PROBLEM
Trying to create Three Variable Control (TVC) with Acceleration as the primary control mode results in the following error window (Figures 1 & 2):
Axial – Acceleration – ‘Active fdbk’ – ‘Acceleration’ dimension is invalid. The Active fdbk dimensioin must be ‘Length’ or ‘Angle’ on 3- Variable controller.
Figure 1 – Error Window
Figure 2 – 3-Variable Control (TVC) in Station Setup
ANSWER
You must create the 3-Variable Control (TVC) control mode with Displacement as the primary control mode first (Figure 1).
Figure 1 – TVC setup with using Displacement as the primary control mode
Adding Acceleration as an additional control mode in 3-Variable Control (TVC)
- Click on the Control Modes tab.
- In the Input Resources select the Station tab and then expand the list for the channel.
- You should see the signals for Displacement, Acceleration and Velocity. Select the Acceleration signal.
- Click the plus (+) button to add Acceleration as a control mode.
- You can do the same for Velocity if desired.
- In the main panel tree view you can re-order the mode by dragging them up or down if desired.
Figure 2 – Adding Acceleration as a primary control mode in 3-Variable Control (TVC)