Introduction

XTS transport layer (a station based approach)

XTS transport layer projects

[XTS_TR07] - intended for use

[DOCUMENTATION] - flow charts

• functional basics of CA Group

• use of XTS_Utility lib

• introduction to station based approach

• configurable station placement

• station acts as sender

• configurable station design with basic transport logic

• configurable station design with variable transport logic

    individual targeting of mover to Station
    grouping of stations for parallel or serial work flow of extern process
  

• function blocks with ctrl/state structs:

    cyclic check on change of command enumeration  
    state struct enumeration with offsets for progress  
  

• This project collection is intended to convey the idea of a stand alone XTS transport layer to use in heterogen environments / applications. The main idea is that for every process a corresponding position on the xts exists.

• In order to reduce the amount of repetetive work when implementing a XTS into a machine, this project collection may help to put a transport layer in place

• A transport layer shall have an interface for guiding a mover through a process station

• A transport layer shall have an interface to manipulate a mover within a station or for a certain task

• A transport layer shall have an interface for setting-up or clearing the CollisionAvoidance Group

The following explanations and descriptions shall help to set up a transportation layer that suits your requirements

Getting Started

• FORMATTING: my OCD my fomatting, allspaces no tabs, indent 2

• please read the code and datatypes, in most places I left comments

• ... MAIN(PRG) and GVL_XTS are good places to start

• projects are numbered with rising level of complexity

• choose wisely

• TR_00:

  • TwinCAT project with XPU simulation and NC Axis

• TR_01:

  • fb_CaGroup

    • handles Collision Avoidance Group
    • ClearGroup
    • BuildGroup
    • EnableGroup

  • fb_Mover

    • MC2 function blocks
    • CA function blocks

  • GROUP(PRG), MOVER(PRG)

    • simple examples, replaced later they will be

• TR_02:

  • fb_Xpu

    • cyclic checks to ProcessingUnit
    • Mover 1 detection
    • access to local instance of Tc3_XTS_Utility function blocks;
    • OTCID Initialization and checks added

• TR_03:

  • fb_TransportUnit

    • interface to extern control

    • interface to fb_Xpu

    • interface to fb_CaGroup

    • Interface to fb_Mover

    • Operation Modes (change of mode is checked):

        _eCmd                         := _Ctrl.Cmd;
      
        // check for command change
        // get state for cmd
        IF (_eCmd <> _eCmdOld)
        THEN
          _eState                     := Cmd(_eCmd);
          _eCmdOld                    := _eCmd;
        END_IF
      
        //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
      
        {attribute 'strict'}
        {attribute 'to_string'}
        TYPE E_XTS_TRANSPORT_CTRL :
        (
          CMD_NULL,
          CMD_INIT                  := 10,  // Xpu, Group, Mover initialization: clear errors, clear group, check Xpu data, check mover detection
          CMD_IDLE,
      
          CMD_MOVER_ENABLE          := 20,  // all mover are enabled, checked for ControlLoopClosed
          CMD_MOVER_DISABLE,                // all mover are disabled, no axis in CaGroup: no error, any axis in CaGroup: group error
      
          CMD_GROUP_CLEAR           := 30,  // halt all movers, clear errors, remove all movers from group, clear group
          CMD_GROUP_BUILD,                  // add all movers to group
          CMD_GROUP_ENABLE,                 // group with movers is enabled
      
          CMD_TRANSPORT_START       := 40,  // move all mover[i] to start position
          CMD_TRANSPORT_RESTART             // move all mover[i] to LastPosition[i]
      
        )UINT;
        END_TYPE
      

• TR_06:

• Introduction of fb_Station: mover is handled by handshakes, targets can be set during operations

• Stations are defined in ST_STATION_PARAMETER

  • Station Parameter description see below (Who's who)

• fb_Station

  • interface to extern control; infeed from linked list entry, process handshake, sending mover to target and adding tail at linked list of target station

  • command and state interface for access to station workflow

    • ST_STATION_CTRL:

      • eCmd : E_STATION_CTRL;
      • nMask : BYTE; // nest mask for sending mover to next station
      • nTargetStation : USINT; // where to next? [index of station in global array]
      • rOffset : REAL; // optional offset for mover in target station when leaving sending station;
        // use case: position correction of workpiece on wpc by vision

    • ST_STATION_STATE :

      • eState : E_STATION_STATE;
      • nMask : BYTE; // current nest mask of mover in station
      • nMoverId : USINT; // mover ID in station
      • nQueue : USINT; // queue count for station

• I_Station_LinkedList:

  • Linked list implementation for sending mover to target, every station has its own list
    • AddTailValue:
      • sending station adds mover at tail of target station
    • GetHead:
      • station gets mover ID and optional data from top of its list
    • Count:
      • how many mover were entered into list

• I_XtsTransport_Mover:

  • Mover interface for use in fb_Station
  • CA methods used for positioning and sending of mover

• TR_07:

• message handling: Verbose, Info, Warn, Error

• e_Device: first category where message was set

• e_SubDevice: second category where message was set

• iError: Error message from function block or MoverId for Verbose msg

• .

• MessageData(PRG)

  • automated write to file, new file for each day

• GVL_MSG

  • namespace for everything message related

Build and Test

• each project is complete with XPU in simulation mode

Members

• ExternControl

  • missing in this repo

• XTSTransport PLC

• designed for use with extern cyclic or non cyclic flow control

• station based approach with individual targeting of mover

• handshake in station with extern process flow
  (ST_STATION_CTRL / ST_STATION_STATE)

• individual cyclic mover interface with given set of movement functionalities
  (ST_MOVER_CTRL / ST_MOVER_STATE)

XtsTransport - Who's who?

