5.10 Polarity Detection
5.10.1 Restrictions
5-25
5
Device-
S
pecific
S
etting
s
5.10
Polarity Detection
If you use a Linear Servomotor that does not have a polarity sensor, then you must detect the
polarity.
Detecting the polarity means that the position of the electrical phase angle on the electrical
angle coordinates of the Servomotor is detected. The SERVOPACK cannot control the Servo-
motor correctly unless it accurately knows the position of the electrical angle coordinate of the
Servomotor.
The execution timing and execution method for polarity detection depend on the encoder
specification as described in the following table.
5.10.1
Restrictions
Assumed Conditions
The Servomotor will move when you execute polarity detection. The following conditions must
be met before you start.
•
It must be OK to move the Moving Coil about 10 mm.
(If polarity detection fails, the Moving Coil may move approximately 5 cm. The amount of
movement depends on conditions.)
•
The linear encoder pitch must be 100
μ
m or less. (We recommend a pitch of 40
μ
m or less
for an incremental encoder.)
•
As much as possible, the motor must not be subjected to an imbalanced external force. (We
recommend 5% or less of the rated force.)
•
The mass ratio must be 50x or less.
•
The axis must be horizontal.
•
There must be friction equivalent to a few percent of the rated force applied to the guides. (Air
sliders cannot be used.)
Encoder
Specification
Polarity Detection Execution Timing
Polarity Detection Execution Method
Incremental
encoder
Each time the control power supply to the
SERVOPACK is turned ON
(Even after you execute polarity detection,
the position of the polarity will be lost the
next time the control power supply to the
SERVOPACK is turned OFF.)
•
Start polarity detection when the servo is
turned ON in the SVD.
•
Use the polarity detection function of the
S.
Absolute
encoder
Only for initial setup, or after the SERVO-
PACK, linear encoder, or Servomotor has
been replaced
(The results of polarity detection is stored in
the absolute encoder, so the polarity posi-
tion is not lost when the control power sup-
ply is turned OFF.)
•
Use the polarity detection function of the
S.
•
Enable polarity detection (Pn587 =
n.
1) and then use the servo ON
command from the SVD.
If you use a Linear Servomotor that does not have a polarity sensor, you will not be able to
turn ON the servo until polarity detection has been completed.
Information
