It would be nice if gearing was all you required - but that would only be appropriate if you wanted 50.292 inch cuts.
The rotary knife should be following a cam profile that suits the desired cut length. A linear segment is required for the duration of knife contact with the board with unity slope (speed match). (Hint: scale the knife axis for inches of circumference). The rest of the profile needs to cover the cut length with accel and decel before and after the linear segment, which I would place so as to straddle the rollover of the profile (i.e begin and end at bottom dead centre).
I haven't worked with GML for a few years, but last time I checked, it only offered linear interpolation between profile points and so you will need to create a number of points to achieve the accel and decel curves. Pity you're not using ControlLogix.
Set up two profiles - one for product and one for sample. When a sample is required, trigger the sample profile as a pending cam, then when it is in operation, re-trigger the product cam (also as pending).
Of course, it all depends on whether the motors and drives have been sized to do the job.
The rotary knife should be following a cam profile that suits the desired cut length. A linear segment is required for the duration of knife contact with the board with unity slope (speed match). (Hint: scale the knife axis for inches of circumference). The rest of the profile needs to cover the cut length with accel and decel before and after the linear segment, which I would place so as to straddle the rollover of the profile (i.e begin and end at bottom dead centre).
I haven't worked with GML for a few years, but last time I checked, it only offered linear interpolation between profile points and so you will need to create a number of points to achieve the accel and decel curves. Pity you're not using ControlLogix.
Set up two profiles - one for product and one for sample. When a sample is required, trigger the sample profile as a pending cam, then when it is in operation, re-trigger the product cam (also as pending).
Of course, it all depends on whether the motors and drives have been sized to do the job.