PresenceAlarm

Macro component that raises an alarm when a person is still present while monitoring is on (left-behind alarm), from the target state decoded by Hi_Link_LD2410C.

Processing

Condition_count (RTMaps Condition) counts the samples with the condition (a != 0) * ((s >= 1 && s <= 3) * result + 1): 0 while monitoring_switch is 0, 1 while monitoring and nobody is present, n + 1 after a person has been present for n consecutive samples (target_state 1 to 3).
Condition_alarm latches the alarm with the condition c != 0 && (result != 0 || c > 200): the alarm turns on when the count exceeds 200 samples (about 20 seconds at the report rate of the sensor, about 10 Hz) and stays on until monitoring_switch returns to 0.
Both Condition components are evaluated whenever an input arrives (Synchro tolerance = -1) and output the value of the condition every time.

Usage

Connect Hi_Link_LD2410C.target_state → target_state, and a 0/1 switch signal that means that nobody should be here from now on (door lock, door-closed switch, ignition off, end of a task; a Bi-state button for tests) → monitoring_switch. Connect alarm to an LED, a buzzer or a recorder.
A person who leaves the detection range after monitoring starts becomes absent after the no-one duration of the sensor (default 5 s) and the count returns to 1, so no alarm is raised when leaving plus the no-one duration takes less than about 20 seconds. A person who stays (even motionless, detected by breathing) raises the alarm.
Defined in SMSL_BasicToolkit_Macros.rtmc.

Data format

Inputs and outputs: Integer32 scalars, one output sample per evaluation.

Notes

Time is counted in samples, so the alarm delay changes with the report rate of the sensor. The threshold (200 samples) is in the condition of Condition_alarm; the macro has no properties, so edit the macro (.rtmc) to change it.
target_state 4 to 6 (background noise detection) counts as absent.
When the sensor stops reporting, the outputs stop and keep their last values.
Not a safety device (not certified for functional safety); to protect people, use it only as an aid to a certified sensor.

Outputs

Name	Description
`alarm`	Alarm: 1 when a person has been present for more than 200 samples while monitoring, latched until monitoring_switch returns to 0; otherwise 0. Type: `Integer32`
`monitor_count`	Count: 0 = not monitoring, 1 = monitoring and nobody present, n + 1 = a person has been present for n consecutive samples. Type: `Integer32`

Inputs

Name	Description
`monitoring_switch`	Monitoring switch: non-zero (1) = on, 0 = off. Turning it off resets the count and the alarm. Type: `Integer32`
`target_state`	Target state from Hi_Link_LD2410C: 0 none, 1 moving, 2 stationary, 3 both (4 to 6: background noise detection, counted as absent). Type: `Integer32`