Demo Master Object Dictionary Access

This linux application tests and demonstrates the access to the object dictionary from a linux master. After startup a automatic test which reads the object dictionary from the selected slave and tests the accessability of read/write and read only objects.


To compile this application simply type


You can find the resulting binary in the newly created bin/ folder.


The applicatin accepts various command line arguments. With -h a short overview of the available options are available.

All the options in detail are:

  • -h a short list of the available objects
  • -l show a list of all connected slaves and exit
  • -m <index> select the master with numerical index (value range: 0 .. n), if more than one master is available (default: 0)
  • -n <index> select the slave to use for testing (index rage: 0 .. n) (default: 0)

After the application starts first the object dictionary on the slave is uploaded and displayed on the console. If this is successful the application tries to download values to the specified device and re-upload the value from the device object dictionary. The test succeeds if:

  1. the uploaded value is the same as the one previously downloaded if the object entry is writeable
  2. the uploaded value is different from the previous downloaded value if the object entry is read only

Please note in the later case the EtherCAT master gives a warning that you tried to write a read only value.


If you run the application without any options the master 0 and slave 0 is used. All other master and devices are ignored


To get a list of all slaves which are connected to the master run

./bin/app_demo_master_object_dictionary -l

If there is more than one slave active on the bus and you want to request the 4th device you run

./bin/app_demo_master_object_dictionary -n 3

Since the device enumeration starts with 0 the 4th device has the index 3.

To access the second slave on the second master you have to run the application with

./bin/app_demo_master_object_dictionary -m 1 -n 2

Like the devices the index of the available masters start at 0.