L_MC1P: ContinousUpdate with MC_MoveVelocity at cyclic setpoint change not given (corrected from V03.21.00)
Corrected from:
Library: L_MC1P_MotionControlBasic (FAST Motion) from V03.21.00.102 (Update via Package Manager)
Response of the new version:
If continuous transfer of profile parameters is activated (FB input xContinuousUpdate = TRUE), setpoint changes at input Velocity of the MC_MoveVelocity block are now immediately transferred.
What happens?
MC_MoveVelocity: A setpoint change at input Velocity is not immediately accepted despite ContinousUpdate = TRUE if the setpoint changes in each cycle.
Example: The setpoint velocity is controlled via a separate ramp generator and during the duration of an acceleration phase the setpoint changes from cycle to cycle. Duration of the acceleration phase: 100 ms. The MC_MoveVelocity then takes over the setpoint change during the duration of the acceleration phase only with a delay of 100 ms.
When does the behaviour occur?
The behavior occurs when the following conditions coincide
The function for cyclic transfer of the profile parameters is active: FB input xContinuousUpdate = TRUE and
the value at input Velocity is changed in each call cycle of the MC_MoveVelocity.
Which products are affected?
Library: L_MC1P_MotionControlBasic, only version V03.20.00.102 affected.
Short-term measures, Evaluation/Recommendations:
Remedy: This behavior does not occur if the velocity setpoint changes only every second or more call cycles of the MC_MoveVelocity. The delayed acceptance occurs if no setpoint value change has occurred for at least 2 call cycles. After that, the setpoint value to the axis follows directly the Velocity input again, even if this changes again in each call cycle.
The function of the MC_MoveVelocity is embedded as a basic function in AxisBasicControl and thus in every Technology Module (TM). The behavior can therefore also occur in applications where this embedded function is used, such as in the i950 TA Speed Control. If the External Profile Velocity (0x5030:12) were to change every millisecond via fieldbus process data, the described behaviour would be observed. Another use case could be a velocity follower in which the slave is to follow a master via the basic function MC_MoveVelocity.
This behaviour not only results in a delayed acceptance of the setpoint, but a setpoint jump can also occur. Whether a PLC project or also an i950-TA is affected depends on whether the named library version is used. The library version is defined in the device description. If, for example, a device i950 is updated in the PLC project from V01.03.07 to V01.04.01, the library concerned would be included. When using a purely parameterizable i950-TA, it is relevant which i950 firmware is used. In i950 FW V01.04.01 and V01.04.02 the library L_MC1P is included with the restriction. See link.
