Axis Parameters

The table below is a list of Boolean parameters currently supported. These parameters are read and written by the function blocks MC_ReadBoolPar and MC_WriteBoolPar.

Parameter ID Name R/W Update Rate Type Description
MC_AXIS_PARAM_IN_POSITION 1011 Axis In-Position Read Only Controller True if the axis has no active or next move queued, the command delta is 0, and the actual position is within the in-position bandwidthClosedIn computer networking, bandwidth often refers to a data rate measured in bits/s, for example, network throughput. The reason for the connection of data rate with the term bandwidth is that the limit to the data rate of a physical communication link is related to its bandwidth in hertz of the command position.

False otherwise, Boolean.
MC_AXIS_PARAM_DRIVE_WARNING 1013 Drive Warning Read Only EtherCAT Cyclic Drive Warning Status. 1
MC_AXIS_PARAM_REGIST_GOOD 1025 Good Registration Mark Occurred Read Only EtherCAT Non-Cyclic True indicates that a good registration mark was encountered. This Boolean will be automatically reset after it has been read. 2
MC_AXIS_PARAM_REGIST_BAD 1026 Bad Registration Mark Occurred Read Only EtherCAT Non-Cyclic True indicates that a bad registration mark was encountered. This Boolean will be automatically reset after it has been read. 2
MC_AXIS_PARAM_FI_OCCURRED 1027 Fast InputClosedThe inputs are taken into account at each cycle depending on the system periodicity (for example each millisecond). Under certain circumstances this can be insufficient when more accuracy is needed, or if a quick response is required from the system. To fill the gap, a drive may have some Fast Input connections (generally one or two). When an event happens that triggers a Fast Input (e.g. when a sensor sends a rising edge), the detection of a signal occurs faster (which can be 1000 times more accurate than the system periodicity). Then the timestamp associated with this input can be provided to the IPC to take corrective action Occurred Read Only EtherCAT Non-Cyclic This parameter is deprecated. The recommended replacement is to use the "Done" output of the MC_TouchProbe function block to verify if the fast inputClosedThe inputs are taken into account at each cycle depending on the system periodicity (for example each millisecond). Under certain circumstances this can be insufficient when more accuracy is needed, or if a quick response is required from the system. To fill the gap, a drive may have some Fast Input connections (generally one or two). When an event happens that triggers a Fast Input (e.g. when a sensor sends a rising edge), the detection of a signal occurs faster (which can be 1000 times more accurate than the system periodicity). Then the timestamp associated with this input can be provided to the IPC to take corrective action has occurred.
Deprecated behavior: True if a fast input occurred on either Capture Engine 0 or Engine 1. This Boolean will automatically reset after it has been read. 3
MC_AXIS_PARAM_APPLY_SUPERIMPOSED_DISTANCE 1033 Apply Superimposed Distance Read / Write Controller

If false, MC_MoveAbsolute does not take into account any added superimposed distance due to MC_MoveSuperimp. The final reported position of the axis, which does include superimposed distance, may not be equal to the Position input to MC_MoveAbsolute. 

Param 1033             = False
MC_MoveSuperimp move 1     +50
MC_MoveSuperimp move 2     -35
MC_MoveAbsolute            125 
(superimposed distance = 50-35 = 15)
End Position             = 140

If true, MC_MoveAbsolute compensates for all added superimposed distance from MC_MoveSuperimp calls at the time of the initial MC_MoveAbsolute call. The final reported position of the axis will be equal to the Position input to MC_MoveAbsolute. If MC_MoveSuperimp is called during MC_MoveAbsolute, then the final position will include the superimposed distance.

Param 1033              = True
MC_MoveSuperimp move 1     +50
MC_MoveSuperimp move 2     -35
MC_MoveAbsolute            125
End Position             = 125

The default value for this parameter is False.

The table below is a list of non-Boolean parameters currently supported. These parameters are read and written by the function blocks MC_ReadParam and MC_WriteParam.

Parameter ID Name R/W Update Rate Type Description
MC_AXIS_PARAM_CMD_POS 1 Command Position Read Only Controller

Axis command position – includes any command deltas from superimposed axes, user units.

If a set position is in process (due to homing or registration, there may be a 1 cycle delay.
MC_AXIS_PARAM_ACT_VEL 10 Actual Velocity Read Only EtherCAT Cyclic Axis actual velocity, User unit/sec
MC_AXIS_PARAM_CMD_VEL 11 Command Velocity Read Only Controller Axis command velocity – includes any command deltas from superimposed axes, User unit/sec
MC_AXIS_PARAM_PHASE_SHIFT 1000 Phase Shift Read Only Controller The amount of phase shift applied by MC_Phasing, in slave axis' user units
MC_AXIS_PARAM_SUPERIMPOSED_DISTANCE 1001 Superimposed Distance Read Only Controller The cumulative distance traveled via MC_MoveSuperimp moves, user units
MC_AXIS_PARAM_MASTER_OFFSET 1002 Master Offset Read / Write Controller Write: the amount to increment the master offset for an active master/slave move, user units.

