Packing Machine Print Out problem...

Dear all,

We are working on a biscuit packing machine named dobey.... PLC is Siemens S7 300 with five delta servo motors, the issue we are facing is that we cant maintain the position of black mark i.e. print during running... we try to control from the black mark sensor reference to increase and decrease the speed of motor as per our requirement (encoder pulses) but failed to do so, one thing more that we are running the servos on 0-10V mode not in the positioning mode... we also try create a dead band and check the feedback of the sensor with it but didnt get any success... after doing all we are still at the same position, every time the paper position is out after some packets and we cant run the machine on production....

any help regarding the issue will be highly appreciated..

Regards

Has this ever worked? Are you making a new machine or maintaining an old one? Is it the original machine setup or did you change or add anything, like this printer? If the machine is running fast, the problem could be related to PLC cycle time. What triggers the print signal?