Counts

Type:	Axis Status Register
RMC70 Address:	Fn:11, where n = 8 + the axis number
RMC150 Address:	Fn:11, where n = 8 + the axis number
System Tag:	_Axis[n].Counts, where n is the axis number
How to Find:	Axes Status Registers Pane, All tab: Feedback
Data Type:	REAL
Units:	counts

Description

Counts are the feedback from the transducer. The Counts register is used to calculate the Actual Position for axes with MDT, SSI, or Quadrature transducers. Axes with voltage or current input do not have a Counts register. They have a Voltage or Current register.

The Counts are derived as follows:

MDT Inputs:

The Counts are the Raw Counts.

SSI Inputs:

The Counts are the Raw Counts with the Count Offset applied. Also, for absolute rotary axes, the Counts are in the opposite direction if the Position Unwind is negative.

The Counts formula for positive Position Unwind is:

Counts = (RawCounts + CountOffset) MOD MaxCounts

For negative Position Unwind, the Counts formula is

Counts = ([MaxCounts-1] - RawCounts + CountOffset) MOD MaxCounts

Quadrature Inputs:

The Counts register accumulates encoder counts. The direction of the accumulation depends on the sign of the Position Scale or Position Unwind parameter. This value is adjusted when the axis is homed or when an Offset Position (47), Set Target Position (48), or Set Actual Position (49) command is issued. This value will wrap between -2,147,483,648 and +2,147,483,647. However, Delta recommends that the this value never exceed 24 bits (16,777,216). See the Exceeding 24 Bits section of the Feedback Resolution topic for details.

Resolver Inputs:

The Counts are the Raw Counts with the Count Offset applied. Also, for absolute rotary axes, the Counts are in the opposite direction if the Position Unwind is negative.

The Counts formula for positive Position Unwind is:

Counts = (RawCounts + CountOffset) MOD MaxCounts

For negative Position Unwind, the Counts formula is

Counts = ([MaxCounts-1] - RawCounts + CountOffset) MOD MaxCounts

See the Exceeding 24 Bits section of the Feedback Resolution topic for details on the 24-bit limitation of the Counts register.