YASKAWA SGD7S series - Setting the Number of External Encoder Scale Pitches; Setting the PAO, PBO, and PCO (Encoder Divided Pulse Output) Signals; Setting the Number of External Encoder Scale

10.3 Parameter Settings for Fully-Closed Loop Control
10.3.3 Setting the Number of External Encoder Scale Pitches
10
Fully-Closed Loop Control
10-7
10.3.3 Setting the Number of External Encoder Scale Pitches
Set the number of external encoder scale pitches per motor rotation in Pn20A.
Setting Example
If the external encoder is connected directly to the motor, the setting will be 1,500 (30 mm/0.02
mm = 1,500).
Note: 1. If there is a fraction, round off the digits below the decimal point.
2. If the number of external encoder scale pitches per motor rotation is not an integer, there will be deviation
in the position loop gain (Kp), feedforward, and position reference speed monitor. This is not relevant for
the position loop and it therefore does not interfere with the position accuracy.
Related Parameters
10.3.4 Setting the PAO, PBO, and PCO (Encoder Divided Pulse
Output) Signals
Set the position resolution in Pn281 (Encoder Output Resolution).
Enter the number of phase A and phase B edges for the setting.
Setting Example
If a single pulse (multiplied by 4) is output for 1 μm, the setting would be 20.
If a single pulse (multiplied by 4) is output for 0.5 μm, the setting would be 40.
The encoder divided pulse output would have the following waveform if the setting is 20.
“↑” indicates the edge positions. In this example, the set value is 20 and therefore the number
of edges is 20.
Note: The upper limit of the encoder signal output frequency (multiplied by 4) is 6.4 Mpps. Do not set a value that
would cause the output to exceed 6.4 Mpps.
If the output exceeds the upper limit, an A.511 alarm (Encoder Output Pulse Overspeed) will be output.
Specifications
External encoder scale pitch: 20 μm
Ball screw lead: 30 mm
Pn20A
Number of External Encoder Scale Pitches
Setting Range Setting Unit Default Setting When Enabled Classification
4 to 1,048,576
1 scale pitch/revo-
lution
32,768 After restart Setup
Number of external encoder
pitches per motor rotation
External encoder
(scale pitch: 20 m)
Workpiece position
after movement
Workpiece position
before movement
Ball screw lead: 30 mm
Position
Specifications
External encoder scale pitch: 20 μm
Ball screw lead: 30 mm
Speed:1,600 mm/s
Phase A
Phase B
Sine wave pitch