Skip to content

Latest commit

 

History

History
165 lines (137 loc) · 3.68 KB

README.md

File metadata and controls

165 lines (137 loc) · 3.68 KB
Raw

EtherCatLinux

test of SOEM lib for Open EtherCAT Master

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

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 
	) 	

    //

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

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);

Accesing SDO and PDO

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

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
  • 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

multiple models

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

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)

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
  • Sync tasks ?

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