Skip to content

topic_state_monitor#

Purpose#

This node monitors input topic for abnormalities such as timeout and low frequency. The result of topic status is published as diagnostics.

Inner-workings / Algorithms#

The types of topic status and corresponding diagnostic status are following.

Topic status Diagnostic status Description
OK OK The topic has no abnormalities
NotReceived ERROR The topic has not been received yet
WarnRate WARN The frequency of the topic is dropped
ErrorRate ERROR The frequency of the topic is significantly dropped
Timeout ERROR The topic subscription is stopped for a certain time

Inputs / Outputs#

Input#

Name Type Description
any name any type Subscribe target topic to monitor

Output#

Name Type Description
/diagnostics diagnostic_msgs/DiagnosticArray Diagnostics outputs

Parameters#

Node Parameters#

Name Type Default Value Description
update_rate double 10.0 Timer callback period [Hz]
window_size int 10 Window size of target topic for calculating frequency

Core Parameters#

Name Type Default Value Description
topic string - Name of target topic
topic_type string - Type of target topic
transient_local bool false QoS policy of topic subscription (Transient Local/Volatile)
best_effort bool false QoS policy of topic subscription (Best Effort/Reliable)
diag_name string - Name used for the diagnostics to publish
warn_rate double 0.5 If the topic rate is lower than this value, the topic status becomes WarnRate
error_rate double 0.1 If the topic rate is lower than this value, the topic status becomes ErrorRate
timeout double 1.0 If the topic subscription is stopped for more than this time [s], the topic status becomes Timeout

Assumptions / Known limits#

TBD.

Back to top