This mode operates the motor in Velocity Mode with extended (jerk-limited) ramps. Unlike Velocity Mode (see "Velocity"), the statusword is used in this mode to indicate whether the target speed is reached.
The following bits in object 6040h (controlword) have a special function:
- Bit 8 (Halt): If this bit is set to "1", the motor stops. On a transition from "1" to "0", the motor accelerates with the set start ramp to the target speed. On a transition from "0" to "1", the motor brakes and comes to a standstill.
The following bits in object 6041h (statusword) have a special function:
Bit 10 (target speed reached; Target Reached): In combination with bit 8 in the controlword, this bit specifies whether the target speed is reached, if braking is taking place or if the motor is at a standstill (see table).
Description 0 0 Target speed not reached 0 1 Axis braking 1 0 Target speed within target window (defined in 606Dhh and 606Eh) 1 1 Axis speed is 0
- Bit 13 (Deviation Error): This bit is set in closed loop mode if the slippage error is greater than the set limits (60F8h Max Slippage and 203Fh Max Slippage Time Out).
The following objects are necessary for controlling this mode:
606Bh (Velocity Demand Value):
This object contains the output of the ramp generator, which simultaneously serves as the preset value for the speed controller.
606Ch (Velocity Actual Value):
Indicates the current actual speed.
606Dh (Velocity Window):
This value specifies by how much the actual speed may vary from the set speed for bit 10 (target speed reached; Target Reached") in object 6041h (statusword) to be set to "1".
606Eh (Velocity Window Time):
This object specifies how long the actual speed and the set speed must be close to one another (see 606Dh "Velocity Window") for bit 10 "Target speed reached" in object 6041h (statusword) to be set to "1".
If bit 6 is set to "1" here, the sign of the target speed is reversed.
6083h (Profile acceleration):
Sets the value for the acceleration ramp in Velocity Mode.
6084h (Profile Deceleration):
Sets the value for the deceleration ramp in Velocity Mode.
6085h (Quick Stop Deceleration):
Sets the value for the deceleration ramp for rapid braking in Velocity Mode.
6086h (Motion Profile Type):
The ramp type can be selected here ("0" = trapezoidal ramp, "3" = jerk-limited ramp).
60FFh (Target Velocity):
Specifies the target speed that is to be reached.
- The speed is is limited by 607Fh (Max Profile Velocity) and 6080h (Max Motor Speed); the smaller value is used as the limit.
Objects in Profile Velocity Mode
After the mode is selected in object 6060h (Modes Of Operation) and the "Power State machine" (see "CiA 402 Power State Machine") is switched to Operation enabled, the motor is accelerated to the target speed in object 60FFh (see following figures). The speed and acceleration values are taken into account here; for jerk-limited ramps, the jerk-limit values are also taken into account.
Limitations in the jerk-limited case
The following figure shows the adjustable limits in the jerk-limited case (6086h = 3).
Limitations in the trapezoidal case
This figure shows the adjustable limitations for the trapezoidal case (6086h = 0).