6.5
EDH0162En1040 – 06/99
MM4005
Feature Descriptions Tutorial
6.1.2
Pulses Synchronized to a Trajectory
Equally spaced pulses can also be generated synchronous with a trajectory
(at pin 12 of the 25-pin D-Sub Auxiliary connector). The NB, NE, NI, NN and
NS commands are used as follows:
NB
nn
Defining and reading the trajectory element number where the
signal should start. The pulses are generated immediately when
this element starts executing.
NE
nn
Defining and reading the trajectory element number where the
signal should stop. The pulses will stop immediately when this
element finishes executing.
NI
nn
Defining and reading the distance (the step) on the trajectory
between synchronizing pulses.
NN
nn
Defining and reading the number of pulses (number of steps + 1)
that are generated in a symetric geometric fashion.
NS
Start generating the signal.
The NB, NE, NI and NN commands provide the necessary data to define the
signal generation while the NS command enables it. The correct location
for the NS command is right before the ET command. The pulses are termi-
nated at the location specified by the NE command or at the end of the tra-
jectory where the NS command’s effect ends automatically.
The necessary conditions (verified by ET) to generate the signal are:
• Values defined by NB and NE must be less than or equal to the total
number of trajectory elements.
• The value of NB must be less than that of NE.
• The number of pulses to generate must be greater than 2 and less than
or equal to the Maximum Pulse Number. If not, ET will replace the
desired number of pulses with the Maximum Pulse Number and return
the appropriate error code. In this case, the Maximum Pulse Number
value can be read by the NI? command. If the desired number of pulses
is smaller than the Maximum Pulse Number, NI? returns the specified
value.
The Maximum Pulse Number (MPN) is defined as follows:
MPN = CPTL/[max (2 * max (Encoder resolution of axis X and axis Y)
and (Trajectory velocity * T
base
)]
CPTL (Curvilinear Pulsed Trajectory Length) = Sum of all trajectory ele-
ment lengths between NB and NE.
NOTE
The starting position and the ending position of the axis must be outside
the interval defined with NB and NE commands without forget accelera-
tion and deceleration ranges.
Example:
Generate 11 pulses on a trajectory starting with element number 2 and end-
ing with element number 3:
NT
|
Start defining a new trajectory.
LX10
|
Create element #1.
CR10, CA90
|
Create element #2.
LY20
|
Create element #3.
CX10, CY30
|
Create element #4.
NB2, NE3, NI10.1, NN11
|
Start pulses on element #2, end on element #3 generate 11 pulses
(10 steps), each 0.1 unit.
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