ADLINK HSL-4XMO - Manual (Page 79)

Operation Theory 69
HSL_M_set_command() can be executed at any time to set a new
command position value. To read current command position use
HSL_M_get_command().
X
Relative Functions:
HSL_M_set_command(), HSL_M_get_command():
Feedback Position Counter
The HSL-4XMO has a 28-bit binary up/down counter managing
the present position feedback for each axis. The counter counts
signal inputs from the EA and EB pins.
It accepts 2 kinds of pulse inputs: (1). Plus and minus pulse inputs
(CW/CCW mode). (2). 90° phase shifted signals (AB phase
mode). 90° phase shifted signals maybe multiplied by a factor of 1,
2 or 4. 4x AB phase mode is the most commonly used in incre-
mental encoder inputs. For example, if a rotary encoder has 2000
pulses per phase (A or B phase), then the value read from the
counter will be 8000 pulses per turn or –8000 pulses per turn
depending on its rotating direction. These input modes can be
selected using the HSL_M_set_pls_iptmode() function.
In cases where the application has not implemented an encoder, it
is possible to set the feedback counter source to generate the out-
put pulses, just as with the command counter. Thus, the feedback
counter and the command counter will have the same value. To
enable the counters to count the number of pulses inputted, set
the “Src” parameter of the software function
HSL_M_set_feedback_src() to “1.”
Plus and Minus Pulses Input Mode (CW/CCW Mode)
The pattern of pulses in this mode is the same as the Dual Pulse
Output Mode in the Pulse Command Output section; except that
the input pins are EA and EB.
In this mode, pulses from EA cause the counter to count up,
whereas EB caused the counter to count down.
90° Phase Difference Signals Input Mode (AB phase Mode)
In this mode, the EA signal is a 90° phase leading or lagging in
comparison with the EB signal. “Lead” or “lag” of phase difference
between two signals is caused by the turning direction of the