YASKAWA SGD7S-1R9D, Руководство по эксплуатации продукта

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6.8 Absolute Encoders
6.8.6 Calculating the Current Position in Machine Coordinates
6-35
6
Application Functions
6.8.6 Calculating the Current Position in Machine Coordinates
When you reset the absolute encoder, the reset position becomes the reference position.
The host controller reads the coordinate Ps from the origin of the encoder coordinate system. The host
controller must record the value of coordinate Ps.
This section describes the reference position in the machine coordinate system.
The method to calculate the coordinate value of the present position from the origin of the machine
coordinate system is given below.
The current position P
M
in the machine coordinate system is calculated as follows:
P
M
= P
E
- P
S
P
E
= M
×
R + P
O
P
S
= M
S
×
R + P
S
’
Note: The following formulas apply in Reverse Rotation Mode (Pn000 = n.

1).
P
M
= P
E
- P
S
P
E
= -M
×
R + P
O
P
S
= M
S
×
R + P
S
’
Symbol Meaning
P
E
Position data for the current position of the absolute encoder
M Current position of the multiturn data of the absolute encoder
P
O
Position of the current position within one rotation
P
S
Position data of the absolute encoder when absolute encoder was reset
M
S
Multiturn data of the absolute encoder when absolute encoder was reset
P
S
’
Position of the absolute encoder within one rotation when absolute encoder was reset
P
M
Current position in machine coordinate system
R Pulses output per encoder rotation (value after dividing; setting of Pn212)
1. If you are using a Rotary Servomotor, you must reset the absolute encoder. Refer to the fol-
lowing section for information on resetting the absolute encoder.
5.15
Resetting the Absolute Encoder
on page 5-49
2. You can set the origin to a different position from the reset position. Refer to the following sec-
tion for information on the origin position offset.
5.16
Setting the Origin of the Absolute Encoder
on page 5-52
Machine coordinate
Value of
multiturn data
-1 0 +1 +2 +3
-1
±0
+1 +2
Origin (reference position) Current position
M × R
P
E
P
O
P
S
P
M
Information