Delta RMC101 - Manual (Page 552)

RMC100 and RMCWin User Manual
6-8
6.1.6 Analog Transducer Scaling
Defining the Valid 16-bit Pressure/Force/Position/Velocity Range
For general scaling information, see the Scaling Overview topic.
Because the RMC uses 16-bit words for positions, pressures, forces, and speeds, these
quantities must all fit within a range of 65,536 position units. Because the units used are user
definable, this range does not limit most applications. See the section below on defining the units
themselves.
The definition of the range of 65,536 position, pressure, force, or speed units depends on the use
of the analog channel.
For pressure and force channels, the range is fixed to that of a signed 16-bit integer: 32768 to
32767.
For position or velocity axes, the Offset and Scale parameters define the range. If the Scale
parameter is negative, then the position range extends from the Offset value minus 65535 up to
the Offset value. If the Scale parameter is non-negative, then the position range extends from the
Offset value up to the Offset value plus 65535. The following chart summarizes this concept:
Scale Min. Position Max. Position
< 0 Offset - 65535 Offset
³ 0 Offset Offset + 65535
However, because the Offset is also used to convert transducer counts to position units, it cannot
be set independently. For velocity control axes or velocity reference axes, the absolute position is
typically not important, and the Offset can be set independently.
Translating to Pressure Units
For every scan the RMC makes, the Counts A status field is converted to a value for the Actual
Pressure status field. This conversion uses the Scale A and Offset A parameters plus the
Prescale Divisor bits of the Configuration word.
The following formula shows the conversion:
Translating to Force Units
For every scan the RMC makes, the Counts A and Counts B status fields are converted to the
Actual Force A and Actual Force B, which are used to calculate Actual Force. These conversions
use the Scale A, Scale B, Offset A, and Offset B parameters plus the Prescale Divisor bits of the
Configuration word.
The following three formulas show these conversions: