© Technosoft 2007 67 IBL2403 Technical Reference
6.3. Acceleration units
The internal acceleration units are internal position units / (slow loop sampling period)
2
i.e. the
speed variation over one slow loop sampling period.
6.3.1. Brushless / DC brushed motor with quadrature encoder on motor
The internal acceleration units are encoder counts / (slow loop sampling period)
2
. The
correspondence with the load
acceleration in SI units is:
]IU[onAccelerati_Motor
TTrlines_encoder_No
]SI[onAccelerati_Load ×
×××
π×
=
2
4
2
where:
No_encoder_lines – is the rotary encoder number of lines per revolution
Tr – transmission ratio between the motor displacement in SI units and load displacement in SI
units
T – is the slow loop sampling period expressed in [s]. You can read this value in the “Advanced”
dialogue, which can be opened from the “Drive Setup”
6.3.2. Brushless motor with linear Hall signals
The internal acceleration units are counts / (slow loop sampling period)
2
. The motor is rotary. The
position resolution i.e. number of counts per revolution is programmable as a power of 2 between
512 and 8192. By default it is set at 2048 counts per turn. The correspondence with the load
acceleration in SI units
28
is:
For rotary motors:
]IU[onAccelerati_Motor
TTrresolution
]SI[onAccelerati_Load ×
××
π×
=
2
2
For linear motors:
2
Pole_Pitch
Load_Acceleration[SI] = ×Motor_Acceleration[IU]
resolution× Tr × T
where:
resolution – is the motor position resolution
Tr – transmission ratio between the motor displacement in SI units and load displacement in SI
units
28
SI units for acceleration are [rad/s
2
] for a rotary movement, [m/s
2
] for a linear movement