Emerson SM-ETHERCAT 0471-0128-02 - Manual (Page 46)

46
SM-EtherCAT User Guide
www.controltechniques.com Issue Number: 2
The object vl_velocity_min_max is handled every profile cycle. The vl_target_velocity is
limited according to the values set in the object vl_velocity_min_max, which is read
every profile cycle. The object vl_velocity_min_max_amount is mapped to
vl_velocity_min_max.
The value of the vl_velocity_demand object is calculated in the background. The option
reads the value of parameter Pr 2.01 (post ramp reference), scaled from RPM to user
units using vl_dimension_factor and vl_setpoint_factor, and writes the value to the
vl_velocity_demand object.
On a closed-loop drive, the speed feedback is read from the drive internally every profile
cycle, scaled to the same units as vl_target_velocity and written to the
vl_velocity_actual_value object. On an open-loop drive, the estimated motor speed is
read from Pr 5.04 (motor RPM) in the background, scaled to the units of
vl_target_velocity and written to the vl_velocity_actual_value object.
The vl_velocity_acceleration and vl_velocity_deceleration objects are handled in the
background. They are read, scaled to drive acceleration units (depending on the drive
operating mode), and written to the drive acceleration rate and deceleration rate
presets. In addition, if the drive acceleration rate preset is changed, the
vl_velocity_acceleration object is updated, and if the drive deceleration rate preset is
changed (Pr 2.21), the vl_velocity_deceleration object is updated.
7.6 Profile Torque mode
The profile torque mode is supported on Unidrive SP, Digitax ST, Affinity, Mentor MP
and Commander SK. It is possible to use this profile in regen mode on the Unidrive SP.
On the Unidrive SP and Digitax ST in closed-loop or servo mode, this mode operates on
the profile cycle time, using the drives internal torque shortcut (which is read by the
drive every 250µs). On the Commander SK, Unidrive SP and Affinity in open-loop
mode, the torque reference is written to the drive user torque parameter, which is
handled every 4ms. When using profile torque mode object 0x604A
vl_velocity_quick_stop will be used in the event of a quick stop (also for quick stop
option codes 2 and 6 the 0x6049 vl_velocity_deceleration object will be used).
Table 7.47 shows the objects that are supported:
7.6.1 0x6071 Target_torque
This object indicates the configured input value for the torque controller in profile torque
mode. The value of this object is given per thousand of rated torque.
Table 7.47 Profile torque mode supported objects
Index Name
0x6071 Target_torque
0x6075 Motor_rated_current
0x6078 Current_actual_value
0x6087 Torque_slope
Table 7.48 0x6071 Target_torque
0x6071 Target_torque
Access: RW Range: -32768 to +32767 Size: Signed 16 Unit: 0.1% of rated torque
Default: 0
Description: Indicates the configured input value for the torque controller in profile torque mode.