Invert Output Polarity

Type:	Axis Parameter Register
RMC70 Address:	Fn:34/0, where n = 12 + the axis number
RMC150 Address:	Fn:34/0, where n = 24 + the axis number
System Tag:	_Axis[n].OutputBits.InvertOutPol , where n is the axis number
How to Find:	Axes Parameters Pane, Setup tab: Primary Control Setup
Data Type:	bit
Range:	Not Inverted (0), Inverted (1)
Default Value:	Not Inverted (0)

Description

The Invert Output Polarity parameter bit specifies the polarity of the Control Output.

For closed-loop motion control, it is imperative that the output polarity is correct. A positive Control Output must move the axis in the direction of increasing Actual Position. This register can be used to set this. If the Invert Output Polarity bit is cleared, the physical voltage on the Control Output or Drive will be of the same polarity as the Control Output. If the Invert Output Polarity bit is set, the Control Output pins of the RMC module will be the negative of the voltage of the Control Output.

Changing the Invert Output Polarity

Since this parameter affects motion, the axis must be disabled or in Direct Output before writing to this parameter. The Status Bits indicate the state of the axis.

Why Bother?

If you wire up the system and find out that a positive Control Output moves the axis in the negative direction, instead of rewiring the Control Output, you can just set this bit. This is often useful on motors, when it isn't always obvious which way it should be wired.