Application note 0564-06: PDO configuration

Owned by Veronika Tannewitz
May 28, 2021
3 min read

This document explains the procedure to configure a PDO. The communication profile CiA-301 specifies the following steps:

 

step

PDO communication parameter *

PDO mapping parameters **

category

description

  1.  

sub-index 1: set bit 31 of the cob-ID

 

mandatory

Disable the PDO.

 

  1.  

 

sub-index 2-6: change the value

 

 

optional

change the PDO communication parameters:

The sub-index can be configured if:

·         the sub-index exists in the PDO object

·         the sub-index is writeable

·         the new value is allowed for this PDO

 

  1.  

 

 

sub-index 0: set number of PDO mapping entries to 0

 

conditional

change the PDO mapping:

Disable PDO mapping.

The PDO mapping can be changed if:

·         dynamic PDO mapping is allowed for this PDO

·         the sub-indices of the PDO mapping object are writeable

  1.  

 

sub-index 1-64: set the PDO mapping

optional

Specify the PDO mapping. The mapped objects must be mappable into a PDO.

  1.  

 

sub-index 0: set the correct number of PDO mapping entries

conditional

The number of the specified PDO mapping entries in step 4 must be set.

  1.  

sub-index 1: set the desired cob-ID, bit 31 must be set to 0

 

mandatory

Change the cob-ID and

enable the PDO.

*...objects 1400h-15FFh and 1800h-19ffh, **... objects 1600h-17FFh and 1A00h-1BFFh

 

Step 3 and 5 are mandatory if the PDO mapping shall be changed and the conditions are fulfilled.

 

It is allowed to configure a PDO in the state NMT/OPERATIONAL because the PDO is disabled in step 1, i.e. the PDO is not used.

 

Sub-index 2 and 5 if the PDO communication parameters can also be configured when the PDO is enabled.

 

The configuration steps are also valid for the configuration of a PDO via the CAN bus.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Initialization of the PDO cob-ID in an application created with the CANopen Library of port:

The CANopen Library initializes the PDO cob-ID as indicated in Figure 1.

 

 

 

Figure 1: initialization of PDO cob-IDs

Notes to Figure 1:

  1. The initialization of the PDO cob-ID depends on the access right of the PDO communication parameter / cob-ID object, see Design Tool PDO communication parameter object / sub-index cob-ID / Tab Structure / Access.

  1. The option “non-standard extension” of the Design Tool is described in the application note 0640-03.

  1. The CANopen Library initializes the PDO cob-IDs according to the pre-defined connection set. This initialization can be overwritten by the PDO cob-IDs designed in the Design Tool. Call the function overwritePreDefConnSet(), located in the generated C module co_init.c, in your application after calling of init_Library().

  1. The CANopen Library initializes the PDO cob-IDs according to the pre-defined connection set. Application-specific PDO cob-ID have to be set by CANopen Library functions, see the following chapter.

  1. The CANopen Library initializes the PDO cob-IDs with the values designed in the Design Tool.

 

Change PDO cob-IDs with CANopen Library functions:

The function init_Library() initializes the cob-IDs according to pre-defined connection set, defined in CiA-301. When you like to use other cob-IDs you have to change the values of the PDO cob-IDs in your application after the execution of the function init_Library(). There are the following possibilities to configure the PDO cob-IDs, shown for TPDO1:

 

  1. option:

coRetVal = setCobId(0x1800, 1, (PDO_NO_VALID_BIT | cobId) );

coRetVal = setCobId(0x1800, 1, cobId);

 

  1. option:

cobId = PDO_NO_VALID_BIT | cobId;

coRetVal = putObj(0x1800, 1, (UNSIGNED8*)&cobId, size, CO_TRUE);

coRetVal = setCommPar(0x1800, 1);

cobId = (~PDO_NO_VALID_BIT) & cobId;

coRetVal = putObj(0x1800, 1, (UNSIGNED8*)&cobId, size, CO_TRUE);

coRetVal = setCommPar(0x1800, 1);

 

  1. option:

p301_n1_tpdo_para.cobId |= PDO_NO_VALID_BIT;

coRetVal = setCommPar(0x1800, 1);

p301_n1_tpdo_para.cobId &= (~PDO_NO_VALID_BIT);

coRetVal = setCommPar(0x1800, 1);

 

The compiler define PDO_NO_VALID_BIT is already defined in the CANopen Library in the file co_pdo.h:

#define PDO_NO_VALID_BIT 0x80000000

 

 

Change another PDO parameter in an application created with the CANopen Library of port:

Option 2 and 3 can also be used to change the other PDO parameters, i.e.:

  1. Set the value of the PDO parameter in the object dictionary with the function putObj() or directly about the C name of the object.

  1. Activate the setting for the CANopen Library by calling the function setCommPar().