TestWare-SX Cyclic Command

A cyclic command process produces a command signal that controls a servovalve or servomotor. This process should be sequenced in series with other command processes.

How it works

A cyclic command creates a waveform by assembling two single segments and repeating them continuously or for a predefined number of cycles. One cycle works like two monotonic commands. Three types of waveforms can be created. Both relative and absolute end levels are supported.

Haversine

Ramp or Triangle

Step or Square wave

More Information

The Cyclic Command Design window names the process and sequences it in a test template.

The Cyclic Command Parameters window defines the characteristics of the waveform.


Cyclic Command Design Window

This window specifies how the process starts and stops. The information in this window is saved with the test template.

Using the window

Use this window to assign a process location in a test template for a cyclic process.

1	Name the process with the Label entry field.

2	Select a Start Trigger to sequence the process. This process should be sequenced in series with another command process.

3	Select an End Trigger to stop the process. Use the default nonetrigger if you want the process to complete without interruption.

4	Select a Control Channel for the process.

More Information

You can find detailed information about this process in Chapter 6 of the 790.10 TestWare-SX Application Manual.

Go to How it works for an overview of the process.

After you complete this window, you can double-click the name of this process in the Edit Template window to display the Cyclic Command Parameters window. This allows you to assign parameters to the default procedure.


Cyclic Command Parameters
Cyclic Command Parameters Window

You must establish a cyclic process with the Cyclic Command Design window before you can use this window. Use this window to define the specific characteristics of the cyclic waveform. The information in this window is saved with the test procedure.

Segment Shape

Lists the segment shapes you can select and whether the end levels are relative or absolute.

Haversine

Ramp (triangle)

Step (square wave)

Compensator

Selects Phase/Amplitude Control (PAC), Peak/Valley, or none as the compensation method.

Rate Type

Lists the types of expressions you can select to define a cycle. The rate type allows you to specify the units you prefer to define a cyclic waveform. The types of expressions are:

Frequency

Time

Rate

Frequency, Time, or Rate

Specifies the cyclic command value. The label and type of units depend on the selected Rate Type above.

Repeats

You can repeat cycles or segments. Two segments create one cycle. Repeating a full cycle starts at level 1 and ends at end level 1. Repeating a segment can end at end level 1 or end level 2. Entering 0 repeats causes the waveform to cycle continuously.

Control Channels

Displays a list of the control channels selected in the Design window.

Control Mode

Selects the control mode for the cyclic command. Pressing the list icon lists the control modes defined with the Controller Definition program.

End level

Specifies the amplitude of the cycle (the difference between End level 1 and End level 2). The cyclic command goes to End level 1 first.

Phase Lag

Specifies how much the cyclic command of the selected control channel leads or lags another control channel. Press the list icon of the right entry field to select the phase units (degrees or radians). Type the amount of phase into the left entry field. A positive value lags the reference control channel and a negative value leads the reference control channel.

Using the window

1	Select a control channel.

2	Complete the control channel portion of the window to define cycle parameters that are unique for each control channel.

Select a control mode, end level units, and the phase units. Enter the two end levels and (if more than one control channel is listed) enter the phase value.

3	The upper portion of the window defines the cycle parameters that are common for each of the listed control channels.

Select a segment shape, rate type, rate type units, and the type of repeats. Enter the rate type value and the number of repeats.

Compensators

Compensators adjust the servovalve command signal to ensure that the programmed command is achieved.

None allows the command to be issued without any additional processing. None must be used when tuning the system.

Peak/Valley compensation is always available. It ensures the programmed amplitude is achieved and the mean level is maintained.

PAC compensation is only available if it is selected when defining the control channel. PAC ensures the programmed amplitude is achieved and phase is maintained. PAC reduces the servoloop update rate.

Phase lag

The Phase Lag specification is available when the cyclic command is to be applied to more than one control channel. One control channel should have a 0í phase; this provides a reference for another control channel phase setting.

More Information

You can find detailed information about this process in Chapter 6 of the 790.10 TestWare-SX Application Manual.

Go to How it works for an overview of the process.