XTS/_Visualizations:

  XTS_TRANSPORT: main control of transport
  - use ST_XTS_TRANSPORT_CTRL / ST_XTS_TRANSPORT_STATE 
    (GVL_XTS.XtsTransportCtrl / GVL_XTS.XtsTransportState)
  - StartUp sequence for CMD_TRANSPORT_START: (wait for each PROGRESS_DONE)
	- CMD_INIT or CMD_NULL
	- CMD_GROUP_CLEAR
	- CMD_GROUP_BUILD
	- CMD_GROUP_ENABLE: (mcGroupStateNotReady)
	- CMD_MOVER_ENABLE: (mcGroupStateStandby or mcGroupStateMoving)
	- CMD_TRANSPORT_START: (now handshake with ST_STATION_CTRL / ST_STATION_STATE can start)
	
  STATION_VISU:  handshake for stations
	- regular handshake sequence as buttons
	
  MOVER_VISU:    Access to cyclic mover interfaces.
	- use ST_MOVER_CTRL / ST_MOVER_STATE (GVL_XTS.MoverCtrl / GVL_XTS.MoverState)

MAIN:

  you better call MAIN(), cyclic calls to everyone

XTS/XTS_Parameter:

constants are always upper case
constants from XTS_Utility lib are mapped onto shorter names here
use XTS_Utility lib 
TcIoXtsEnvironmentParameterList 
for setting up your system
this project relys on those parameters to be correct

XTS/GVL_XTS:

AXIS_REF for mover
global instances of function blocks and Ctrl/State structs

XTS/XtsTransportUnit:

fb_TransportUnit
xts and mover are set to defined state
interface to extern control for mode selection
current state of example is that command CMD_TRANSPORT_START 
is sending all mover to startup position 
and adds all mover to queue of startup station 
--> now handshake of stations can start

XTS/CaGroup:

fb_CaGroup
handles Collision Avoidance state
AddAll()
RemoveAll()
Reset()
Enable()
Disable()

I_XtsTransport_Group

XTS/Mover:

fb_Mover cyclic interface 

- for extern usage (ST_MOVER_CTRL / ST_MOVER_STATE)
- methods are writing LastPosition and Last Gap 
- for each mover on motion execute
- Interface pointer for use within fb_Station and fb_TransportUnit.
- see E_MOVER_CTRL for available functionalities

XTS/XtsStation:

rPosStop: is added to WaitPos, beware when using negative offsets (avoiding collision, no movement, no error)

fb_Station cyclic interface 
- for extern usage (ST_STATION_CTRL / ST_STATION_STATE)
- handshake for mover infeed, process (nests), outfeed
- static offset datafield for every Mover in every station with every nest
- additional process offset by LinkedList entry
- Interface to LinkedList use for adding mover to target station queue 
- after mover has left the station

Planning requirements for use of fb_Station:

- Put the Modulo turn anywhere, 
  BUT NOT within WaitPos, StopPos, ReleaseDistance of a station. 
  The code does not support crossing the modulo turn within a station.

- The Use of LinkedList methods (AddTail, GetHead) 
  requires thought about when the mover is entered into the target station.
  
	- 1. parallel stations for a process:
		EXAMPLE:
		P1 uses XTS_STN[1] to XTS_STN[4] 
		--> The ReleaseDistance of STN[4] shall be shortest, 
			all other stations follow accordingly.
		EXAMPLE:
		condition: STN[4].WaitPos > STN[3].WaitPos
		for n := 3 to 1
			STN[n].ReleaseDistance := 
			  STN[4].WaitPos 
			- STN[n].WaitPos 
			+ STN[4].StopPos[furthest pos out] 
			+ STN[4].ReleaseDistance
									 
	- 2. using stations sparsely:
		in this case it is easiest to always handshake 
		the stations and use the forwarding command if 
		a station shall be skipped: STATION_MOVER_SEND.
			
	- 3. deactivating stations:
		make sure the queue is empty before deactivating, 
		since the waiting mover will hold up all the others
		in case of required deactivation while movers are in the queue:
		- handshake mover with 
		  E_STATION_CTRL.STATION_MOVER_SEND to new target station
		- do not send any new mover to the station in question
		- disable station
		- preceeding stations continue workflow 
		  with changed ST_STATION_CTRL.nTargetStation

know thyself

- all coordinates are modulo values, from station to station only forward, 
  within station limits backward movement by use of negative nest offset 
  or use of ST_MOVER_CTRL. 
  IF move backwards you have to make sure that there is room for it 
  --> distance between PosWait and PosStop

- station is defined by PosWait, PosStop[], and ReleaseDistance

TYPE ST_STATION_PARAMETER :
STRUCT
  sText             : STRING(80); // only description
  // start of station, a sending station is using this value to send mover to
  rPosWait          : REAL;       

  // distance from Mover.ActPos has to travel in order 
  // for station to go back to checking list entries
  rReleaseDistance  : REAL;       

  rGap              : REAL;
  rVelo             : REAL;
  rAccDec           : REAL;
  rJerk             : REAL;

  // how many nests (stop positions) mover has to stop at (1 = default)
  nConfiguredStopCount  : USINT := 1; // 1-8 --> NestMask = BYTE

  // mover stop position in station, relative to rPosWait!!
  rPosStop          : ARRAY[1..8] OF LREAL;
END_STRUCT
END_TYPE

XTS/XPU

  fb_Xpu:
    - one Track, one Part, (InfoServer not yet)
    - cyclic plausibility checks to ProcessingUnit and MotorModules
	- Mover 1 detection after Init
    - connects local function blocks to XTS_Utility lib
    - collects motor module info data

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