Spindle and Traverse Digital to Analog (D to A)

D to A value is a measure of speed with reference to the drive. Value is in binary and indicates what the board is outputting to the computer. Higher numbers indicate higher output voltage. The traverse D to A value should fluctuate above and below the spindle value, indicating a switch from upper to lower ratio.

The D to A numbers are 12 bit so the range of these numbers is between 0 and 4095. A value of 2048 is zero speed (mid point). Numbers greater than 2048 are forward speeds with 2048+1500 (3548) being full rpm forward, and 2048-1500 (548) being full reverse rpm. The numbers (ex: 3548 and 548) are approximate because certain factors can change the values that the computer sends out. For example, the computer is always monitoring the rpm of the spindle. If there is an increase in load on the spindle (such as exists with constant line tension and increasing coil diameter)  the computer will see a drop in the number of degrees of spindle displacement in a given time interval and will respond by increasing the D/A value.  

Indicators of Problems

  • Excessively high or low values could indicate an out of tune condition or bearing failure.
  • Spindle value should stay relatively constant. Traverse should fluctuate above and below spindle value.
  • Numbers should increase at higher speed settings.