User`s manual

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downloads the commands from the buffer by batches, it must know the remaining space in the buffer through the
query command “adt8840a_get_buff_depth（）”, so as to avoid the overflow of software cache. In this mode, only
when the current command is fully executed, can the next command be executed. When this mode is enabled, if
any hardware buffer commands are downloaded into the control card while the non-hardware buffer commands are
being executed, the hardware buffer commands will also be saved in the software buffer. Once all non-hardware
buffer commands are executed, the hardware buffer commands will be saved in the hardware buffer. Please note
that the hardware buffer commands accumulated in the software buffer should not exceed the capacity of the
hardware buffer.
The immediate execution mode refers to a machining method used when the buffer is closed. In this mode, the user
can only transmit the commands in the way the single command is executed. In other words, when the control card
is executing the motion commands, the user must judge at the upper PC whether the current motion is completed.
Only when the completion of motion is detected, can the next command be executed. Otherwise, the motion state
might become confused.
In addition to the software buffer mode, ADT-8840 also provides some interpolation functions with hardware
buffer, such as:
adt8840a_fifo_inp_move1(),
adt8840a_fifo_inp_move2(),
adt8840a_fifo_inp_move3(),
adt8840a_fifo_inp_move4(),
Details on interpolation of hardware buffer will be provided in the follow-up chapters of this Manual.
) Position management
 Logic-position counter and actual-position counter
The logic-position counter counts the number of pulses based on the positive/negative direction output. In other
words, it counts “1” upward when one positive pulse is output, and “1” downward when one negative pulse is
output.
The actual-position counter counts the pulses coming from the external encoder. The user can use the commands to
select the pulse type as phase A/B signal or independent 2 pulses of upward/downward counted signals. The
counting direction can be set.
The data of the two counters can be written and read at any time, whose counting ranges between
-2,147,483,648 ～ +2,147,483,647.