Delta RMC151 - Manual (Page 1010)

RMC70/150 and RMCTools User Manual
9.2.2.6.11. Unidirectional Mode
Type: Axis Parameter Register
RMC70 Address: %MDn.60/12-14, where n = 12+ the axis number
RMC150 Address: %MDn.60/12-14, where n = 24+ the axis number
System Tag: _Axis[n].PriControlBits.UniMode, where n is the axis number
How to Find: Axes Parameters Pane, All tab: Output
Data Type: Bits - see Format Details below
Range: None (0), Positive (1), Negative (2), Automatic (3)
Default Value: None (0)
Description
Unidirectional Mode, also known as Absolute Mode, is specifically designed for systems
that require a unipolar control signal. Some common cases are:
• Two Hydraulic Valves
Some hydraulic systems have two valves, one for direction control, the other for flow
control. Unidirectional mode is for controlling the flow valve. The directional valve
must be controlled by other means, but Unidirectional Mode does provide for easy
switching of the control direction based on the directional valve setting.
• Unidirectional Belt
A belt that must always move in the same direction.
Unidirectional Mode will prevent the Control Output from going negative even if the Actual
overshoots the Target. When this occurs, the Control Output will be truncated at the
Output Bias, and the Integral Term will not wind up. How the direction of control is
determined is described below.
Unidirectional Mode applies only to closed-loop position, velocity, pressure, and force
control. It does not affect open loop commands, but it does affect the Quick Move
commands. The open loop portion of the Quick Move is adjusted in the same way as a
closed loop move.
Unidirectional mode should not be used on torque mode systems.
Direction Determination
Unidirectional Mode requires that the RMC knows the desired direction of motion on the
axis. This is specified with the Unidirectional Mode axis parameter and/or the Set Control
Direction (96) command.
Using the Unidirectional Mode Parameter
The Unidirectional Mode axis parameter specifies how the direction of control is
determined:
• None (0)
Unidirectional Mode is disabled.
• Positive (1)
The control direction will be positive when the controller is started up or when
Unidirectional Mode is first enabled. It can however be overridden using the Set
Control Direction (96) command, as described below.
• Negative (2)
The control direction will be negative when the controller is started up or when
Unidirectional Mode is first enabled. It can however be overridden using the Set
Control Direction (96) command, as described below.
• Automatic (3)
The control direction is automatically set based on the current Target Velocity.
Specifically, when the axis is in closed-loop position or velocity control, the control
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