Since tension always affects the flatness to some extent, a perfect flatness measurement must be done without tension. One possibility for this is usually at the end of the line, after the exit looper. In many lines there is an inspection table here which can be used if a scanning VeriFlat–gauge is installed on top of the table.
When the strip is stopped and tension released, a VeriFlat-sensor can scan a strip section (typically 2-3 meters). The result will be a sample measurement under perfect conditions. Any number of measurements can be done as long as the time permits. A scanning takes 5-10 seconds.
The sensor can also measure the whole strip under tension. The result will be a complete strip measurement with a number of high quality sample measurements (see figure below).