User`s guide

Operation Theorem • 47
4.2 Motor Driver Interface
The PCI-8134 provides the INP, ERC and ALM signals for servomotor
driver’s control interface. The INP and ALM are used for feedback the
servo driver’s status. The ERC is used to reset the servo driver’s deviation
counter under special conditions.
4.2.1 INP
Usually, servomotor driver with pulse train input has a deviation (position
error) counter to detect the deviation between the input pulse command and
feedback counter. The driver controls the motion of servomotor to minimize
the deviation until it becomes 0. Theoretically, the servomotor operates
with some time delay from command pulses. Accordingly, when the pulse
generator stops outputting pulses, the servomotor does not stop but keep
running until the deviation counter become zero. At this mom ent, the servo
driver sends out the in-position signal (INP) to the pulse generator to
indicate the motor stops running.
Usually, the PCI-8134 stops outputting pulses upon completion of outputting
designated pulses. But by setting inp_enable parameter in set_inp_logic()
function, you can delay the completion of operation to the time when the
INP signal is turned on. Status of motion_done() and INT signal are also
delayed. That is, when performing under position control mode, the
completion of start_a_move(), start_r_move(), start_s_move() …
functions are delayed until INP signal is turned ON.
However, EL or ALM signal or the completion of home return does not
cause the INP signal to delay the timing of completion. The INP signal may
be a pulse signal, of which the shortest width is 5 micro seconds.
The in-position function can be enable or disable. The input logic polarity
isalso programmable by software function:set_inp_logic(). The signal
status can be monitored by software function: get_io_status().
4.2.2 ALM
The ALM pin receives the alarm signal output from the servo driver. The
signal immediately stops the PCI-8134 from generating pulses or stops it
after deceleration. If the ALM signal is in the ON status at the start, the PCI-
8134 outputs the INT signal without generating any command pulse. The
ALM signal may be a pulse signal, of which the shortest width is a time
length of 5 micro seconds.