Flexible PDO Mappings

In addition to the fixed PDO mapping the so-called flexible mapping of real-time objects is possible.

Available objects for PDO mapping are listed in the object dictionaries ()(). All objects with the entry "yes" in column "PDO map." can be used.

Restrictions of flexible mapping:

An odd length PDO is not allowed.
In the Rx(=set-point)-direction the dummy-object 0x0002 sub 0 with a length of 8 bits can be used to make the PDO-length even.
In the Tx(=actual value)-direction one sub-index of the manufacturer status object 0x2002 sub 1..4 can be used to guarantee the even length of the Tx-PDO.
These special mappings may be used if the objects 0x6060 and 0x6061 have to be used in the mapping.
The allowed PDOs have up to 32 bytes (Tx) or 20 bytes (Rx). They are built from smaller PDO modules with a maximum length of 8 bytes. These are built by using the mapping objects 0x1600 to 0x1603 and 0x1a00 to 0x1a03.

The configuration is similar to the described sequence for the fixed mappings:

The mapping selection is cleared (write 0 to object 0x1C12 sub 0 and 1C13 sub 0)
As the AKD - implementation is based on CANopen the real-time data are build from up to 4 PDOs with 8 bytes in both directions. These PDOs are built in the same way as in a CAN"Controller area network" CAN is a broadcast, differential serial bus standard developed for connecting electronic control units. Each node is able to send and receive messages, but not simultaneously-drive with the objects 0x1600 - 0x1603 and 0x1A00 - 0x1A03. Unused PDOs must be cleared with writing 0 to the subindex 0.
SDO write access to object 0x1C12 sub 1 .. 4 with the PDOs (0x1600 .. 0x1603), that should be used in receive direction of the AKD (set point values).
SDO write access to object 0x1C13 sub 1 .. 4 with the PDOs (0x1A00 .. 0x1A03), that should be used in transmit direction of the AKD (actual values).
SDO write access to the objects 0x1C12 sub 0 and 0x1C13 sub 0 with the number of mapped PDOs in this direction.

See an example in chapter Flexible PDO Mappings .

The cyclically used data are visible in the PDO-assignment window for the Inputs and Outputs of the Sync Managers. Default setting are the fixed PDOs 0x1701 and 0x1B01 (visible contents when selected in the PDO list).

If the flexible mapping is required, the PDO configuration check box must be changed.

Example: Flexible PDO Mapping

For the flexible mapping of the Outputs the fixed mapping 0x1701 has to be switched off and up to 4 free-mappable PDOs (0x1600-0x1603) can be used instead. The maximum number of bytes for each of these PDOs is 8.

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After that the default mapping of e.g. the PDO 0x1600 can be extended:

A list of possible objects for the mapping will be shown and a new entry can be chosen.


In this case the setpointSetpoint is the target value that an automatic control system, for example PID controller, will aim to reach for the interpolated position mode is selected.	The same is valid for the Tx-PDO-direction. Here the value of the actual internal position is selected.

This results in the startup-SDO-list for this sample free-mapped-configuration.

The meaning of the data (for example 0x60410010 in the mapping of 0x1A00 sub 1) is as follows:

0x6041 is the index of the DS402 status word
0x00 is the subindex of the DS402 status word
0x10 is the number of bits for this entry, i. e. 16 bits or 2 bytes.

If this shall be used in the NC, the interpolation set point position has to be linked from the axis to the NC-axis.

After doing this configuration the mapping can be activated as seen before in this document:

Now the NC-screen should show a position in the online window, which changes a bit in the last digits.

After enabling the power stage with the All-button, the drive can be moved via the jog-buttons or via the functions in the function menu.