Delta ASD-A3-0121, User Manual

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ASDA-A3 Absolute System
Revision December, 2017
10-19
10
Descriptions:
(1) When handshake communication starts, the ABSE signal is triggered.
(2) After the T
S
delay time (make sure the signal is on), the functions for DI4, DO2, and DO3
are switched to ABSQ, ABSR, and ABSD, respectively. If DI4 was in the high-level state
before, it remains in the high-level state when switched to ABSQ (logic high-level signal).
DI4, DO2, and DO3 are dual-function DI/DO, which means DI4, DO2, and DO3 share the
same DI with ABSQ, ABSR, and ABSD. Please pay special attention when switching
functions or set the DI/DO to 0 to disable the dual-function of DI/DO.
(3) If DI4 is set to high and switched to ABSQ after the T
S
delay time, when the host controller
resets this signal to low, the new signal is interpreted as the data access command.
(4) After the T
Q
time, the handshake data is ready and the absolute position is sent to ABSD.
Now the servo drive turns on the ABSR signal, and the host controller can access the data.
If the host controller still cannot detect the ABSR status while it is changing to high after the
maximum T
Q
time (refer to Figure 10.3.6.1), there may be a communication error.
(5) Once the ABSR signal is set high, the host controller accesses the data, and the ABSQ
signal is set high to notify the servo drive that data was read.
(6) When ABSQ is high, the ABSR signal is set low after the T
N
time in order to send the data
for the next bit.
(7) When ABSR is low, ABSQ is also set low and the servo drive needs to send the data for the
next bit.
(8) Repeat step (3) – (4). Send the absolute position to ABSD for the next bit communication.
(9) Repeat step (5) – (7). The host controller has read and received the data.
(10) The third bit data is ready.
(11) After the T
R
waiting time, if the host controller has not read the data and turned on the
ABSQ signal, the servo drive sends the ABSW signal (communication error) and stops the
handshake communication.
(12) When the host controller receives the communication error signal, ABSE is set low and
prepares to re-start the handshake communication.
(13) ABSW resumes at low after the servo drive receives the ABSE signal.
(14) The host controller resumes communication after T
B
time.
(15) Repeat step (1).
(16) If no error occurs, the host controller completes 80 bits (0 – 79) of the handshake
communication with the servo drive.DI4, DO2, and DO3 then resume their original
functions.
Note: if ABSE is set low first and then changed to high, but ABSW does not return to high, it means some
other errors exist. Please check for the following possible warnings: absolute position lost, low battery
voltage level, or absolute position overflows. Restart a new communication cycle after those errors have
been cleared.