EDH0162En1040 – 06/99
6.6
MM4005
Feature Descriptions Tutorial
NS
|
Enable the signal generation.
ET
|
Execute the trajectory.
TQ
|
Read position of every pulse generated.
During the execution of a trajectory with such synchronized signals, each
time a pulse is generated, the real and theoretical position of all axes is
recorded in the global position buffer that could be read with the TQ com-
mand. The NS command thus terminates the effect of a previously entered
GQ command. To enable the global trace mode after a trajectory with syn-
chronized pulses, the GQ command must be re-issued.
A pulse is generated automatically as soon as the trajectory execution
reaches position:
Pulse position = Pos(NB) + (n * Step) with stage position
∈
[NB … NE]
where: Step = CPTL/(NI - 1)
The position accuracy of the generated pulse (the difference between the
theoretical position Pos(NB) + n * Step and the real position where the
pulse is generated) depends on the trajectory velocity as follows:
MaxError = ± 0.707 * (T
base
* Trajectory velocity)
This value cannot be smaller than the encoder resolution of X or Y axis.
If
MaxError < encoder resolution of X axis.
then
MaxError = encoder resolution of X axis.
If
MaxError < encoder resolution of Y axis.
then
MaxError = encoder resolution of Y axis.
Example
For a trajectory velocity of 20 mm/sec and T
base
= 300 µsec:
MaxError = ±0.707 * (3 * 10
-4
* 20) = ±4.24 µm
This position uncertainty exists for every pulse generated but is not cumu-
lative.
6.1.3
Synchronizing Events to Trajectory Elements
Controller operations and functions can be synchronized to the execution
of a trajectory element. This is achieved by using the WNnn command.
The nn parameter represents the trajectory element number to synchro-
nize with. At the beginning of this element, one or more secondary con-
troller activities could be initiated.
Example
Increase the trajectory velocity starting with element number 2 and reduce
it with element number 4.
1XX
|
Erase program #1 (if exists).
1EP
|
Start program entry mode.
NT
| Start new trajectory definition.
LX10
|
Trajectory element #1.
CR10, CA90
|
Trajectory element #2.
LY20
| Trajectory element #3.
CX10, CY30
| Trajectory element #4.
LX0
| Trajectory element #5.
CX0, CY0
|
Trajectory element #6.
VV5
| Set trajectory velocity to 5 mm/sec.
ET
| Execute
trajectory.
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