EtherCAT Master Settings tab

This tab includes configurations for the EtherCAT bus master.

EtherCAT Cycle Time

Figure 1: EtherCAT Master Settings tab

Item

Description

Cycle Time (µs)

Duration of one cycle in microseconds to define the time base period for scheduling the motion and the PLC programs.

Available times are:

  • 250
  • 500
  • 1000
  • 2000
  • 4000

Frame Size

The total size (in bytes) of the EtherCAT frame sent cyclically.

  • The size is proportional to the number of EtherCAT slaves (and consequently the PcDO data) on the network.
  • The EtherCAT frame size is between 84 to 1500 bytes.

Transmit Time

The time (in microseconds) that it takes to send a frame.

Bandwidth Usage
  • An estimation of the percentage of the cycle time used to transmit a frame of data.
  • Bandwidth value goes up when cycle time decreases (see calculation below)

Working Counter Error Limit

A configurable threshold for generating an E30 error and shutdown of EtherCAT communication.

  • The default setting is 3 Errors in 1000 frames.
  • Other options are:
    • Trigger on 1st Error
    • 2 Errors in 1000 frames
    • 10 Errors in 1000 frames
    • 100 Errors in 1000 frames
    • Disabled
      • If the Disabled option is selected, the Master keeps the EtherCAT network running in op mode.
  • It is up to the application to decide if it is appropriate to shut down the Master’s EtherCAT communication (MLMotionStop).
    • The slave device state for EtherCAT communication errors is determined by the manufacturer.
    • AKD drives transition to Init state when 7 consecutive packet failures are encountered and the drive executes a controlled stop.

See Working Counter.

The read-only fields show (unknown) when the Use imported file check box is selected.

Otherwise, they are recalculated and refreshed each time:

  • A device is added or removed.
  • A device simulation state changes.
  • The Use imported file check box is cleared.

See ENI File tab.

Bandwidth Calculation Algorithm

The Bandwidth (BW) usage calculation takes into account the calculated frame size and the Ethernet speed (100 Megabits per second).

BW% = Transmission time / Cycle Time

With Transmission time (μsec) = (Frame Size in bytes * 8) bits / 100 * 106 bps

Example

If Frame Size = 100 bytes 
then Transmission Time = 100*8 / (100*106 ) = 8 μsec
If cycle time = 1000 μsec
then BW% = 8/1000 = 0.8 %