Direct Start with XPM_DST - LS Electric XGB PLC from AutomationDirect

the ls electric xgb has multiple ways to initiate motion complex moves and sequential moves will use the position data table in the xgp software to Define these moves and then use various function blocks in the xg5000 programming software to call them up however the xgb also supports a direct start function which allows us to define the move directly from the logic in xg5000 without referencing the position data table the xpm DST function block can be useful for programming numerous moves with a single function block as the direct start parameters may be altered between function block execution this allows nearly unlimited simple moves without using up a lot of memory and processing power however they do have some limitations for example the direct start function will not work for multi-axis interpolated moves or multi-move sequences these will require the use of the position data table for this example I have the XM motion training project open this file is available to download from the ex GB interactive guide at automationdirect.com it is designed to allow us to simulate a 3axis motion system without having to have any physical Hardware attached to the CPU we have already configured our axes in the X GPM software in a different help topic please refer to it and the product documentation for more information on access configuration prior to attempting any motion we also have powered up the Axis in our logic and turn the servos on which are figurative in this example most of the motion profile files in this project are interpolations using indirect start function blocks however we do have a direct start function block for each of the axes if we go to the axis one motion program and go to line 90 we see that we have an xpm DST function block currently we don't have enough columns to see the entire line of code so let's add a few columns to our programming environment you can go to view change columns increase columns or we can go to the icon of a series of cells with arrows pointing outward now if we look at line 90 we see that if we are commanding an absolute move and the program is in absolute mode and access one is ready we will request a direct start this direct start will command base zero which is our main PLC base slot one which is the onboard pulse motion controller and axis one which is the x-axis in our system let's move to a target of 1,000 pulses at a speed of 500 pulses per second our dwell time will be zero when we get to the end of the move and we aren't using the mcode function for this move our control value is currently zero which corresponds to a position move we could set this to one for a speed move which is a velocity based move that requires the use of the xgm STP function block to stop motion this function block is covered in another help topic we could also set this value to two for a feed move which is an incremental move where the sign of the target position determines the direction of rotation please refer to the product documentation and help files for more details on each our absolute or incremental bit is showing zero so this will be an absolute move if this was a one our move would be an incremental move made relative to the axis's current position finally we are selecting zero for our Xcel and D cell if we leave monitor mode and double click on the top cell of the function block it will open the function /function block popup window if we click on the help option for this fun function block we see that the Excel and D Cel selection being set to zero refers to using preset one for Xcel and D Cel times for this move these presets are configured in the basic parameters for this access in the xgp software we cover setting these parameters in a different help Topic in our case Xcel Time 1 and D Cel Time 1 are both set to 500 milliseconds let's trigger our move and watch it execute in the trend monitoring tab first let's go out of monitoring mode so we can avoid filling our Trend with empty data we will then go to monitor Trend monitoring unselect view bit graph and display XY graph and add pause one Cur pause to our Trend graph this is a system flag variable that displays the current position of axis one we will leave these sample setting values at the defaults and click okay if we were still in monitoring ing mode the trend would begin to fill with empty data so it is important we left monitor mode prior to adding the variable to the trend if we go back to the axis one motion program line 90 we can go back into monitor mode make the axis One command. Direction absolute move bit true and then observe the motion with the trend monitoring we see the exposition go to 1,000 and hold there if we go back to the direct start function block and change the target back to zero and the speed to 100 we can then make the command bit true again and watch the move with our Trend monitoring we see the axess move back to zero and it happens much slower since we altered the velocity of the move the direct start function block is limited but it is a very powerful and simple way to perform basic single axis motion with the ls electric xgb plc