NPM PPCI7443, User Manual

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Operation Theorem
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75
4.4 The Counters
The PPCI7443 provides 4 counters for every axis, and, they are introduced
in this section:
Command position counter: To count the number of pulses output
Feedback position counter: To count the number of pulse input
Position error counter: To count the error between command and
feedback pulse number.
General-Purposed counter: The source could be configured as pulse
output, feedback pulse, manual pulser or CLK/2.
Also, the target position recorder, a software-maintained position recorder,
is discussed.
4.4.1 Command position counter
The command position counter is a 28-bits binary up/down counter, and its
input source is the output pulse from PPCI7443, thus, it provide as exact
information of current command position. Note: the command position is
different from target position. The command position increases or
decreases as pulse output, while the target position changes only when a
new motion command was executed. The target position is recorded by
software, and need manually resetting after home move completed.
The command position counter will be clear to “0” automatically after home
move completed. Besides, the function call, _
7443_set_command(), can
be executed in any time to set an new command position value. To read
current command position: _
7443_get_command().
Relative Functions:
_7443_set_command(),_7443_get_command(): Refer to section 6.15
4.4.2 Feedback position counter
The PPCI7443 has a 28-bits binary up/down counter for managing the
present position feedback for each axis. The counter counts signals input
from EA and EB pins.
It can accept 2 kinds of pulse input: (1). plus and minus pulses
input(CW/CCW mode); (2). 90
r
phase difference signals(AB phase mode).
90
r
phase difference signals may be selected to be multiplied by a factor of