Delta RMC151 - Manual (Page 1000)

RMC70/150 and RMCTools User Manual
Bits
This register contains the following parameters. The bits for each are given in the right-
hand column.
Parameter Tag Name Bit Number(s)
Pressure/Force Orientation PFOrientation 5-6
For details on the values that each bit represents, see the respective parameter topic.
9.2.2.6. Output
9.2.2.6.1. Deadband Tolerance
Type: Axis Parameter Register
RMC70 Address: %MDn.41, where n = 12 + the axis number
RMC150 Address: %MDn.41, where n = 24 + the axis number
System Tag: _Axis[n].DeadbandTolerance, where n is the axis number
How to Find: Axes Parameters Pane, All tab: Output
Data Type: REAL
Units: pu
Range: ≥ 0
Default Value: 0
Description
In closed-loop position control (Position PID or Position I-PD), the Deadband Tolerance
parameter works together with the Output Deadband to reduce "hunting" and ratio the
deadband for smoother motion. The Deadband Tolerance has no effect on control in open-
loop or velocity (Velocity PID or Velocity I-PD) control.
The Deadband Tolerance affects two areas:
• Anti-Hunting
When the target is stopped, and the Position Error is less than the Deadband
Tolerance or less than the position corresponding to one half of a transducer Raw
Count, then the Integral Output Term will only be allowed to wind down. In systems
with a deadband, this avoids ratcheting the axis back and forth around the deadband.
Notice that this works even if the Output Deadband is 0. If the Deadband Tolerance is
zero, this still works with the window defined by the position corresponding to one half
of a transducer Raw Count.
• Deadband Ratioing
The Deadband Tolerance specifies a Position Error window inside of which only a
fraction of the Output Deadband is applied. This minimizes chattering, which might
otherwise be caused by the Output Deadband. If the Position Error is greater than the
Deadband Tolerance, the Output Deadband is applied normally.
Deadband Ratioing works as shown in the graph below:
o If the Deadband Output is non-zero, the target velocity is zero, and the
absolute value of the Position Error is less than the Deadband Tolerance, only
a fraction of the Output Deadband, proportional to the Position Error, is
applied, as shown in the graph below.
o If the absolute value of the Position Error is greater than the Deadband
Tolerance, the full Output Deadband is applied, as shown in the graph below.
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