DRIVE

This field displays the drive output in millivolts. This field has a minimum value of 10,000, representing full negative drive of -10,000 mV and a maximum value of +10,000, representing a full positive drive of +10,000 mV. The value in this field is translated to the physical drive output using a 12-bit (4000-step) digital-to-analog converter (DAC), which will generate a ±10,000 mV output in steps of 5 mV. The internal drive calculations are done to 14-bit resolution. This additional resolution is used to dither the least significant bit of the output, giving additional resolution.

In many applications, the full ±10 V range is not used, and drive output beyond that range may even be unsafe. For this reason, the Limit Drive (L) command can be issued to limit the drive output range to be smaller than ±10 V.

Note: This field is unused on 12-bit analog channels or 16-bit analog channels that do not include channels 0 and 2. That is, on 16-bit analog modules, only channels 0 and 2 have drive associated with them. On auxiliary pressure/force channels, the drive is only affected by the Open Loop command; when controlling pressure/force, the position axis's drive is used.

Note: Software adjusts the null. There are no hardware nulling adjustments on the motion control module. Null drive will be near 0 volts.

Why Bother?

If the DRIVE tries to go below -10,000 or above 10,000, an overdrive condition has occurred.