2. Operation
3. Special Guiding and Monitoring Functions
4. Watchdog
5. Function

Function

The Watchdog function is used to prevent the web from wandering after the total loss of the printed line or contrast transition during line or contrast guiding. If the printed line or the contrast transition disappear from the scanning area of the line and contrast sensor (e.g. if the print is not carried out, a poor splice or similar), the current web position is detected by the edge sensor (capture sensor) and saved by the controller. Then the controller will switch over from the line and contrast sensor (Sensor 3) to the edge sensor (Sensor 1 or Sensor 2) used. Switching back to the line and contrast sensor is carried out automatically immediately after re-detecting the printed line or the contrast transition. When the Watchdog function is activated, the scanning area of the capture sensor is limited to 80%.