Read: the amount of master offset applied, user units.
MC_AXIS_PARAM_SLAVE_OFFSET 1003 Slave Offset Read / Write Controller Write: the amount to increment the slave offset for an active master/slave move, user units.

Read: the amount of slave offset applied, user units.
MC_AXIS_PARAM_MOVE_TYPE_ACTIVE 1004 Active Move Type Read Only Controller The active move type (see table in Move Types)
MC_AXIS_PARAM_MOVE_TYPE_NEXT 1005 Next Move Type Read Only Controller The queued (next) move type (see table in Move Types)
MC_AXIS_PARAM_POSITION_ERROR 1006 Position Error Read Only EtherCAT Cyclic Position error in user units
MC_AXIS_PARAM_FEEDBACK_LAST 1007 Raw Feedback Read Only EtherCAT Cyclic Raw Feedback position in user units. Keeps track of the actual position based on the physical feedback deviceClosedA process whereby some proportion of the output signal of a system is passed (fed back) to the input. In automation, a device coupled to each motor to provide indication of the motor's shaft angle, for use in commutating the motor and controlling its speed and position connected to the drive and will not be offset as a result of calling MC_SetPos.
MC_AXIS_PARAM_ROLLOVER_POSITION 1008 Rollover Read / Write Controller The axis rollover position in user units. If the axis is a servo axis, this parameter can only be written when there are no moves in the queue. 1
MC_AXIS_PARAM_VELCOMP_FACTOR 1009 Velocity Compensation Factor Read / Write Controller The factor used to multiply the velocity compensation value to account for the number of updates of delay in transmission of the feedback value from the drive to the control. See Velocity Compensation for more information. 1 4
MC_AXIS_PARAM_VELCOMP_FILTER 1010 Velocity Compensation Filter Read / Write Controller The number of updates in which to apply a change in velocity compensation. See Velocity Compensation for more information. 1 4
MC_AXIS_PARAM_IN_POSITION_BAND 1012 Axis In-Position BandwidthClosedIn computer networking, bandwidth often refers to a data rate measured in bits/s, for example, network throughput. The reason for the connection of data rate with the term bandwidth is that the limit to the data rate of a physical communication link is related to its bandwidth in hertz Read / Write Controller The bandwidth about the command position to determine the state of the in-position flag. 2
MC_AXIS_PARAM_DRIVE_STATUS 1014 Drive Status Read Only EtherCAT Cyclic

Drive Status Word (Similar to MLAxisStatus)

Some status bits are set only at program startup.
MC_AXIS_PARAM_UU_FB_RATIO_NUM 1015 User Unit to feedback unit ratio numerator Read Only Static The numerator of the user-units-to-feedback-units ratio (UU/FBU Ratio). See About the User Units to Feedback Units Ratio below. 1
MC_AXIS_PARAM_TORQUE_ACTUAL 1016 Actual TorqueClosedTorque is the tendency of a force to rotate an object about an axis. Just as a force is a push or a pull, a torque can be thought of as a twist Read Only EtherCAT Cyclic The actual torqueClosedTorque is the tendency of a force to rotate an object about an axis. Just as a force is a push or a pull, a torque can be thought of as a twist being delivered by the drive, expressed in thousandths of max torque. See Example of reading the current to units of Amps.
MC_AXIS_PARAM_BUS_ADDRESS 1017 Drive Address Read Only Static Drive address value to be used in EtherCAT fieldbus functions as drive address. Before using in fieldbus functions, this value needs to be converted to integer by using a convert any to DINT function. 1
MC_AXIS_PARAM_SENSOR_DELAY 1018 SensorClosedA sensor is a type of transducer that converts one type of energy into another for various purposes including measurement or information transfer Delay Read / Write Controller Compensation for Physical sensorClosedA sensor is a type of transducer that converts one type of energy into another for various purposes including measurement or information transfer delay for MC_TouchProbe, in microseconds. 1
MC_AXIS_PARAM_INTERP_CMD_POS 1019 Interpolated Command Position Read Only Controller Command position solely from this axis’s interpolator (in user units). This value does not include any command deltas from other axes that are currently superimposed upon it.
MC_AXIS_PARAM_INTERP_CMD_VEL 1020 Interpolated Command Velocity Read Only Controller Command velocity solely from this axis’s interpolator (in user units). This value does not include any command deltas from other axes that are currently superimposed upon it.
MC_AXIS_PARAM_REGIST_COMP 1021 Registration Compensation Read Only Controller The latest calculated registration compensation value. This value is updated each time a good registration mark is encountered. This value is in User Units.
MC_AXIS_PARAM_REGIST_DIST 1022 Distance Between the Last Two Good Registration Marks Read Only EtherCAT Non-Cyclic Distance between the last two good registration marks. This value is in User Units. 2
MC_AXIS_PARAM_REGIST_GOOD_CNT 1023 Number of Consecutive Good Registration Marks Read / Write EtherCAT Non-Cyclic Number of consecutive good registration marks. This value is incremented each time a good registration mark is encountered and automatically zeroed when a bad registration mark is encountered. The ability to write this parameter is provided to allow the application to zero this value. 2
MC_AXIS_PARAM_REGIST_BAD_CNT 1024 Number of Consecutive Bad Registration Marks Read / Write EtherCAT Non-Cyclic Number of consecutive bad registration marks. This value is incremented each time a bad registration mark is encountered and automatically zeroed when a good registration mark is encountered. The ability to write this parameter is provided to allow the application to zero this value. 2
MC_AXIS_PARAM_UU_FB_RATIO_DEN 1028 User Unit to feedback unit ratio denominator Read Only Static The denominator of the user-units-to-feedback-units ratio (UU/FBU Ratio). See About the User Units to Feedback Units Ratio below.
MC_AXIS_PARAM_CM_ACT_CMD_POS 1029 Coordinated Motion Applied Command Position Read Only Controller Amount of motion actually applied to the PLCopenClosedA vendor -and product- independent worldwide association active in Industrial Control and aiming at standardizing PLC file formats based on XML axis drive by Coordinated Motion commands.
MC_AXIS_PARAM_CM_CMD_POS 1030 Coordinated Motion Command Position Read Only Controller Amount of motion requested of a PLCopen axis by the Coordinated Motion commands.
MC_AXIS_PARAM_INGEAR_BANDWIDTH 1031 "In Gear" bandwidth Read/Write Controller The bandwidth about the target slave velocity in which the slave axis will lock onto the master axis and the "InGear" output will turn on for the MC_GearIn function block; User unit/sec (Default value 0.1 User units/sec). 1
MC_AXIS_PARAM_DRIVE_AXIS_NUMBER 1032 Drive Axis Number Read Only

