ID
Index Name
Unit Description
507
0
ENC_CH3_Sel = 3
Encoder selection set to TTL(3)
514
0
ENC_CH3_Num
Encoder gearing: Numerator
515
0
ENC_CH3_Denom
Encoder gearing: Denominator
570
0
ENC_CH3_Abs
Selection of absolute value interface
571
0
ENC_CH3_NpTest
ENC CH1, TEST-MODE: Index pulse signal(s) to Scope
572
0
ENC_CH3_Lines
Number of lines (Sin/Cos / TTL encoders)
2842
0
ENC_CH3_TTL_SignalType
Channel 3: TTL signal selection
602
0
ENC_CH3_Period
Maximum period of interpolation (ttl encoder)
636
0
ENC_CH3_CycleCount
Sampling cycle in: n x 125 μ (microseconds)
Table 6.23: Parameters for Channel 3 (X8) - TTL encoder
6.7.5.2 Sin/Cos encoder
Ch3: SINCOS(1) - Sin/Cos signals
Sin/Cos encoders can ...
a. Be pure incremental encoders
without
an absolute value interface. In this
case,
P 570[0] - ENC_CH3_Abs
must be set to OFF(0).
b. Be incremental encoders
▸
with
an absolute value interface. In this case,
P 570[0] - ENC_CH3_Abs
must be accordingly set to SSI(1) or EnDat(2) so
that it will be possible to read the absolute encoder position for the absolute
value initialization routine once during the initialization phase.
6.7.5.2.1 Purely Sin/Cos incremental encoders
To run these encoders as pure incremental encoders with a zero pulse on encoder
channel Ch3 (without an absolute value interface), the approach is basically the
same as for pure TTL operation (see Section "TTL encoder" on page 82). The same
parameters apply.
However, there are the following differences:
MOOG
ID No.: CB40859-001 Date: 11/2020
MSD Servo Drive - Device Help
84
6 Encoder
a. There are no different signal types for the Sin/Cos signal (always 1 Vss for
cosine and sine).
b. The zero pulse is the analog zero pulse typical of Sin/Cos encoders (see the
“Connection for high-resolution encoders” section in the operation manual
MSD Servo Drive Single-Axis System, for example).
6.7.5.2.2 Linear Sin/Cos incremental encoders
Linear Sin/Cos encoders are operated as rotary encoders. For linear motor
operation, P 572[0] - ENC_CH3_Lines and the encoder gearing (see Section
"Encoder gearing" on page 89) are used to establish the ratio for the linear motor’s
pole pair subdivision (North-North) for commutation. 1 x North-North corresponds to
one revolution from Lines. In this case, the motor pole pair number must be set to 1.
P 582[0] - ENC_CH3_PeriodLen is not used in this case.
6.7.5.2.3 Signal correction (GPOC)
The GPOC (gain phase offset correction) routine used for track signal correction
purposes for sine/cosine signals is used to compensate for systematic errors. The
routine is controlled in encoder channel Ch3 with P 586[0] - ENC_CH3_Corr and
P 587[0] - ENC_CH3_CorrVal. For details see Section "Signal correction GPOC
(Gain Phase Offset Correction)" on page 74.
6.7.5.2.4 Sin/Cos incremental encoders with absolute value
interface
The following table lists the parameters for cyclical Sin/Cos operation on encoder
channel Ch 3 with one-time reading of the absolute encoder position via the
absolute value interface, i.e. without a zero pulse:
