Controller States and Output Behavior

Introduction

The Magelis SCU HMI Controller defines output behavior in response to commands and system events in a way that allows for greater flexibility. An understanding of this behavior is necessary before discussing the commands and events that affect controller states. For example, typical controllers define only 2 options for output behavior in stop: fallback to default value or keep current value.

The possible output behaviors and the controller states to which they apply are:

omanaged by Application Program

okeep Current Values

oset All Outputs to Default

ohardware Initialization Values

osoftware Initialization Values

oOutput Forcing

ControllerLockout Feature

The ControllerLockout feature locks or unlocks the controller stop mode. A locked controller cannot be restarted until the controller is unlocked.

Attempts to restart a locked controller are ignored and a message appears.You can only initiate lockout once the controller is in STOPPED state. If the controller is in RUNNING state and you attempt to lockout, the attempt is ignored and a message appears.

The ControllerLockout is not managed through SoMachine, it is an internal boolean variable (ControllerLockout) of the HMI in Vijeo-Designer.

For more information on managing this variable, refer to the Vijeo-Designer Online Help.

Managed by Application Program

Your application program manages outputs normally. This applies in the RUNNING and RUNNING with External Error Detected states.

Keep Current Values

Select this option by choosing Keep current values in the Behavior for outputs in Stop drop-down menu of the PLC settings subtab of the Controller Editor. To access the Controller Editor, right-click on the controller in the device tree and select Edit Object.

Double-click the name representing the HMISCU device in the Devices windows to access the Controller Editor.

This output behavior applies in the STOPPED controller state. It also applies to CAN bus in the HALT controller state. Outputs are set to and maintained in their current state, although the details of the output behavior vary greatly depending on the setting of the Update I/O while in stop option and the actions commanded via configured fieldbusses.Refer to Controller States Description for more details on these variations.

Set All Outputs to Default

Select this option by choosing Set all outputs to default in the Behavior for outputs in Stop drop-down menu of the PLC settings subtab of the Controller Editor. To access the Controller Editor, right-click on the controller in the device tree and select Edit Object.

This output behavior applies when the application is going from RUN state to STOPPED state or if the application is going from RUN state to HALT state. It also applies to CAN bus in the HALT controller state. Outputs are set to and maintained in their current state, although the details of the output behavior vary greatly depending on the setting of the Update I/O while in stop option and the actions commanded via configured fieldbusses.Refer to Controller States Description for more details on these variations.

Hardware Initialization Values

This output state applies in the BOOTING, EMPTY (following power cycle with no boot application or after the detection of a system error), and INVALID_OS states.

In the initialization state, analog, transistor, and relay outputs assume the following values:

oFor an analog output: Z (high impedance)

oFor a fast transistor output: Z (high impedance)

oFor a regular transistor output: 0 Vdc

oFor a relay output: Open

Software Initialization Values

This output state applies when downloading or when resetting the application. It applies at the end of the download or at the end of a reset warm or cold.

The software Initialization Values are the initialization values of outputs images (%I, %Q, or variables mapped on %I or %Q).

By default, they are set to 0 but it is possible to map the I/O in a GVL and assign to the outputs a value different from 0.

Output Forcing

The controller allows you to force the state of selected outputs to a defined value for the purposes of system testing, commissioning, and maintenance.

You are only able to force the value of an output while your controller is connected to SoMachine.

To do so, use the Force values command in the Debug menu.

Output forcing overrides all other commands to an output irrespective of the task programming that is being executed (this does not apply to an output currently used by the embedded controller functions, such as HSC/PTO/PWM).

When you logout of SoMachine when output forcing has been defined, you are presented with the option to retain output forcing settings. If you select this option, the output forcing continues to control the state of the selected outputs until you download an application or use one of the Reset commands.

When the option Update I/O while in stop is checked (default state), the forced outputs keep the forcing value even when the logic controller is in STOP.

Output Forcing Considerations

The output you wish to force must be contained in a task that is currently being executed by the controller. Forcing outputs in unexecuted tasks, or in tasks whose execution is delayed either by priorities or events will have no effect on the output. However, once the task that had been delayed is executed, the forcing will take effect at that time.

Depending on task execution, the forcing could impact your application in ways that may not be obvious to you. For example, an event task could turn on an output. Later, you may attempt to turn off that output but the event is not being triggered at the time. This would have the effect of the forcing being apparently ignored. Further, at a later time, the event could trigger the task at which point the forcing would take effect.