Other parameters, such as Num and Denom, are described elsewhere (see
Section "X6 encoder gearing" on page 73).
P 561[0] - ENC_CH2_Corr
= Signal correction type
The GPOC routine used for track signal correction purposes for sine/cosine
signals is used to compensate for systematic errors. The routine is controlled
with the
Corr
and
CorrVal
parameters (
see Section
"Signal correction
GPOC
(Gain Phase Offset Correction)" on page 71).
P 563[0] - ENC_CH2_EncObsMin
= Encoder monitoring minimum, sqrt
(a²
+b²)
This parameter is used to scale the resolver and Sin/Cos wire break
monitoring and
represents
the “
downwards threshold
” for an error
message.
The default setting is 0.2, corresponding to approx. 20 % of the
track signals’
amplitude (approx. 80 % corresponds to approx. 1 Vss). If
EncObsMin
is set
to 0,
the
resolver and Sin/Cos wire break monitoring will be
disabled (
see
Section
"Channel 1: Interface X7" on page 56
as well).
MOOG
ID
No.:
CB40859-001
Date:
02/2018
MSD Servo Drive - Device Help
71
6 Encoder
When using long resolver cables, there will be a phase difference between the drive
exciter output signal and the drive track input signals (S1-S3 and S2-S4). This phase
difference can be compensated for with P 565[0] - ResExc: ResExc is the time, in µs
(microseconds), by which the resolver excitation will lead. Moreover, P 565[1] - Delay
can be used to compensate for a commutation dead time, which can become
important in the case of higher rotating field frequencies. When there is an absolute
reduction in signal strengths (amplitudes) as a result of the long cables, P 566[0] -
ENC_CH2_Amplitude can be used to subsequently increase these amplitudes (up to
a maximum of +10.5 %) so that there will be a magnitude level of 80–85 % for track
signals. This is achieved by adjusting the resolver excitation amplitude. Parameter
P 567[0] - ENC_CH2_EncObsAct can be used to check the effects of adjusting the
compensation settings. It returns the length of the phasor for track signals (sqrt(a²+b²))
and is accordingly a measure of “the amplitude” of track signals: If the phase shift is
properly corrected at the end of the compensation adjustment process, you can save
the settings.
NOTE
This function is not available for the MSD Single-Axis Servo Drive
Compact.
Do not use cable lengths > 50 m without first consulting with
Moog.
6.6.2 Signal correction GPOC (Gain Phase Offset
Cor
rection)
The resolver and Sin/Cos incremental encoder demonstrate systematic errors that
are reflected in the measured position and in the speed calculated from this (gain and
phase errors, offset components of the tracking signal). The GPOC method for track
signal correction compensates systematic errors. GPOC is available for encoder
channels 1 and 2.
6.6.1 Compensation for long resolver cables
P No.
Index
Unit Description
Name / Settings
µs
Correction of phase shift for cable lengths
> 50 m (only after consultation with
LTI Motion).
0
ResExc
us
Exciter signal phase shift
Delay
us
Compensation for commutation angle
delay
566
Correction of amplitude for cable lengths >
50 m (only after consultation with
LTI Motion ).
567
0
ENC_CH2_EncObsAct
Amplitude of analogue signal
Table 6.16: Encoder configuration channel 2 (X6) parameters (continue)
The Sel and Lines parameters are self-explanatory.
