A mass flowmeter of the thermal type, having a planar, thin substrate with a sensing surface that can be brought into direct or indirect contact with a flowing fluid during a measurement, wherein electrically controllable heating elements and temperature sensor elements for determining a temperature difference are provided on the sensing surface by a planar technique. One exemplary method may include discovering a connection to a service providing networked device, client-side associating the connection, validating the connection before initiating a service request to the service providing networked device, selectively rediscovering the service providing networked device, and selectively client-side reassociating the connection. The test devices with contact pads at opposite ends of the bottom electrode allow resistance across the bottom electrode to be measured as a surrogate for measuring resistance between the top and bottom electrodes. At every other time the trap potential prevents the penetration of electrons into the ion cloud, since their local potential is always more negative than that of the electron source, so that the negatively charged electrons are repelled.