Delta ASDA-A2 Series User Manual page 698

Chapter 12 Absolute System
The step explanation for the communication:
①
At the very beginning of communication, the host controller must enable ABSE and
all the communication starts from here.
②
A threshold time Ts for confirming the signal ABSE is necessary. After the signal has
been recognized, the DI4, DO2, and DO3 (no matter what their functions are), will be
switched to the function of ABSQ, ABSR, and ABSD respectively. At the moment of the
communication function enabled, if the signal of ABSQ is in high level, it will keep
high level for its original function and also will be high level signal for ABSQ. DI4,
DO2, and DO3 are multiple functions pins, please be noted especially at the moment
of communication function switching on and off. For the purpose of simplifying the
application, the functions of these three digital inputs and outputs could to set to 0
for communication use only.
③
When ABSE is at high level and retaining Ts long, the function of DI4 will be switched
to ABSQ. If the host controller switch ABSQ to low after it is defined, the servo drive
will recognize that host controller wants to read data from it.
④
After confirming time
ABSD and the signal ABSR is enabled for signaling the host controller to get data
from the servo drive side. If the longest possible waiting time of
expired, the host controller still cannot get the signal ABSR from low to high which
could be a problem of wiring disconnection.
⑤
After the host controller detects that ABSR is high, the data is fetched. The ABSQ will
be set to signal high to inform the drive after dada read.
⑥
After confirming time
low for signaling the host controller to be ready for accessing next bit.
⑦
The host will set ABSQ to low when it detects that ABSR is low for requesting the next
bit from drive.
⑧
The servo drive will repeat the steps 3 to 4 to put its data at ABSD for next bit
communication
⑨
By repeating steps 5 t o 7, the host controller will get the data, bit, and have an
acknowledgement to the servo drive.
⑩
The third bit data is ready on the servo drive side.
⑪
After the data is ready and has been held for time
see the signal ABSQ controlled by the host controller, and then the servo drive will
have a communication error flag ABSW raise to terminate the communication
procedure.
⑫
The host controller will set the ABSE to low for restart the communication cycle after
getting the communication error message from the servo drive.
Revision September 2012
T
, the data for communication is already well prepared on
Q
T
for ABSQ kept high, the servo drive will maintain ABSR to
N
T
(see Figure 12.4)
Q
T
, the servo drive still does not
R
A2
ASDA-
12-21