Method and apparatus for determining coil sheet length

A computer method of determining the coil length of sheet material moving in contact with a length measuring roll and subsequently coiled on a coiler mandrel, which comprises:

• a. generating a sheet length measuring signal at said roll which includes slippage errors when slippage occurs between said sheet material and said roll,
• b. generating a fractional coil wrap signal and a coil wrap number signal at said coiler mandrel,
• c. computing a slippage-error compensated sheet length measuring signal,
• d. computing the integral of the compensated sheet length measuring signal between limits represented by the coil wrap number signal, and
• e. computing a partial last wrap length signal from the fractional coil wrap signal and adding same to the signal from step (d) to determine the total coil sheet length.

A computer method of determining the coil length of sheet material moving reversibly in contact with a length measuring roll and subsequently coiled on a coiler mandrel, which comprises:

• a. generating a sheet length measuring signal at said roll which includes slippage errors when slippage occurs between said sheet material and said roll,
• b. generating first and second coil wrap signals at said coiler mandrel,
• c. sensing the direction of sheet movement based on a predetermined characteristic of said first and second coil wrap signals,
• d. computing a slippage-error compensated sheet length measuring signal effective for only one direction of sheet movement, and
• e. computing the integral of the compensated sheet length measuring signal between limits represented by one of the coil wrap signals to determine coil sheet length in one direction of sheet movement.

Apparatus for determining the coil length of sheet material moving in contact with a length measuring roll and subsequently coiled on a coiler mandrel, said apparatus comprising:

• a. means coupled to said roll for generating a sheet length measuring signal which includes slippage errors when slippage occurs between said sheet material and said roll,
• b. means coupled to said coiler mandrel for generating a coil wrap signal,
• c. programmed computer means including computer program means for performing the following functions in sequence:
• 1. computing a slippage-error compensated sheet length measuring signal, and
• 2. computing the integral of the compensated length measuring signal between limits represented by the coil wrap signal for determining coil sheet length.

Apparatus for determining the coil length of sheet material moving in contact with a length measuring roll and subsequently coiled on a coiler mandrel, said apparatus comprising:

• a. means coupled to said roll for generating a sheet length measuring signal which includes slippage errors when slippage occurs between said sheet material and said roll,
• b. means coupled to said coiler mandrel for generating a fractional coil wrap signal and a coil wrap number signal,
• c. programmed computer means including computer program means for performing the following functions in sequence:
• 1. computing a slippage-error compensated sheet length measuring signal,
• 2. computing the integral of the compensated sheet length measuring signal beween limits represented by the coil wrap number signal, and
• 3. computing a partial last wrap length signal from the fractional coil wrap signal and adding same to the integrated sheet length measuring signal for determining the totalcoil sheet length.

Apparatus for determining the coil length if sheet material moving reversibly in contact with a length measuring roll and subsequently coiled on a coiler mandrel, said apparatus comprising:

• a. means coupled to said roll for generating a sheet length measuring signal which includes slippage errors when slippage occurs between said sheet material and said roll,
• b. means coupled to said coiler mandrel for generating first and second coil wrap signals,
• c. means responsive to the first and second coil wrap signals for sensing the direction of sheet movement and producing first and second control signals,
• d. programmed computer means including computer program means for performing the following functions in sequence:
• 1. computing a slippage-error compensated sheet length measuring signal in response to said first and second control signals and effective for computation in only one direction of sheet movement, and
• 2. computing the integral of the compensated sheet length measuring signal between limits represented by one of the coil wrap signals to determine coil sheet length in one direction of sheet movement.