8 Pulse Output Units
8 - 56
NX-series Position Interface Units User’s Manual (W524)
The position-synchronous pulse output method outputs all the pulses for the command position within
each control period. The velocity-continuous pulse output method outputs pulses to maintain the speci-
fied command velocity by specifying a command velocity that corresponds to the command position.
Therefore, the actual pulse output depends on the output method used.
Conceptual Description of Pulse Output
The following figure serves as an example. The pulse output will depend on the actual command
position and command velocity.
Precautions for Correct Use
For the velocity-continuous pulse output method, you must specify a command velocity to go
along with the command position that is given every control period. If you specify a command
velocity that is not compatible with the command position, this may result in sudden changes in
the pulse output, pulse output across more than one control period, or other unintended output.
Use the MC Function Module in an NJ/NX-series Controller to automatically calculate the com-
mand velocity when you use the velocity-continuous pulse output method.
Differences between Position-synchronous Pulse Output and Veloc-
ity-continuous Pulse Output
Letter Description
(a) The differential travel distance for the command position is output in the control period. The com-
mand velocity has no effect.
(b) Depending on the resolution of the velocity, the velocity may not be continuous.
(c) Pulses are output for the differential travel distance for the command position based on the velocity
command (3.5). The travel distance is 4.
(d) Pulses are output for the differential travel distance for the command position based on the velocity
command (5.5). The travel distance is 6.
(e) Pulses are output for the differential travel distance for the command position based on the velocity
command (7.5). The travel distance is 7.
(f) Pulses are output for the differential travel distance for the command position based on the velocity
command (5.5). The travel distance is 6.
(g) Pulses are output for the differential travel distance for the command position based on the velocity
command (3.5). The travel distance is 4.
4 1017232727
3.5 5.5 7.5 5.5 3.5 0
Time
Control period
Command position
Command velocity
Command values
from Controller
Outputting pulses with
position-synchronous
pulse output
Outputting pulses with
velocity-continuous
pulse output
(a)
(c) (d) (e) (f) (g)
(b)
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