impulse-generator

Description

The impulse-generator block generates a sequence of timed impulses consisting of alternating working and sleeping phases. It can be started by a command sent from the command block, by an edge, by a logical level, or automatically after project initialization if its input is not connected to anything.

While running, the block provides separate outputs that indicate the working phase, the sleeping phase, and whether the generator is currently active. If the impulses parameter is 0, the generator keeps running until it receives the reset command from the command block. For a finite number of impulses, the generator also goes through the sleeping phase after every impulse and returns to the idle state only after the final sleeping phase ends.

Configuration parameters

Parameter name	Value
`input_edge`	Required parameter that defines the trigger condition for working modes that react to input events. Supported values: `rising`, `falling`, `both`, `true`, `false`, `null`, `none`. In practice, `rising`, `falling`, and `both` are used most often.
`impulses`	Required parameter that defines the number of impulses to generate. Allowed values are from 0 to 18446744073709551615. The value 0 means continuous operation without automatic stop.
`working_time`	Required parameter that defines the duration of the working phase of a single impulse in milliseconds. Allowed range: from 100 ms to 1209600000 ms (14 days).
`sleeping_time`	Required parameter that defines the duration of the pause between consecutive impulses in milliseconds. Allowed range: from 100 ms to 1209600000 ms (14 days).
`working_mode`	Optional parameter that defines the input control mode. Supported values: `dlatch`, `oneshot`, `edgereset`, `leveldriven`.

Input handling

The block supports two commands from the command block regardless of the configured working_mode:

The set command from the command block starts the generator. If the generator is already running, the sequence restarts from the working phase and the impulse counter is initialized from the beginning.
The reset command from the command block stops the generator and switches it to the idle state.

If no other block is connected to the block input, the generator starts automatically after project initialization is complete.

In the dlatch, oneshot, and edgereset modes, the input reaction depends on the input_edge parameter:

rising: react to a false -> true change
falling: react to a true -> false change
both: react to every logical value change
true: react to every message whose new value is logical true
false: react to every message whose new value is logical false
null: react to every message whose new value is null
none: no reaction to regular input events

Input values other than those supported by the selected trigger condition are ignored. In particular, for rising, falling, both, true, and false, the block requires values that can be interpreted logically, while for null it reacts only to the null value.

Other input signals are handled according to the working_mode parameter:

Working mode	Description
Edge started and stopped (`dlatch`)	Every event matching the `input_edge` condition toggles the generator between start and stop. When the generator is stopped, such an event starts it. When the generator is already running, the same event stops it.
Edge triggered (`oneshot`)	An event matching the `input_edge` condition starts the generator only when it is idle. Input events received while the generator is running are ignored.
Extended by the edge (`edgereset`)	An event matching the `input_edge` condition starts the generator if it is stopped. If the generator is already running, the next event does not restart the current phase and does not reset the current timer, but it restores the remaining impulse counter to the value from the configuration, so the generator runs longer.
State driven (`leveldriven`)	Logical true starts the generator if it is not already active. Logical false stops the generator. In this mode, the `input_edge` parameter does not affect the start and stop decision, and non-logical values are ignored.

The block does not require the use of inputs labeled using the tag block.

Block outputs

Output number and name	Output description
1. Working phase.	Returns true only when the generator is in the working phase of an impulse. In all other states it returns false.
2. Sleeping phase.	Returns true only when the generator is in the sleeping phase between impulses. In all other states it returns false.
3. Generator active.	Returns true when the generator is active, meaning it is either in the working phase or in the sleeping phase. In the idle state it returns false.

The relationship between the outputs is as follows:

in the idle state all three outputs are false
in the working phase the outputs are: true, false, true
in the sleeping phase the outputs are: false, true, true

Block status description

The description visible below the block has one of two values:

idle means that the generator is stopped
active means that the generator is currently in the working phase or in the sleeping phase

The active status does not distinguish between the working phase and the sleeping phase. Use the block outputs to tell them apart.

Errors visible to the user

The block can display the following error messages:

Error code	Error description
`Invalid edge configuration.`	The `input_edge` parameter is invalid or was not provided.
`Invalid impulses number configuration.`	The `impulses` parameter has an invalid value.
`Invalid working_time configuration.`	The `working_time` parameter is outside the allowed range from 100 ms to 14 days.
`Invalid sleeping_time configuration.`	The `sleeping_time` parameter is outside the allowed range from 100 ms to 14 days.
`Invalid working_mode configuration.`	The `working_mode` parameter has a value other than `dlatch`, `oneshot`, `edgereset`, or `leveldriven`.
`Failed to create timer.`	The internal timer used to measure time could not be created while starting the generator.
`Failed to start timer.`	The timer could not be started when the generator started or when switching between the working and sleeping phases.
`Failed to stop timer.`	The timer could not be stopped while turning the generator off.

Messages starting with Failed to ... indicate an internal problem with the block rather than an invalid value provided by the user. If such a problem occurs repeatedly, it is worth checking the project configuration and the block connections, and then reporting the issue.

Examples

For impulses = 1, working_time = 1000, and sleeping_time = 500, after being started the generator will go through a working phase lasting about 1 s, then a sleeping phase lasting about 0.5 s, and then return to the idle state.
For impulses = 3, the generator will execute three working phases separated by three sleeping phases and will stop only after the final sleeping phase ends.
For impulses = 0, the generator will alternate between the working phase and the sleeping phase indefinitely until it receives the reset command from the command block or a stop signal consistent with the selected working mode.
In dlatch mode with input_edge = rising, the first rising edge will start the generator and the next rising edge will stop it.
In oneshot mode with input_edge = rising, a rising edge will start the generator only when it is in the idle state. Further rising edges received while it is running will be ignored.
In edgereset mode with impulses = 5 and input_edge = rising, the next rising edge received while the generator is already running will not restart the current phase, but it will extend the total run time by restoring the remaining impulse counter.
In leveldriven mode, true starts the generator and false stops it. Values other than logical values are ignored in this mode.
If nothing is connected to the block input, the generator starts automatically after project initialization is complete.