Delta RMC151 - Manual (Page 915)

9 Register Reference
Actual Acceleration = Acceleration Scale x ((Voltage or Current) + Acceleration
Offset)
Changing this Parameter
Because this parameter affects motion, the axis must be disabled or in Direct Output
before writing to this parameter. The Enabled and Direct Output Status Bits indicate these
states of the axis. When changing this parameter from RMCTools, the software will
automatically do this for you. This may cause a halt on the axis, which is expected.
9.2.2.2.10. Position Unwind
Type: Axis Parameter Register
RMC70 Address: %MDn.12, where n = 12 + the axis number
RMC150 Address: %MDn.12, where n = 24 + the axis number
System Tag: _Axis[n].PosUnwind, where n is the axis number
How to Find: Axes Parameters Pane, Setup tab: Primary Control Setup
Data Type: REAL
Units: pu
Range: not equal to zero
Default Value: 1000
Description
This parameter is used on rotary position axes together with the Count Unwind, Position
Offset and Count Offset parameters to convert the transducer feedback Counts to an
Actual Position.
The Position Unwind parameter defines the valid range of positions for the axis. When the
position units reach the end of the valid range, they will wrap around to the beginning of
the range. For example, consider an axis with a Position Unwind of 360. If the axis
rotates continuously, the position will go from 0 up to, but not including, 360. As it
reaches 360, it will "wrap" to 0 and keep going.
For absolute rotary axes, the Counts are in the opposite direction if the Position Unwind is
negative.
The Counts formula for a positive Position Unwind is:
Counts = (RawCounts + CountOffset) MOD MaxCounts
The Counts formula for a positive Negative Unwind is:
Counts = ([MaxCounts-1] - RawCounts + CountOffset) MOD MaxCounts
The Position Offset defines the value at which the position units begin.
Examples:
Position
Unwind
Position
Offset Position Range
360 0 0 to 360
360 -180 -180 to 180
360 60 60 to 420
Absolute Rotary axes also use the Count Offset parameter to move the zero point of the
Counts. The position range begins where the Counts are zero.
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