6.7.5.1.1 Pure TTL incremental encoder
Set P 507[0] - ENC_CH3_Sel to TTL(3) and P 570[0] - ENC_CH3_Abs to OFF(0)
when using pure TTL encoders, i.e. encoders without an absolute value interface but
with a TTL zero pulse.
Linear TTL encoders are run as rotary encoders. For linear motor operation, P 572
[0] - ENC_CH3_Lines and the encoder gearing (see the “Encoder gearing” section)
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.
The TTL interface accepts various TTL signal types, which can be selected using
P 2824[0] - ENC_CH3_TTL_SignalType:
l
(0) AF_B - A/B tracks (forward counting, X4 encoding) - AB
l
(1) AR_B - A/B tracks (reverse counting, X4 encoding) - AB_inv
l
(2) ABDFN - A: Clock (falling edge), B: Direction (1 = positive) - PulseDir
l
(3) ABDRP - A: Clock (rising edge), B: Direction (1 = negative) - PulseDir_inv
l
(4) reserved
MOOG
ID No.: CB40859-001 Date: 11/2020
MSD Servo Drive - Device Help
83
6 Encoder
A maximum interpolation period, in ms (milliseconds), can be configured for the TTL
interface using
P 602[0] - ENC_CH3_Period
. Within this context,
Period
is the
maximum time of “no activity” since the last TTL counter event:
l
Period = 0: Function disabled (default)
l
Period > 0 (=n ms): If no counter event is registered in n ms, the speed will be
set to 0.
Zero pulse
There is no parameter for activating the zero pulse evaluation here, as this
evaluation is controlled based exclusively on the homing mode (see Section
"Homing" on page 249). However, setting P 571[0] - ENC_CH3_NpTest to 1
provides a test mode that can be used during commissioning in order to be able to
activate the zero pulse evaluation even without homing. Scope signals 1034 and
1036 can be used to view a received zero pulse within this context. This test mode
must be disabled during normal operation (P 571[0] = 0).
Commutation
Motor operation with pure incremental encoders needs for the auto commutation
function to be enabled without fail. For details see Section "Synchronous motor auto
6.7.5.1.2 TTL incremental encoder with SSI absolute
value interface
see Section "Sin/Cos incremental encoders with absolute value interface" on page
84 and in specialSection "SSI absolute value interface" on page 86.
