Steps to initialize the Single_w program for a new number of motors


to use the program to drive a translation device.


  1. Connect the Sin10 to the first input serial port on the DAX.
  2. The Sin10 is connected to the COM1 (#3F8) port of the computer by a serial connector cable.
  3. We assume that the DAX is properly connected to the Stepper motors.
  4. If you are executing the single_w program for the first time on a new machine, then you need to first run the RegSetup.exe program that has been provided along with the other files. It will install the device driver that is required for serial communication. Once the computer restarts, you can proceed with the next step.
  5. Execute the single_w program.
  6. The Single Diffractometer Control Program dialog box appears. Check Motors and Initialize motor settings option. Leave the other items two unchecked.



  1. The Motor Parameters dialog box appears.

·       The Motorport (Hex) list box should read ‘3F8’.

·       There are 4 Motor Connected check boxes. You can select 1 to 4 motors from left to right. In the illustration, 2 motors have been selected. The headers 2-Theta, Omega, Chi and Phi are meaningful for a four-circle diffractometer, but for arbitrary purposes can be considered as motors 1-4. All data in the Chi and Phi columns are meaningless when only 2 motors have been selected.

·       When using these motors to drive a translation device Steps/Degree should be interpreted as steps per unit length. You must calibrate this parameter.

·       You may find that a motor moves in the negative direction when you give it positive movement. The positive direction is arbitrary and is influenced by simple things like how the stepper motors were connected. Thus, if you want to change the direction of positive motion of a stepper motor, then change the state of the check box labeled “Change Motor Direction”.

·       Slew Velocity determines the speed at which the motor turns. You must decide for yourself what is a good speed. It is a function of all sorts of things, but you should choose a speed that produces low motor noise and is acceptable to the experiment.

·       Ramp Steps determine acceleration. A value of 15 means the motor will accelerate from 0 velocity to the assigned value of the Slew Velocity in 15 motor steps.

·       Jog Speeds refer to a manual controller and is not applicable right now, unless you attach a manual controller. Talk to me if you want to do this.

·       After setting the parameters, click on the Initialize button.



  1. While the motors are being initialized, you will see a warning to indicate that the motor positions will be reset to zero and whether you wish to continue. Click on Yes and proceed.



  1. Please wait while the motors get initialized. At this stage, if there is some problem, then contact us. Once the initialization is done, you will be asked to choose a parameter file name for storing the log file that keeps an account of the experiment. Choose a new directory and pick a file name. These are artifacts of the diffractometer code. Then click OK.

If problems will occur, it is likely that they will happen at this stage because the DAX units have to be properly initialized with the manufacture’s software. The motors drives should be labeled “A”, “B”, “C”, “D”,…. If you switched your units from two DAX to one, then a error may occur if you hooked up the unit that was initialized for “C” and “D” instead of “A” and “B”.





  1. If you have a translation device, then you can perform any desired operation under the Motors menu option. You will probably use ‘Drive To Angles…’ to move the motors. The word angles here should be interpreted as unit length translations. This unit is defined in the “Parameters…” menu, by Steps/Degree.
  2. The Status bar will display the current motor positions.
  3. The “Drive to Indices…” menu is meaningless for translation purposes.
  4. Reset Origin…” allows you to set the current motor positions to any other position. It is most commonly used to set the current motor positions to 0.
  5. Clicking on the Halt button will stop a motor that is in motion.
  6. Goto Zero” will drive the motors to the motor position that has been defined as the origin.