MC_CalcDynamicsByRampTime

The MC_CalcDynamicsByRampTime function block is used to calculate the acceleration, deceleration and jerk dynamic parameters, which are required to achieve a specified velocity in a defined time.

The function block assumes that the specified velocity can actually be achieved. If the calculated dynamic parameters are used on a short travel distance, the achieved velocity and the associated acceleration time may be smaller. The function block calculates the acceleration ramp and outputs an identical value as deceleration.

The calculated acceleration, deceleration and jerk dynamic parameters can be used with all MC_Move... function blocks, as well as MC_Halt and MC_Stop.

Inputs

VAR_INPUT
    Velocity     : LREAL;
    RampTime     : LREAL;
    Stiffness    : LREAL;
END_VAR

Name	Type	Description
Velocity	LREAL	Velocity to be achieved
RampTime	LREAL	Time required to achieve the velocity.
Stiffness	LREAL	Stiffness of the acceleration profile [0..1]. A large value means higher jerk in the profile.

Outputs

VAR_OUTPUT
    Error        : BOOL;
    ErrorID      : UDINT;
    Acceleration : LREAL;
    Deceleration : LREAL;
    Jerk         : LREAL;
END_VAR

Name	Type	Description
Error	BOOL	TRUE, if an error occurs.
ErrorID	UDINT	If the error output is set, this parameter supplies the error number.
Acceleration	LREAL	Calculated acceleration
Deceleration	LREAL	Calculated deceleration (Deceleration=Acceleration)
Jerk	LREAL	Calculated jerk

Examples

t₁: internal acceleration ramp time / jerk time

t₂: internal constant acceleration time

t : acceleration ramp time, t = 2 t₁ + t₂

c_s = 0% ‎→ t₁ = ½ t t₂ = 0

c_s = 50% → t₁ = t₂ = 1/3 t

c_s = 99% → t₁ = 0 t₂ = t

Requirements

Development environment	Target platform	PLC libraries to include
TwinCAT v3.1.4024.42	PC or CX (x86 or x64)	Tc2_MC2