Static

One-based number that specifies the axis on the drive
MC_AXIS_PARAM_UU_FB_RATIO 1034 User unit to feedback unit ratio Read Only Static The user units to feedback units ratio for the axis. See About the User Units to Feedback Units Ratio below.
  1. This is a configuration parameter.
  2. There is some delay is acquiring fast input information from drives as well as calculating the registration marks. While the information is evaluated cyclically, there may be a few cycles between when the fast input occurs and the system records the registration marks. Please see Tuning Controller Performance for EtherCAT Communication Latency for more details.
  3. There is some delay is acquiring fast input information from drives as well as calculating the fast input position. While the information is evaluated cyclically, there may be a few cycles between when the fast input occurs and the system records the fast input data. Please see Tuning Controller Performance for EtherCAT Communication Latency for more details.
  4. There is some delay in acquiring the actual position values. While the information is evaluated cyclically, there may be a few cycles between when the actual position is updated in the drive and the system records the fast input data. Please see Tuning Controller Performance for EtherCAT Communication Latency for more details.
Update Rate Type Description
EtherCAT Cyclic Update rate depends on the EtherCAT (link to ECAT update page EtherCAT Master Settings Tab) and KAS application program (link to Define the PLC Cycle) update rates
EtherCAT Non-Cyclic Update rate depends on the update rate of reading the parameter through Ethercat (Link to times to read non-cyclic parameters [? does the time come from ECATReadSDO FB or from the MCReadParam DriveReadParam FB EtherCAT Library]) and KAS application program update rate
Controller Update rate depends on KAS application program update rate (link to Define the PLC Cycle)
Static Values do not change after axis is created.

  • About the User Units to Feedback Units Ratio

    Parameters 1015 and 1028 are set during the MC_CreatePLCAxis function block execution. These two parameters work together to form the User Units to Feedback Units Ratio (UU/FBU Ratio). The drive interface units are fixed by the drive and define the drive units per revolution, which is used to command the drive per the ratio.

    For a drive where the drive interface units are set to 1048576 units per revolution, the value of the UU-per-revolution ratio can be calculated as follows:

    UU per revolution = MC_AXIS_PARAM_UU_FB_RATIO_NUM * 1048576 / MC_AXIS_PARAM_UU_FB_RATIO_DEN

    Example

    For a drive:

    • A ratio of 360 UU / 1048576 FBU will generate 360 UU per revolution of the drive motor and a 0.000343323 UU-to-FBU ratio.
    • A ratio of 11379 UU / 1898996404 FBU will generate 6.283185 UU per revolution of the drive motor and a 5.99211e-6 UU-to-FBU ratio.

After reading the current via MC_ReadParam, the following equation converts current to amps for a 12 amp peak drive:

MC_AXIS_PARAM_TORQUE_ACTUAL * Drive Peak Current Rating / 1000

Concept Link IconSee Also