CSP (position control)

CSP is the abbreviation for "Cyclic Synchronous Position".

The CSP operation mode is set in 0x7010:03 "Modes of operation" as described in "Setting the operation mode".

The Predefined PDO Assignment "Position" is set as described in "Selection of process data".

1. Setting the target position
A defined target position can be set via the process data "Target position".

CSP (position control) 1: — Setting the target position via the "Target position" process data

	Cycle time For all operation modes, the cycle time must be an integer multiple of 62.5 µs, at least 125 µs. When using the drive motion control (DMC), the cycle time must not be faster than 250 µs.

With the settings for the operating mode CSP the EtherCAT plug-in module calculates internally the control loops for current, velocity and position. The NC calculates the setpoint specification of the position and transfers it to the module.

1. Setting the following error monitoring

Furthermore, there is an option in CSP mode to activate a following error monitoring. The following error monitoring is switched off on delivery. In all other modes this is not used and is ignored.

Proceed as follows to set the following error monitoring:

Notice

Risk of damage to the device!

We strongly advise not to change settings in the CoE objects while the axis is active, since this could impair the control.

Click on the "CoE-Online" tab

CSP (position control) 3: — "Following error window" (0x8010:50), "Following error time out" (0x8010:51)

1. The window of the following error monitoring can be adjusted with the Following error window (index 0x8010:50).

The value set here – multiplied by the scaling factor – specifies by what position the actual position may differ from the set position, positively and negatively. The total accepted tolerance is thus twice as large as the position entered in the Following error window (see fig. Following error window).
The value 0xFFFFFF (-1) in the Following error window means that the following error monitoring is switched off and corresponds to the delivery state.

CSP (position control) 4: — Following error window

2. Use the Following error time out (index 0x8010:51) to set the time (in ms) allowed for a following error timeout.

As soon as the set position is exceeded by more than the position entered in the Following error window for the time entered in the Following error time out, the terminal outputs an error and stops immediately.
The Following error time out is 0x0000 (0) in the delivery state.

The current following error can be read via the process data Following error actual value.

Notice

Changes in the CoE directory (CAN over EtherCAT), program access

When using/manipulating the CoE parameters observe the general CoE notes in chapter "CoE interface" of the EtherCAT system documentation:

Keep a startup list if components have to be replaced,
Distinction between online/offline dictionary,
Existence of current XML description (download from the Beckhoff website),
"CoE-Reload" for resetting the changes
Program access during operation via PLC (see TwinCAT3 | PLC Library: Tc2_EtherCAT and Example program R/W CoE)

Example of motion command with following error monitoring

CSP (position control) 5: — Following error over time

1. When accelerating, the following error increases.

2. The set limit value for the following error (following error window) is exceeded.
The duration of the exceedance of the following error window (shown in gray in the figure above) is shorter than the period specified in following error timeout (shown in green in the figure above).

No error is triggered.

3. The following error decreases to zero as soon as the target position is reached.
In the event of a blockage of the axis (e.g. end stop), target position continues to run, while feedback position stops.

The following error increases.

4. The following error exceeds the limit value Following error window for a longer period than specified in following error timeout.

After expiration of following error timeout an error is triggered (fault reaction).