position / speed mode - Harmonic Drive LLC

Chapter 2Functions
Note 1: Both output signals of phase-A and phase-B are settled at LOW-level. To settle at LOW-level, at
least three pulses are outputted. Make a sequence for the host device ignoring outputted pulses while the
phase-Z is LOW-level before generating an absolute pulse train, and during other LOW-level duration of
the phase-Z signal.
Note 2: An absolute pulse train for single-turn encoder is outputted after around 1 ms of outputting
phase-Z signal.
Note 3: The servo-ON signal is unaccepted until completing the transmission of a set of absolute pulse
trains by the [absolute data request] signal.
Note 4: The [alarm 57] occurs if the single-turn encoder rotates more than 127 resolvable position while
the multi-turn counter is transmitting an absolute pulse train.
Acquiring multi-turn count
For FWD revolution of the encoder (motor), the phase-A signal has 90 degree phase shift against
phase-B signal, and for REV revolution the phase-A signal has 90 degree phase delay against phase-B
signal as shown below.
Increasing or decreasing the multi-turn counter of the host device should be discriminated by the phase
shift or delay of phase-A against phase-B. Acquire the signal at rising edge of the signal.
FWD revolution
REV revolution
Phase-A
Phase-B
Count
0 +1 +2 +3 0 123
Acquiring single-turn encoder and incremental pulse trains
For FWD revolution of the encoder (motor), the phase-A signal has 90 degree phase shift against
phase-B signal, and for REV revolution the phase-A signal has 90 degree phase delay against phase-B
signal as shown below.
Increasing or decreasing the single-turn encoder counter of the host device should be discriminated by
the phase shift or delay of phase-A against phase-B. Acquire the signal at rising and falling edge of the
signal.
FWD revolution
REV revolution
Phase-A
Phase-B
Count 0 +1
z
+2
z
+3
z
+4
z
0 -1 -2 -3 -4
- 19 -