Delta MMC120 - Manual (Page 44)

Motion Control Parameters MMC120 Linear Motion Control Module
44 Delta Computer Systems, Inc. 360/254-8688
When the axis is moving, the TARGET POSITION is updated each millisecond as it moves toward the
COMMAND POSITION. The value can be read by the Quantum Controller on every scan.
NOTE: When an axis is stopped, the TARGET POSITION should be the same as the COMMAND POSITION
unless an error or HALT has occurred.
TRANSDUCER COUNTS
TRANSDUCER COUNTS is the axis position read directly from the transducer counters with no scaling.
TRANSDUCER COUNTS can overflow the 16-bit value; status bit 6 is set when this happens.
ACTUAL SPEED
The ACTUAL SPEED is the calculated speed at which the axis is moving at any point in time. It is based on
changes in transducer counts, displayed in position units per second, and updated every millisecond.
DRIVE
DRIVE is the output to the actuator in millivolts. The 12 bit (4000 step) digital value output, -10000 (full
negative drive) to 10000 (full positive drive) will generate a ±10 volt output in steps of 0.005 volts. Note that
there are no pots to electronically null the output; this is done in software. Null drive will be near 0 volts. 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.