Code Marks placed on the web in an upstream process usually indicate a value for transfer of information to a downstream process. Most commonly these codes represent linear length within a roll, but may also contain other information such as defect locations in the cross-web position, lot numbers, or other alpha-numerical values. Decoding is typically performed on secondary processes like rewinding or converting/slitting.
A Decoding System is usually a spot sensor or small camera that is specially tuned to see only the color of the codes made upstream. A spot sensor works well when there is no web wander at the point of detection, while cameras work well when there is lateral web wander where marks need to be detected, giving a typical 2”-wide field of view. Special lighting may also be required for the camera to detect the code marks.
As the codes move into the field of field of view of the sensor/camera, the individual code bits are read as 24 VDC pulses by the RYECO Decoding System. Using an encoder signal, the RYECO PLC translates the code bits into a discrete value using RYECO’s proprietary decoding software. Decoded values are then displayed on the system’s HMI along with an overall decoding status. Decoded values can be sent to other control devices via a serial string, or can simply trigger a 24 VDC output from the RYECO system.