Delta RMC151 - Manual (Page 167)

3 Controller Features
3.7.2. Controlling Only Pressure or Force
This topic describes how to perform pressure/force control on a pressure-only or force-only
axis. Torque control is identical to pressure or single-input force control. For details on
position-pressure or position-force axes, see the Position-Pressure and Position-Force Control
topic.
Required Hardware
A pressure-only or force-only axis requires the following RMC hardware:
• One Control Output
• One or Two Analog Inputs
Two analog inputs are required only if you are using two pressure transducers for
differential force feedback.
Note: Any analog input will suffice. The RMC70 does not require the AP2 module for
pressure-only or force-only axes. The RMC150E does not require the pressure
option (indicated as RMC151) for pressure-only or force-only axes. These are only
required for dual-loop axes, such as position-pressure or position-force.
Pressure or Force feedback requires analog feedback transducers (voltage or current).
The input range from the transducer must fall within the RMC supported ranges of ±10V
or 4-20mA. For the best resolution, the feedback should use a large portion of the ±10V
or 4-20mA range.
Define the Axis
The first step for pressure/force control is to define the pressure/force axis. This means
assigning the physical inputs and analog Control Output to an axis in RMCTools.
1. Open the Axis Definitions dialog to define the axes.
2. In order to define the axes as you want them, you may need to first remove the
existing axes and add new axes. Or, you may be able to change an existing axis.
3. Whether you choose to change an existing axis or add a new axis, set the axis to the
following:
• Control Axis
• 1 Input
• Input Type: Pressure, Force (single-input), or Force (dual-input)
If you are using a single pressure transducer or load cell for the feedback,
choose Pressure or Force (single-input). If you are using two pressure
transducers for differential force feedback, choose Force (dual-input, diff.).
4. The Axis Definitions dialog will show you exactly which Control Output and analog
input(s) on the RMC will be used for the axis. You can change them if you wish.
5. Click OK on the Axis Definitions dialog. If you are online, these changes will be applied
to the controller. Make sure to update Flash and save your project.
Set Up the Pressure/Force Transducer Parameters
Make sure to set the following pressure/force parameters:
• Input Type: Choose Voltage or Current.
• Positive Pressure/Force Limit and Negative Pressure/Force Limit: These specify the
pressure/force in which the axis will be allowed to control in. If the Target
Pressure/Force exceeds these values, an error bit will be set and will halt the axis if
the AutoStops are set to do so.
Scale the Pressure/Force
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