Delta RMC151 - Manual (Page 908)

RMC70/150 and RMCTools User Manual
RMCTools, this will automatically be done for you.
This does not apply if the parameter is being changed with a command, such as with the
Offset Position (47) command.
Tag Names
Tag names for axis status and parameter registers use the format _Axis[x].reg, where x
specifies the axis number and reg is the tag name for that register. For example,
_Axis[2].ActPos is the Actual Position of Axis 2.
If there is no number in the brackets, such as _Axis[].ActPos, the axis is the current axis
for the current task. See the Tasks topic for more details.
9.2.2.2. Feedback
9.2.2.2.1. Position Scale
Type: Axis Parameter Register
RMC70 Address: %MDn.0, where n = 12 + the axis number
RMC150 Address: %MDn.0, where n = 24 + the axis number
System Tag: _Axis[n].PosScale, where n is the axis number
How to Find: Axes Parameters Pane, Setup tab: Primary Control Setup
Data Type: REAL
Units: pu/Counts
Range: any
Default Value: 1
Description
This parameter is used together with the Position Offset parameter to convert the
transducer feedback Counts to an Actual Position. The Position Scale specifies how many
position units equal one transducer feedback Count.
To reverse the direction of the feedback, use a negative Position Scale.
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.
Setting the Scale
In general, to set the scale, determine how many Counts correspond to one position unit
(inches, meters, etc., as desired). The Position Scale is the inverse of that number. For
specific details on converting counts to position units refer to the appropriate topic:
• MDT Scaling
• SSI Scaling
• Quadrature Scaling
• Analog Position Scaling
• Resolver Scaling
Why bother?
It is important to specify the measurement units to be used for each axes. Setting the
Scale converts the information from the transducer into meaningful measurement units.
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