YASKAWA SGDV - Page 179

5 Operation
5.9.6 Absolute Encoder Reception Sequence
5-72
Initial incremental pulses:
Outputs pulses at the same pulse rate as when the motor shaft rotates from the origin to the current position at
about 1.215 min
-1
(for 20 bits when the encoder output pulse (Pn212) is at the factory setting)
When the encoder output pulse (Pn212) is not same as the factory setting, use the following formula.
Just as with normal incremental pulses, initial incremental pulses which provide absolute data are first divided
by the frequency divider inside the SERVOPACK and then output.
Final absolute data P
M
is calculated by following formula.
P
E
=M× R+P
O
P
S
=M
S
× R+P
S
’
P
M
=P
E
-P
S
6.528
×
10
8
2
(encoder output pulse)
×
2
×
Pn212
Coordinate
value
Value M
Reference position (setup)
-1 0 +1 +2 +3
+2
Current position
+1
±0-1
P
E
P
M
P
S
P
O
M

R
Signal Meaning
P
E
Current value read by encoder
M Rotational data
P
O
Number of initial incremental pulses
P
S
Absolute data read at setup (This is saved and controlled by the host controller.)
M
S
Rotational data read at setup
P
S
’
Initial incremental pulses read at setup
P
M
Current value required for the user’s system.
R Number of pulses per encoder revolution (pulse count after dividing, value of Pn212)