EtherCatLinux

test of SOEM lib for Open EtherCAT Master

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• EL2798 8xdigital ouput
• EK1100
• EL5152 : 2x incremental encoder interface
• EL1819 : 16xdigitalinput
• EL7342 : 2xDCmotors

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Notes of useful functions

    //Check actual slave state . blocking function
    // 0 = all salve
 	uint16 ecx_statecheck(
        ecx_contextt    *context,
		uint16  	    slave,
		uint16  	    reqstate,
		int  	        timeout 
	)

    ecx_readstate() 	

    // 0 = master
    // return Workcounter or EC_NOFRAME 
    int ecx_writestate(
        ecx_contextt *context,
		uint16  	 slave 
	) 	

    //

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Notes

• you can make EtherCAT slave groups

• a slave can be in only one group

• to exchange process data for given

ec_send_processdata_group(X);
ec_receive_processdata_group(X, EC_TIMEOUTRET);

• IOmap is the fatest mechanism for accessing slaves IO data. ec_slave struct keeps pointers to the

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Set an output int 16 value when memory alignement needs to be considered, arguments is:

• slave numer in ethercat network

void set_output_int16 (uint16 slave_no, uint8 module_index, int 16 value)
{
    uint8 *data_ptr;
    data_ptr = ec_slave[slave_no].outputs;
    data_ptr += module_index * 2;

    *data_ptr++ = (value >> 0) & 0xFF;
    *data_ptr++ = (value >> 8) & 0xFF;
}

//set_output_int16(EL4001_1,0,slave_EL4001_1.out1);

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Accesing SDO and PDO

• PDO is Process Data Objects
• multilpe ways a slave can communicate with the

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Theory about Ethercat

• Ethernet for Control Automation Technologie
• open technology under International standads
  • (IEC61158)
  • 61784
  • 61800
  • ISO 15745
• Ethercat frame ends witha 16-bit WorkingCounter (WKC)
• incremented by the slave
• it's DAISY-CHAINED
• low-jitter synchronization (<= 1us)
• Uses IEEE 802.3 Ethernet physical layer and standard Ethernet frames
• up to 65535 devices (16bits)
• you have duplex communication on ethernet
• you can have network redundancy
  • only if line breaks

Frame Structure

• 1 datagram per frame
• Data frame strcuture =
  • Header
  • Data
  • Working Counter
• The WKC (Working Counter) is number of interactions contained in agiven datagram
• WC is ++ by each target, if the WC return isn't the on expected = error;
• 14 bytes headers
• Ethernet Data
  • 2 Bytes Len + 01
  • 44*-1498 Byte
• FCS
  • 4 bytes

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• Ethernet data is composed :
• Datag. Header (10 Bytes)
  • CMD (8bit)
  • IDX (8bit)
  • Address (32 bits)
  • Len (11 bit) of data
  • R (2)
  • C (1) = Circulating dtagram ?
  • R (1)
  • M (1) = More ? datagrams
  • IRQ (16 bits)
• Data (max. 1486 Byte)
• WKC - 2bytes

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multiple models

• AutoIncrement (start-up ?)
• Fixed Addressing (once identified)
• BroadCast (for init all target)
• Logical (use the FMMU to map data)

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EtherCAT state machine

• init (0x01) only access to the DL-information registers

• PreOp (0x02) Mailbox communication on the application layer, but no process data com

• SafeOp (0x04) Mailbox com on the app layer process input data (in safeOp only inputs are available)

• Op (0x08) : PDA and Outputs are valid

• EtherCAT slave controller (ESC)

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EtherCat Command types

• 0 NOP
• 1 Auto Increament Read
• 2 Auto Incremeant Write
• 3 Auto Increment Read Write
• 4 CONFIGURED ADDRESS READ
• 5 CONFIGURED ADDRESS WRITE
• 6 CONFIGURED READ WRITE
• 7 BROADCAST READ
• 8 BROADCAT READ WRITE
• 9 Broadcast Read Write -10 Logical Memory Read -11 Logical Memory Write -12 Logical Memory Read Write -13 Auto Increment Read Multiple Write

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• Sync tasks ?

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Notes

• To enter state OP we need to send valid data to outputs.
• The etherCAT frame handling is split into ec_send_processdata and ec_receive_processdata