Delta MMC120 - Manual (Page 111)

111
Click here for MDT SCALE Calculation examples
NOTE: When the SCALE parameter is changed, the EXTEND LIMIT , RETRACT
LIMIT , and OFFSET must also be changed.
NOTE:You should never set the SCALE below 16383. If it does go below that value,
then use the Prescale Divisor bits in the CONFIGURATION WORD . As you
can see from the ACTUAL POSITION calculation above, this will affect the
scaling, but will reduce round-off errors.
SCALE Calculation Examples
Example 1
For a system using a magnetostrictive transducer with a calibration number of
9.1392 µ s per inch, a position unit of 0.001 inch, and 1 recirculation, the SCALE
will be:
scale = 1000( Position Units Per Inch) x 32768= 29878.62
9.1392( µ s/in) x 120MHz x 1 (Recirculations)
SCALE = 29879
Example 2
For a system using a magnetostrictive transducer with a calibration number of
9.0110 µ s per inch, a position unit of 0.1 millimeter, and 1 recirculation, the
SCALE will be:
scale = 254(Position Units Per Inch) x 32768 = 7697.14
9.0110( µ s/in) x 120MHz x 1 (Recirculations)
Since the scale is less than 16383.5, use the Prescale Divisor bits in the
CONFIGURATION WORD to divide the transducer counts by 4. Then multiply
the scale by 4 to obtain:
SCALE = 7697.14 x 4 = 30789
Example 3
For a system using a magnetostrictive transducer with a calibration number of
8.9772 µ s per inch, a position unit of 0.001 inch, and 8 recirculations, the SCALE
will be:
scale = 1000(Position Units Per Inch) x 32768 = 3802.22
8.9772( µ s/in) x 120MHz x 8 (Recirculations)