Axis Homing - LS Electric XGB PLC from AutomationDirect

let's look at a motion application with the ls electric xgb PLC for this example we will be using a 3axis motion system which utilizes many components offered at automationdirect.com our system is built on a sure frame extruded aluminum base with casters it utilizes igus Dryland actuators and sure motion couplers from automation direct attached to LS electric gearboxes driven by l7p Servo drives and Motors these drives are controlled by whole Trin outputs from an xem dn32 HP 6axis motion controller for nearly any motion application the very first step will be establishing a repeatable home position the xgb PLC offers several ways to do this so let's dive into the Homing options we have the XM motion demo project file open in xg5000 and are connected with the XM CPU this file is available to download from the xgb interactive guide at automation Direct before we start working with the home function blocks in the xg5000 software we need to configure the access properties in xgp to execute the home functions that we want let's open xgp from the xg5000 programming interface by going to tools position control we can then open the XM motion Demo X GPM file we will connect with the controller in X GPM as well we will start with our access parameter data to view the data we go to the project window on the left side of the screen expand number one access data and double click on parameter this opens the new. parameter window and displays the axis parameters for all six axes in the controller we are using axis one for our x-axis axis 2 for our y- axis and axis 3 for our z-axis so these will be the three axes we will be concerned with configuring we have already covered the general configuration parameters in another video so we will just focus on the Homing parameters the key homing parameters have their own subsection we can scroll down until we see homing parameter in the left side of the window home position is the value that the access Position will be set to when a homing function is completed the home high speed will be the more commonly used homing speed and the home low speed will be used for two segment homing functions such as moving to the overt travel limit sensor and then finding the home sensor home Xcel and Dell times are the time and milliseconds it takes for the access to reach full speed or full stop during a home movement home dwell time is used when the motion system has a small amount of system lag or mechanical deadband at the end of any D cell function there may be a slight position drift even after pulses or motion of stop being commanded the home dwell time is used to allow the drivetrain to cease motion prior to home being completed home compensation ation is how many pulses the axis should move after it completes a homing function to position the axis for cycling homing restart time is how long the system will pause between the two segments in a two segment homing function home direction is the direction the motor should move for the initial homing search home method is where we can Define the type of homing function we wish to use there are seven different options each specific to a different application please review the product documentation and help files for timing charts and home method selection assistance in our example we will use the same settings for our three AES home Position will be zero home high speed and low speed are 150 and 50 pulses per second respectively home Xcel and Dell times will both be 200 milliseconds home dwell time compensation and restart time will all be zero for home direction we will move in the reverse Direction and our homing method will be method six this method will move the axis in the home Direction at the home high speed until the Homing switch is seen the axis will then reverse until the Homing switch is no longer seen and then will go forward in the home direction again at home low speed until it sees the switch again now that we have our home settings configured we can assign the signal type for the upper and lower limit signal which is LS nomenclature for the forward and reverse overt travel inputs as well as the home signal input we don't have overtravel switches in our application but we will set our home signal to be normally closed now that we have finished finished with the Homing parameter configuration we can use x GPM to write this information to our motion controller now let's look at our xg5000 project to initiate a home function we can use one of two function blocks the xpm FLT function block or the xpm org function block the xpm FLT function block simply sets the current position as the home position configured in X GPM for the axis so no axis movement will result the xpm org function block is used with the parameters we set in X GPM to initiate a move to a home or origin Point our project uses an xpm org for each of the axes let's look at the function block for axis one we maximize axis one motion program and double click on program we will scroll down and find our home function block resides on line 17 of the latter code the function block itself is very straightforward we will tell it which of the axes in the controller we are commanding by listing the base slot and axis number it is our main PLC so it is base Z and if we look in the io parameter screen we see that the EM motion controller is in slot one and we are homing access one in our project we are making this function block true whenever the home command is true and the axis is ready and there are no errors present and the axis is not busy let's watch our system execute its homing sequence since it is a three AIS system we will home all three axis simultaneously if we look in the interpolation routines program we can scroll down to line 38 of the program and find the Home axis comment here we see a function to home all three axes before we initiate any movement it is important to note that we have functions in our project to stop motion using an xpm STP instruction as well as resetting access errors with an xpm rst instruction we won't cover these functions here but it is important to have them before executing any motion please also note that these instructions are not a replacement for a hardwired emergency stop please refer to your risk assessment to determine the safety needs for your application let's turn on our servos and start the Homing function for all three axes we see that each axis independently Moves In Reverse at the home high speed finds the home switch backs off at the home low speed moves forward back on the switch at the home low speed and then waits for the next command we have now HED our three AIS system and are ready for some motion