The internal chronometer was a part of a Soong-type android's construction. It functioned as a timekeeping device and could be switched off. (TNG: "Timescape" ) Data's internal chronometer was stopped by the solanogen-based lifeforms when they abducted the android. When comparing his internal chronometer to the USS Enterprise-D's chronometer, Data realized that he had been off the ship for more than ninety minutes. (TNG: "Schisms" ) In 2370, Data's dream program caused him to oversleep, but it was not due to a problem with his internal chronometer. (TNG: "Phantasms" )