Omron XTRADRIVE

XtraDrive User Manual Chapter 5: Parameter Settings and Functions
5-93
Example
:
A rotary motion system uses a motor with a 17-bit encoder. The user
wants to program the system in speed units of rpm:
17-bit encoder produces 131072[counts] per revolution.
U=131072
1[minute]=60000[ms]
T=60000
1[rpm] =
[]
rdenominato ratio units Speed
numerator ratio units Speed
][60000
][131072
][
][
==
ms
counts
msT
countsU
First option:
Second option:
Both options are equivalent.
5.9.1.4. Acceleration Units
Use the following parameters to convert acceleration units from
[encoder counts/(10msec)
2
] to [user acceleration units]:
Parameter
Setting
Range
Default
Setting
Signal
Pn2B8 1-65535 1 Acceleration units ratio numerator
Pn2B9 0-16383 0 Acceleration units ratio numerator (high bits*)
Pn2BA 1-65535 1 Acceleration units ratio denominator
Pn2BB 0-16383 0 Acceleration units ratio denominator (high bits*)
Acceleration user units are calculated according to the formula:
1[User acceleration unit] =






=
∗
rdenominato
ratioon Accelerati
numerator ratioon Accelerati
])10[(
][
22
msT
countsU
where:
U - represents the number of encoder counts in one acceleration unit.
T - represents the time of acceleration unit in (10*ms)
It is possible to reduce the
fraction so that both the
numerator and denominator are
smaller than 65536:
131072 / 60000 = 32768 /15000
Æ Reduction
Pn2B4 = 32768
Pn2B5 = 0
Pn2B6 = 15000
Pn2B7 = 0
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
Pn2B4 = 0
Pn2B5 = 2
Pn2B6 = 60000
Pn2B7 = 0