This read-only value, in milliseconds, indicates how frequently the agent refreshes the associated entPhySensorValue, with zero meaning the value is updated on demand, only when it changes, or that the agent doesn't know the rate. Admins use it to judge how fresh a polled sensor reading actually is, since a slow update rate means recent changes might not yet be reflected. For example, an update rate of 5000 tells an admin the sensor value is refreshed roughly every five seconds, so polling more often than that gains nothing.