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Digital Compensation for Train Speed Variations

IP.com Disclosure Number: IPCOM000076786D
Original Publication Date: 1972-Apr-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Halich, VV: AUTHOR [+3]

Abstract

Digital compensation for velocity errors of a type train/chain, caused by loading on the train by print hammers impacting and by deviations in the power-line frequency, can be effected by advancing or delaying the impulse time of the print hammer if the train velocity increases or decreases.

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Digital Compensation for Train Speed Variations

Digital compensation for velocity errors of a type train/chain, caused by loading on the train by print hammers impacting and by deviations in the power- line frequency, can be effected by advancing or delaying the impulse time of the print hammer if the train velocity increases or decreases.

Compensation is accomplished by checking every fourth print scan against a reference time and using the difference to correct the variation. The reference time is close to nominal hammer flight time.

If print scan is 364 mus, for example, the reference time must be greater than three print scans plus 3% (1125 mus) and less than four print scans minus 3% (1414 mus) for a 3% worst case variation. A reference time of 1280 mus was therefore chosen. This is obtained, as shown in Fig. 1, from a 12-stage binary Reference Counter 10, with the 10th and 11th stages preset ON. When a count of 1023 is reached, the first 11 stages are all on and a count of 1024 turns 4096 ON and all the other stages OFF. An additional count of 4095 brings all stages ON and sets a Reference Time Latch 12 during the next oscillator pulse. The elapsed time is 1024 over 2x2 + 4096 over 2x2 = 1280 mus.

The Reference Timer continues to run until a Print Scan pulse occurs, when a Latch Correction Register 14 and a Print Scan Delay Counter 16 will be set with the complement of the Reference Timer. A Scan Start Latch 18 will be reset, allowing the Print Scan Delay C...