ABB ACSM1 Series, Manual

Page: 62 / 510

Drive control and features
62
Because the drive speed control uses motor speed, a gear function between position
control (load side) and speed control (motor side) is needed. This gear function is
formed from the motor gear function and inverted load gear function. The gear
function is applied to the position control output (speed reference) as follows:
The equation quite often translates to
Parameters 71.07 GEAR RATIO MUL and 71.08 GEAR RATIO DIV are also inputs
of the firmware block POS CONTROL (see page 253 ).
Note: It is emphasised that all position relevant parameters are load side related, eg,
the setting of parameter 70.04 POS SPEED LIM (dynamic limiter speed limitation) of
300 rpm denotes that, with a load gear ratio of 1:10, the motor can run at up to 3000
rpm.
Examples of gear function usage
The following figures demonstrate how the gear functions of the control program are
used.
=
71.07 GEAR RATIO MUL
71.08 GEAR RATIO DIV
Motor speed
Load speed
=
71.07 GEAR RATIO MUL
71.08 GEAR RATIO DIV
22.03 MOTOR GEAR MUL × 60.04 LOAD GEAR DIV
22.04 MOTOR GEAR DIV × 60.03 LOAD GEAR MUL
Drive firmware
Position
control
Position ref.
Speed
control
Gear ratio
71.07 / 71.08
Speed ref.
Speed act.
n1:n2
Position act.
1:1
Load encoder gear
60.03 / 60.04
1:1
Motor encoder gear
22.03 / 22.04
n2:n1
M
Mechanical set-up
Drive
hardware