 125 µs
(microseconds):
The CycleCount parameter can be used to slow down the timing for the
cyclical SSI encoder evaluation. By default, CycleCount = 1, i.e. the default
setting corresponds to 125 µs sampling and cycles for the encoder
evaluation. Different settings must be viewed as special cases and
accordingly must only be used when necessary. (see Section "SSI (cyclical)
X8" on page 89).
l
P 630[0] - ENC_CH3_NominalIncrementA
= distance coded absolute
encoder
P 631[0] - ENC_CH3_NominalIncrementB
= distance coded absolute
encoder
The NominalIncrementA and NominalIncrementB parameters make it
possible to run SinCos incremental encoders (without an absolute value
interface) with analogue distance-coded reference marks. E.g. If you were
using the Heidenhain ROD280C with 18000 SinCos tracks per revolution
and 36 distance-coded reference marks, you would need to set
NominalIncrementA to 1000 signal periods and NominalIncrementB to 1001
signal periods. This functionality is enabled if NominalIncrementA > 0. (see
Section "Increment-coded reference marks" on page 107).
l
P 637[0] - ENC_CH3_AbsInitMode
= Mode absolute value formation
AbsInitMode
can be used to select various possible settings for the absolute
ID No.: 0842.26B.5-01 Date: 09.2020
ServoOne - Device Help
88
6 Encoder
value initialization:
o
DIG_ANA(0)- Standard:
Absolute value initialization using a mix of the digital and analogue
components (this is the default mode)
o
DIG(1) - Digital:
Only the digital component will be used for the absolute value
initialization.
o
SEK_SEL37(2) - Automatic:
Digital if ST bits > (Li 8); otherwise standard
o
SSI_180(3) - Same as Standard, except:
In the case of SSI, the quadrant alignment of the digital value relative
to the analogue SinCos tracks is not the same as with EnDat, but is
instead offset by 180 degrees relative to EnDat, i.e. in the “natural Q
alignment” for the digital value relative to the tracks.
6.7.6.2.5 SSI absolute value interface
If P 570[0] - ENC_CH3_Abs = SSI(1), which is the normal setting, the absolute SSI
encoder position will be read once during the initialization phase; after this, the
cyclical encoder position will be acquired based on the SinCos incremental
component.
The parameters for the SSI interface are described in Section "SSI (cyclical) X8" on
page 89, as are the differences in using the SSI interface with the “cyclical” method
and “one-time reading” method.
6.7.6.2.6 EnDat absolute value interface
If P 570[0] - ENC_CH3_Abs = ENDAT(2), the absolute EnDat encoder position will
be read once during the initialization phase; after this, the cyclical encoder position
will be acquired based on the SinCos incremental component.