Travel range limit switches (hardware limit positions)

The travel range limit switches are provided centrally to the axis data via the two inputs xLimitSwitchPos and xLimitSwitchNeg of the FB L_MC1P_HWLimitSwitchInterface . The two inputs react to the TRUE state and have to be connected to the corresponding digital inputs to which the limit switches are connected.

If one of the two inputs is set to TRUE:

The error message "HWLimitPos" or "HWLimitNeg" is generated, regardless of

any current movement of the axis or

the current direction of movement of the axis.

The output LimitSwitchPos or LimitSwitchNeg of the FB MC_ReadAxisInfo is set to TRUE.

The axis state changes to "ErrorStop", i.e. the axis is braked to a standstill depending on the error response configured in subindex 104 .

The axis can only be traversed again after the error has been acknowledged via MC_Reset .

Response - hardware limits exceeded (subindex 104)

Virtual axis 9400 HighLine i500 inverter i700 servo inverter i950 servo inverter Encoder
Selection list (Lenze setting printed in bold)
19	Error->Fast stop
21	Error->QSP->CINH
Read access Write access Can only be changed in "Disabled" state No download		UNSIGNED_8

Behaviour in case of retracting of limit switches

If a limit switch is set and the error message has been acknowledged, only travel requests in the opposite direction (direction of retraction) are possible. Travel requests in the direction of the limit switch are cancelled with an error.

Verification of the hardware limit switches

Note!

Please note that if the configuration is not correct (e.g. swapping the HW limits between several AxisRefs) no error stop of the axis is triggered.

The verification must therefore only be carried out under manual control. If necessary, limit the manual jogging velocity so that a manual emergency stop can be performed at any time while ensuring machine safety.

To ensure the function of the hardware limit switches, the following manual test is recommended during commissioning after setting up and connecting the digital inputs to the FB:

Check the parameterization of the error stop ramp. The error stop should not lead to the physical limits of the drive or the machine being exceeded, but should still ensure the shortest possible stopping distance.
Move the axis in the positive direction in manual mode (e.g. L_MC1P_AxisBasicControlV2) until the positive limit switch is reached.
The axis is brought to standstill with the parametrized error stop parameters. The LimitSwitchPos output of the FB MC_ReadAxisInfo is TRUE. Check the error message of the axis (HWLimitPos).
Reset the error and release the axis from the limit switch in the negative direction.
Repeat the test in negative travel direction for the negative hardware limit switch

Use of the hardware limit sitches during homing

The signals of the hardware limit switches are used in the referencing modes

to control the homing sequence or to directly determine the homing position.