6.7 Selecting the Phase Sequence for a Linear Servomotor
6-20
6.7
Selecting the Phase Sequence for a Linear Servomotor
You must select the phase sequence of the Linear Servomotor so that the forward direction of
the Linear Servomotor is the same as the encoder’s count-up direction.
Before you set the Linear Servomotor phase sequence (Pn080 = n.
X
), check the follow-
ing items.
•
Confirm that the signal from the linear encoder is being received normally.
•
Make sure that the forward direction of the Linear Servomotor and the count-up direction of
the linear encoder are in the same direction.
Related Parameters
Setting Procedure
Use the following procedure to select the phase sequence for a Linear Servomotor.
1.
Set Pn000 to n.
0 (Set a phase-A lead as a phase sequence of U, V, and W).
This setting is to make following confirmation work easier to understand.
2.
Select
Monitor
in the Menu Dialog Box.
The Operation Pane will be displayed so that you can check the feedback pulse counter.
To check the feedback pulse counter with the Digital Operator, use Un00D (Feedback Pulse Counter).
3.
Manually move the Moving Coil from one end to the other of the stroke and confirm that
only the correct number of feedback pulses is returned.
If the correct number and only the correct number of pulses is returned, the signal is being received
correctly from the linear encoder.
If you do not confirm the above items before you attempt to operate the motor, the motor may
not operate or it may run out of control. Always confirm these items before you operate the
motor.
Parameter
Meaning
When Enabled Classification
Pn080
(2080h)
n.
0
(default setting)
Set a phase-A lead as a phase sequence of U, V, and W.
After restart
Setup
n.
1
Set a phase-B lead as a phase sequence of U, V, and W.
In this example, assume that a linear encoder with a scale pitch of 20
μ
m and a resolu-
tion of 256 is used. If you manually move the Moving Coil 1 cm in the count-up direction
of the linear encoder, the number of feedback pulses would be as follows:
1 cm/(20
μ
m/256) = 128,000 pulses
Note: The actual monitor display will be offset by the error in the travel distance. There is no
problem as long as the above value is close to the calculated value.
Important
Example
Cable for Linear
Servomotor Moving Coil
If there are 128,000 pulses on the feedback pulse counter after
you manually move the Moving Coil in the direction of the cable,
you have completed the confirmation.
