Delta RMC101 - Manual (Page 610)

RMC100 and RMCWin User Manual
6-66
Resolver Wiring
Resolver Specifications
Resolver Scaling
6.5.6 Resolver Scaling
Defining the Valid 16-bit Position Range
For general scaling information, see the Scaling Overview topic.
Because the RMC uses 16-bit positions, positions must all fit within a range of 65,536 position
units. Because position units are user definable, this range does not limit most applications. See
the section below on defining position units.
For resolver axes, the Coordinate Limit parameter is used with the Scale parameter to define the
position range. If the Scale parameter is positive, then the position range extends from the
Coordinate Limit value (which would normally be negative) up to the Coordinate Limit + 65535. If
the Scale parameter is negative, then the position range extends from the Coordinate Limit value
(which would normally be positive) down to the Coordinate Limit – 65535. The following chart
summarizes this concept:
Scale Min. Position Max. Position
³ 0 Coordinate Limit Coordinate Limit +
65535
< 0 Coordinate Limit –
65535 Offset
Translating to Position Units
Before the translation from counts to position units begins, the Count Offset is applied to the
counts. This means that the value of the Count Offset is subtracted from the Counts before they
are displayed or processed in any way. For a full discussion on the use of the Count Offset
setting, see Resolver Configuration.
The following formula summarizes the translation from transducer counts to Actual Position units:
As described above, the Count Offset configuration setting has already been subtracted from the
Counts field before using this formula. If the Actual Position overflows the valid 16-bit position
range due to excessive travel of the axis, the position will wrap around to the opposite extreme
shown in the table of the minimum and maximum positions above.
Notice that the Scale can hold values from -32768 to 32768, but 16-bit signed numbers are
limited to -32768 to 32767. Therefore, enter a scale of 32768 as 0; the RMC will interpret it as
32768.
Calculating the Scale and Count Offset
Follow these steps to calculate the Scale and Count Offset parameters:
1. Determine the Scale