Overtravel Conditions

The PLCopen A vendor -and product- independent worldwide association active in Industrial Control and aiming at standardizing PLC file formats based on XML. and Pipe Network motion engines can respond to overtravel conditions from the AKD and AKD2G drive In electrical engineering, a drive is an electronic device to provide power to a motor or servo. Control device for regulating the speed, torque and position of a motor. A unit controlling a motor using the current and timing in its coils. family.

• As a safety feature, AKD and AKD2G drives ignore motion commands once an overtravel is detected in the direction The orientation components of a vector in space. of a hardware limit switch Switch limiting the traverse path of the machine. Implemented as n.c. (break) contact. A sensor, typically Hall-effect, optical, eddy current, or mechanical, which is used to sense the end of travel of a linear motion assembly. In addition to preventing over travel, it is frequently used to establish a precision reference..
• The PLCopen or Pipe Network motion engine applies a stop action to axes when these overtravel conditions occur.

Notes

• Generation 1 AKD drives require setting a fieldbus An industrial network system for real-time distributed control (e.g., CAN or PROFIBUS, Sercos®). It is a way of connecting instruments in a plant design. parameter to enable Enable signal for the drive, Hardware-Enable with 24V signal to X8, Software-Enable command by setup Software, fieldbus or permanently set. Both are required for enabling the drive. this behavior.
• The default behavior of the motion engine can be modified by setting these Axis Boolean parameters:
  • Pipe Network = ML_AXIS_PARAM_IGNORE_DRIVE_LIM_STATUS.
  • PLCopen = MC_AXIS_PARAM_IGNORE_DRIVE_LIM_STATUS.
    
• When this parameter is set to TRUE, the motion engine:
  • Ignores the DS-402 status word Bit 11 from the drive.
  • Allows the application to take the appropriate action.
• See Configuring Generation 1 AKD Drives.

Configuring Generation 1 AKD Drives

When using generation 1 AKD drives, bit 14 of the parameter FBUS.PARAM05 must be set high to allow KAS-IDE Kollmorgen Automation Suite - Integrated Development Environment to respond to the hardware limit switches.

See FBUS.PARAM1 TO FBUS.PARAM10.

If FBUS.PARAM05 originally had a value of 0, typing FBUS.PARAM05 16384 would turn on bit 14. Remember to save your drive parameters to flash memory once bit 14 is set, otherwise the behavior will turn off once the drive is power cycled.

Coordinated Motion Behavior

An axis that is part of an axes group issues an emergency stop on the axes group when it experiences an overtravel condition. All axes remain enabled under servo control once the emergency stop action completes. This action puts the axes group into an error state.

To recover from this state:

1. Call MC_GrpReset on the axes group
2. Check the states of the I/O points configured for the positive Position means a point in space which is described by different coordinates. Depending on the used system and transformation it can consist of a maximum of six dimensions (coordinates).This means three Cartesian coordinates in space and coordinates for the orientation. In ACS there can be even more than six coordinates. If the same position is described in different coordinate systems the values of the coordinates are different. and negative limit switches on the drives associated with the axes to figure out which axis and which limit switch cause the error.
3. Command motion in the direction opposite to what was previously commanded.

Pipe Network Behavior

A Pipe Network axis issues a stop action on the axis when it experiences an overtravel condition.

• This is similar to calling MLAxisStop.
• Bit 11 of MLAxisStatus is set and the axis remains enabled under servo control once the emergency stop action completes.
• The axis no longer accepts pipe positions.
• The pipe the axis is connected to continues functioning A function calculates a result according to the current value of its inputs. A function has no internal data and is not linked to declared instances. as before and any master will continue generating new positions.
• The axis which experienced overtravel simply no longer responds to new pipe positions.

To recover from this state, call MLAxisReAlign to realign the axis with the pipe. See the page Restarting Motion with Pipe Network to understand how to accomplish this.

• 
  

• If a hardware limit flag is being triggered at the program The act of performing a sequence of instructions or commands. startup by a Pipe Network axis, MLAxisReAlign may need to be called immediately before motion occurs.

  In this case, the distance to travel should be at least as long as the maximum distance the hardware limit flag can remain active.

PLCopen Behavior

A PLCopen axis issues an emergency stop of the axis when it experiences an overtravel condition.

• The axis remains enabled under servo control once the emergency stop action completes.
• This action puts the axis into the ErrorStop state.
• See PLCopen State Machine.

To recover from this state:

1. Call MC_ResetError on the axis.
2. Command motion in the direction opposite to what was previously commanded.

   If you are uncertain about which direction the axis was traveling in, check the states of the I/O points configured for the positive and negative limit switches on the drive.