Delta ASD-A2 Series User Manual page 670

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 T
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 T
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 T
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 T
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.
⑬ . The communication error flag on servo drive side will be reset after detecting a low signal
ABSE from the host controller.
⑭ . A new communication cycle on host controller will be restarted after the buffering time T
⑮ . Repeat the step 1 for the host controller to start a new communication cycle.
Revision February, 2017
, the data for communication is already well prepared on ABSD and
Q
Q
for ABSQ kept high, the servo drive will maintain ABSR to low for
N
(see Figure 12.4) expired, the host controller still
, the servo drive still does not see the
R
ASDA-A2
.
B
12-21