Yaskawa FSP Amplifier - Manual (Page 161)

FSP Amplifier User’s Manual Chapter 5: Parameter Settings and Functions
5-94
Acceleration user units are calculated according to the formula:
1 [User acceleration unit] =
⎥⎦
⎤
⎢⎣
⎡
=
∗
r denominato ratio on Accelerati
numerator ratio on Accelerati
] ) 10 [(
] [
2 2 ms T
counts U
where:
U = represents the number of encoder counts in one acceleration unit.
T = represents the time of acceleration unit in (10*ms)
The maximum value of numerator (Pn2B8) or denominator (Pn2BA) is
65535. In cases where greater values are required, it is possible to use
parameters Pn2B9 and Pn2BB for storing the high bits of numerator and
denominator respectively, according to the following formula:
High Bits = HB = Integer part of
65536
N
Low Bits = N – HB * 65536
Where N = required value
Example:
A rotary motion system uses a motor with a 17-bit encoder. The user wants
to program the system in units of rad/s
2 :
17-bit encoder produces 131072[counts] per revolution.
One revolution = 2 π [rad]
U = 131072 / 2 π
1 [s] = 1000[ms] = 100[10*ms] = T
T 2 = 10000
1[rad/sec 2 ] =
( ) [ ] ⎥⎦
⎤
⎢⎣
⎡
= =
∗
=
∗ r denominato ratio units on Accelerati
numerator ratio units on Accelerati
62832
131072
10000 2
131072
2 10
] [
2 π ms T
counts U
Example:
Without reduction of the fraction:
High Bits = HB = Integer part of N/65536 = Integer part of
131072/65536 = 2
Low Bits = N - HB * 65536 = 131072 - 2 * 65536 = 0
Pn2B8 = 0
Pn2B9 = 2
Pn2BA = 62832
Pn2BB = 0