Axis Data Parameters

If a Servo axis is selected, two tabs are available: Axis Data and Axis Limits. If a Digitizing axis is selected, only the Axis Data tab is available. By default, new axes will be defined using degrees as the measurement unit.

Servo Axis - Axis Data

Figure 5-22: Servo Axis - Axis Data

The Servo Axis - Axis Data parameters are:

Parameter	Description
Position Unit	This field sets the units (see UNIT Parameters ) used by the drive axis. When the axis is defined as an AKD2G the controller applies the user units value and label to the drive. These user units will be applied for both Op-mode (running application) and Pre-Op mode (online config) when the EtherCATEtherCAT is an open, high-performance Ethernet-based fieldbus system. The development goal of EtherCAT was to apply Ethernet to automation applications which require short data update times (also called cycle times) with low communication jitter (for synchronization purposes) and low hardware costs network is started up. Counts 16 bit Degree Radian Custom - Selecting Custom allows you to specify the User Units value.
User Units / Revolution	The value used to define an axis position or distance for an axis. The default values are: Counts: 65,536 / revolution Radian: 6.28318530717 (or 2π) / revolution Degree: 360 / revolution When the Unit is set to Custom you may enter your own value and units name, such as `gradians`, `centimeters`, or `inches`.
Update Rate	The rate at which the axis's feedback is read and a new command position is generated. The choices are: 250 µsec 500 µsec 1 msec 2 msec 4 msec 8 msec This rate can be slower or equal to the EtherCAT Cycle Time (for more details, click here...) The EtherCAT Cycle Time specifies the rate at which data is transferred between the control and the drives. The axis Update Rate is the rate at which the PLC"Programmable Logic Controller" A Programmable Logic Controller, PLC, or Programmable Controller is a digital computer used for automation of industrial processes, such as control of machinery on factory assembly lines. Used to synchronize the flow of inputs from (physical) sensors and events with the flow of outputs to actuators and eventsopen code reads the feedback, runs its interpolation, and generates a new command position. By allowing some axes to run at a slower rate and staggering the updates on which these axes are interpolated, more axes and/or quicker execution times can be achieved since every axis does not have to be interpolated every update. If you select an axis Update Rate which is faster than the EtherCAT Cycle Time, the axis is set to run at the EtherCAT Cycle Time.
Rollover Position	The value at which the axis position rollovers to zero. Rollover Position is specified in User Units. For example: If the rollover position is 1000, the axis position counts up from 0 to 999 and then rollover back to 0. In the reverse direction, the axis position counts down to 0 and then rollover to 999. If Rollover Position is 0, no rollover occurs. Axis positions become negative values when counting down below 0.