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Algorithm for Reducing Speed of Forms Movement based upon Cover or Door Sensors

IP.com Disclosure Number: IPCOM000103934D
Original Publication Date: 1993-Feb-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 6 page(s) / 209K

IBM

Related People

Ethington, B: AUTHOR [+2]

Abstract

Disclosed is an algorithm to slow the paper speed to a safe rate after the cover or door on the printer is opened. This invention utilizes an interrupt triggered by sensors which detect when the cover or door is opened. The paper speed will slow from 10 inches per second to .25 inches per second for a host initiated move and 10 inches per second to 5 inches per second for operator panel initiated moves. If the cover or door is closed during the host initiated move the speed will increase back to 10 inches per second.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 22% of the total text.

Algorithm for Reducing Speed of Forms Movement based upon Cover or Door Sensors

Disclosed is an algorithm to slow the paper speed to a safe
rate after the cover or door on the printer is opened.  This
invention utilizes an interrupt triggered by sensors which detect
when the cover or door is opened.  The paper speed will slow from 10
inches per second to .25 inches per second for a host initiated move
and 10 inches per second to 5 inches per second for operator panel
initiated moves.  If the cover or door is closed during the host
initiated move the speed will increase back to 10 inches per second.

The interrupt discussed above is generated by an ASIC.  When
the interrupt from the opening of the cover or door is received, the
algorithm determines if the paper motor is moving.  If it is not,
then a flag is set to signal the forms motor to move slow for the
next move.  If the motor is moving when the interrupt occurs the
algorithm determines what step in the move is in process.  When the
motor step in process is determined, the ramp table pointer is
adjusted to point to the ramp down steps.  The ramp table consists of
discrete step times which are used to determine the time between
steps on the paper motor.  The interlock interrupt is an asynchronous
event; therefore, it is important that the algorithm be flexible and
can reach the ramp down steps from any point in the ramp table.
Also, different ramp tables are used for different forms devices such
as Continuous Forms Module (CFM), Dual Purpose Module (DPM), Document
Insertion Device (DID), and Auto Sheet Feeded (ASF) Therefore, the
algorithm must be paper device dependent.

When the interrupt occurs, the motor is then ramped down to
zero velocity.  When the motor reaches zero velocity, the software
checks to see if more steps are remaining in the move and if the
cover or door is still open.  If more steps are remaining in the move
after the motor has reached zero velocity, the motor will begin
moving at .25 inches per second for all non-operator panel moves and
5 inches per second for operator panel moves.  The .25 inches per
second speed is attained by taking 4 consecutive steps then stopping
for 30 milliseconds.  If the cover or door is closed during the .25
inches per second velocity the paper motor is again ramped down to
zero velocity and ramped up to a speed dependent upon the number of
steps remaining in the move.  However, if the move is initiated by
the operator panel the motor speed is sufficient to complete the move
in a reasonable time; therefore, no increase in speed will be
performed if the cover or door is closed.  The algorithm to slow the
paper speed is shown and it is split into two separate groups.
First, the Forms Sensor Interrupt routine and the Interlock Sensor
routine are executed by the interrupt handler.  These routines set up
the correct flags and variables when the cover or door is opened for
the second group.  The se...