Toggling a LED with EL2809 and pysoem

[MarcelloDavis]

Hello,

I am new to EtherCAT and pysoem. I installed the library on a raspberry Pi and am able to detect the connected slave devices (EK1100 and EL2809). An LED is connected to the EL2809 on output 1. So my goal is to toggle the LED via the EL2809 using pysoem on the raspberry Pi.

The basic_example is already ready to use to toggle a LED using an EL1259. I tried using this example and changing just the devices' product codes and the names in the SlaveSet.

However I don't get the LED to light up. Moreover, I don't think that I am fully understanding what the script does in particular.

1) Do I need the el1259_setup() function? If so, why do I need it? And what am I supposed to change in the .sdo_write()-calls? I am familiar with the notation .sdo_write(sdo_index, sub_index, setting, Boolean) , but I couldn't figure out the use of the 0x8001 object and why to use struct.pack('B', 1). Also, later on we write a rx_map_obj with 16 entries: What are these for?

`slave = self._master.slaves[slave_pos]

    slave.sdo_write(0x8001, 2, struct.pack('B', 1))

    rx_map_obj = [0x1603,
                  0x1607,
                  0x160B,
                  0x160F,
                  0x1611,
                  0x1617,
                  0x161B,
                  0x161F,
                  0x1620,
                  0x1621,
                  0x1622,
                  0x1623,
                  0x1624,
                  0x1625,
                  0x1626,
                  0x1627]
    rx_map_obj_bytes = struct.pack(
        'Bx' + ''.join(['H' for i in range(len(rx_map_obj))]), len(rx_map_obj), *rx_map_obj)
    slave.sdo_write(0x1c12, 0, rx_map_obj_bytes, True)

    slave.dc_sync(1, 10000000)`

2) Do I toggle the LED via SDO or PDO? In the above mentioned example I found this code snippet, which suggests that I need PDOs:

` toggle = True try: while 1: if toggle: tmp[0] = 0x00 else: tmp[0] = 0x02 self._master.slaves[2].output = bytes(tmp)

            toggle ^= True

            time.sleep(1)

` But what are the tmp[0] = 0x00 and 0x02 supposed to mean?

Can someone please help me understanding this?

[bnjmnp]

Within .sdo_write(sdo_index, sub_index, setting, Boolean), the "setting" is supposed to be a list of bytes. In the basic_example slave.sdo_write(0x8001, 2, struct.pack('B', 1)) sets "Enable manual operation" for digital output 1 of the EL1259. Where struct.pack('B', 1) creates a list of bytes that is only 1 byte long, and the value of the byte is 1. Maybe the pysoems readthedocs can help you a little bit. The slave.sdo_write(0x1c12, 0, rx_map_obj_bytes, True) updates the PDO mapping, for the EL1259. It defines what lays behind self._master.slaves[2].output. If you are new to EtherCAT it might help, to first start with a GUI based EtherCAT master system.

[bnjmnp]

Hi @MarcelloDavis, did you had any success with this project? Are you still working on it?

[bnjmnp]

Closed due to inactivity of the OP. Please reopen the ticket if you need further help on this.