fooltech

Thanks for everyone's help have just about succeeded using the following (Line Speed / Radius of Roll) X (Freqmax/(2 x pi x Nmax)) = Required Frequency Freqmax = Maximum Frequency of Inverter (Hz) Nmax = Measured Output of Gearbox at Max Frequency (rpm) Line Speed = mm/min Radius of Roll =mm Scaled the two inputs to engineering units and worked from there, slight difficulty in that for as yet unexplained reasons at certain speeds the drive is cycling around the set speed but think this is inverter set up and will need to do more work on this. Have cured it by altering the Nmax number using an SPC function based on roll diameter which seems to indicate that load on the drive is having an impact as well. This generates a number in Hz from 0 to max which I then put into an SPC to drive output card Eurotherm good drives but Telemecanique usually 2/3 cost well to us anyway

Hi I am using a Telemecanique ATV 31 inverter newer ATV 71 would probably do the job but have got to use what I've got for the moment. Decided to split curve into 4 linear sections on the basis that even a circle is made up of straight lines. Using the SPC instruction and limiting the line speed I am having reasonable success just trying find the roll over points from 1 line to the next at the moment. When I think I understand what is going on with one line speed range I will look at the others, biggest problem is that web has to be more or less tensionless.

Hi The output required to the inverter to control speed is non linear I have been playing with a fixed line speed for the moment trying to establish some parameters and will get back when I have sorted it out. Dancing roller is not possible because of space constraints and the nature of the product. Have never used look up tables before has anybody any idea where I could find a sample. Thanks

I have to unwind material from a drum at a rate variable from 5 to 20metres per minute I have as 0-10v input and can sense the diameter of the roll (0-10v) I have an inverter which can control the rotational speed of the roll but I am looking for ideas for controlling input to inverter because obviously it will be a non linear reponse ie higher rate of change of speed as roll gets smaller Will be using SLC5/03 Any suggestions would be greatfully received.