Fault/Idle Action Tab - 1794-VHSC

Use this tab to configure counters and their safe state values for a module. On this tab you can configure inputs and outputs and:
  • force a counter to reset and begin counting
  • force a counter to use the preset value specified on the Output Counter tab
  • specify a reference point (or count) from which the module begins counting
  • control outputs
  • allow the module to hold its last state
Parameters
Communication Fault and Program Mode Behavior
Select the way in which you want the adapter to respond when a communication fault occurs with this module, or the controller is placed in Program mode. You have the following choices:
  • Reset - Resets the module outputs to zero. The VHSC does not distinguish between Reset and Fault/Idle. The Reset state is just another set of Fault/Idle settings. When you click the Reset button, the Safe State settings for Reset are programmed into the Fault/Idle settings, and the next time you return to this tab, the settings are correct for Reset Fault/Idle action, but with Safe State checked.
  • Safe State - This feature allows you to provide a safe state values
    You have full access to the Fault/Idle tab entries to define a safe state for this application.
Counter Reset
When one of these members are set to 1, the associated counter is reset to zero and begins counting. The module can also be reset with the Gate Interval member of the configuration data type. Outputs are adjusted according to the window compare values.
Counter Preset
In encoder or counter modes, this member represents a reference point (or count) from which the module begins counting. The transition of this bit from a 0 to a 1 sets the counter to the value specified by the Preset words. The module can count either up or down from the preset value. Values can range from 0 to 16,777,215. Outputs are adjusted according to the window compare values.
Value Reset
A 0 to 1 transition of this member clears the stored/accumulated count data in the Stored Data members of the input data type.
PWM Hold Last State
This feature is selectable when Pulse Width Modulation is chosen for the type of input counter from the Counter Configuration tab. When this checkbox is checked, a value of 9501 (95.01%) is entered in the PWM Safe State Value and SS Percent fields forcing PWM safe state for that channel.
PWM Safe State Value
The range of PWM values is: 0 £ value £ 9500. Entering a value of 9501 (95.01%) signals the module to a Hold Last State condition for the associated channel. When the module is programmed for a PWM configuration, the time base is enabled, the counter for the respective channel, its gate interval, its rollover, and its First On and First Off value are used. Ties can be used to direct the PWM signal to any or all of the outputs.
PWM SS Percent
This feature is for display only use and shows Channel 0 and Channel 1 Pulse Width Modulation Safe State Values expressed in percent.
Outputs
Outputs may be forced on or off independent of count or frequency value. Outputs are forced on when you enable the Output Enable feature discussed below or you can enable the outputs through the OutEnable member of the AB:1794_VHSC:O:0 module - defined data type.
Force Output
When this bit is set to 1, outputs are turned on if any of the Output Enable is 1. When set to 0, outputs can be controlled by a compare match, or as directed by the Pulse Width Modulation (PWM) settings.
Output Enable
When this feature is set to 1, outputs are permitted to be turned on from either a force on, a compare match, or as directed by the PWM settings. When Output Enable equals zero, the module turns the associated output OFF.
Local Control
This module receives electrical power in two ways:
  • Over the backplane
  • from the terminal block
If Local Control is set to 0, then the module will reset if either power is lost. If Local Control is set to 1, then the module will continue operating with power from the terminal block; if Output Enable is set to 1, the module will continue setting outputs as well. If backplane power is then restored, a communications fault will occur, indicating that the Safe State values must be set correctly, or the outputs may be switched off.
When this bit is set to 1 and FlexBus power is removed (i.e., if the module detects a FlexBus reset signal), the outputs remain under counter control. Use caution when using this feature, as the module is no longer communicating with the controller when FlexBus power is off.
When Local Control is set to 0 and FlexBus power is removed, the module clears its associated Output Enable bit.
You must also set this bit appropriately in the Safe State word to achieve predictable operation, since a communications fault occurs once adapter power is lost.
OK
Click this button to accept your edits on all tabs and close the dialog.
Cancel
Click this button to delete your edits on any tab and close the dialog.
Apply
Click this button to make your edits effective on any tab and continue editing.
If:
  • you are online in Program, Remote Program or Remote Run mode and,
  • this controller is the owner controller and,
  • you have changed the module’s configuration in the software,
when you click the Apply or the OK button, the information is automatically sent to the controller. The controller tries to send the information to the module (if the connection to the module is not inhibited). If you don’t click the Apply or OK button, your changes are not sent to the controller.
Tip:
The connection to a FLEX I/O module using Rack communication cannot be inhibited. The ‘Inhibit’ check box on the Connection tab is disabled in this case.
Help
Click this button for assistance with this tab.
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