Chart recorders

Abstract

In a potentiometric chart recorder, the speed of the chart motor 22 is, in one mode of operation (AUTO) selected by a switch 32, varied between two values in dependence upon the rate of change or slope of the input signal at 10 as detected in a detector 30. The slow speed is obtained by intermittent operation at the fast speed, and during the non-operative periods power-consuming circuitry e.g. 16, 18, 26 is switched off by a switch 40.

I claim: .[.1. A chart recorder, comprising: 
     
        change of said magnitude..]. 3. A recorder according to claim .[.1.]. .Iadd.28.Iaddend., wherein said second drive means includes a motor rigidly connected to the recording member, and including limit switches 
     
     
        for disabling said motor upon actuation of the limit switches. 4. A recorder according to claim .[.1.]. .Iadd.28.Iaddend., wherein said second drive means includes a potentiometric position sensor. .[.5. A chart recorder according to claim 1, including means for detecting the slope of the input signal by periodically sampling the input signal and comparing 
     
     
        successive samples..]. 6. A recorder according to claim .[.1.]. .Iadd.33.Iaddend., wherein at least one of said drive means includes a 
     
     
        drive motor provided with a velocity control circuit. 7. A recorder according to claim 6, wherein said velocity control circuit comprises a memory circuit having an input connected to said motor through a first switch an an output connected to a comparator which also receives a motor control signal, the comparator output being applied to said motor through a second switch and a power amplifier, wherein said first and second switches are closed alternately. .[.8. A recorder according to claim 1, wherein said first drive means is adapted to switch between two or more 
     
     
        predetermined rates in response to the slope of said input signal..]. 9. A recorder according to claim .[.8.]. .Iadd.33.Iaddend., including manually-operable means for disconnecting said first drive means from said input terminal and causing the record medium to be relatively moved past 
     
     
        the recording member at a selected constant speed. 10. A recorder according to claim .[.8.]. .Iadd.33.Iaddend., including means responsive to said first drive means operating at a selected rate to provide a visual 
     
     
        indication thereof on the record. 11. A recorder according to claim 10, wherein said last-mentioned means applies an oscillatory signal to the 
     
     
        second drive means to vary the width or thickness of the record. .[.12.  A recorder according to claim 8, wherein said first drive means switches between a fast speed and a slow speed, and the slow speed is obtained by 
     
     
        intermittently operating the recorder at the fast speed..]. 13. A recorder according to claim .[.12.]. .Iadd.33.Iaddend., wherein, when in the slow speed condition and during the non-operative periods, at least some of the 
     
     
        recorder circuitry is disconnected from its power supply. 14. A recorder according to claim .[.12.]. .Iadd.33.Iaddend., including means causing the second drive means to provide a periodic time indication on the record, and for simultaneously causing the record member to be relatively moved past the recording member even if the time indication occurs during one of 
     
     
        the non-operative periods. .[.15.  A chart recorder, comprising: an input terminal for receiving an electrical input signal a value of which is to be recorded;   first drive means including circuitry and for relatively moving a length of record medium past a recording member at a selectable controlled rate; and   second drive means including circuitry and connected to said input terminal for relatively moving the recording member across the record medium to a position dependent upon the value of said input signal;   means for selectively operating the first drive means at a fast speed or a slow speed and obtaining the slow speed by intermittent operation at the fast speed, and means responsive to selection of the slow-speed condition for disconnecting, during the non-operative periods, at least some of said circuitry from its power supply, whereby power consumption is reduced..]. .[.16. A recorder according to claim 15, wherein at least one of said drive means includes a drive motor provided with a velocity control circuit..]. .[.17. A recorder according to claim 16, wherein said velocity control circuit comprises a memory circuit having an input connected to said motor through a first switch and an output connected to a comparator which also receives a motor control signal, the comparator output being applied to said motor through a second switch and a power amplifier, wherein said first and second switches are closed alternately..].   
     
     
        .Iadd.     A chart recorder, comprising: an input terminal for receiving an electrical signal, a value of which is to be recorded; and   recorder circuitry connected to the input terminal, the recorder circuitry including:   first drive means for moving a length of record medium relative to a recording member; and   second drive means connected to said input terminal for relatively moving the recording member across the record medium to a position dependent on the said value of the input signal;   at leat one of said drive means including a drive motor provided with a velocity control circuit comprising a memory circuit having an input connected to said motor through a first switch and an output connected to a comparator which also receives a motor control signal, the comparator output being applied to said motor through a second switch and a power amplifier, wherein said first and second switches are closed alternately. .Iaddend. .Iadd.19. A recorder according to claim 28, wherein the first drive means is connected to the input terminal and is responsive to the input signal in such a manner that the speed at which the record medium is moved relative to the recording member is dependent on a characteristic of the input signal. .Iaddend. .Iadd.20. A recorder according to claim 19, wherein the said characteristic is the rate of change of said value. .Iaddend. .Iadd.21. A recorder according to claim 19, wherein said value   
     
     
        of said input signal is its magnitude. .Iaddend. .Iadd.22.  A recorder according to claim 18 including means for detecting the slope of the input signal by periodically sampling the input signal and comparing successive samples. .Iaddend. .Iadd.23. A recorder according to claim 22 wherein said first drive means is operable to move said length of record medium at a fast or slow speed in response to the slope of the input signal detected by said means for detecting. .Iaddend. .Iadd.24. A chart recorder according to claim 23 in which the chart recorder is a portable, battery powered unit, said recorder circuitry being powered at a battery supply connection, said first drive means comprising a chart motor connected to said recording medium, means powered by said battery supply connection and in turn connected for supplying a stabilized voltage to said chart motor and therewith moving said record medium at said fast speed, first switch means interposed between said stabilized voltage supply means and chart motor and closeable and openable to respectively (1) turn on said chart motor to operation at a given instantaneous speed and (2) turn off said chart motor, speed selection means alternately actuable (1) for holding said first switch means closed to thereby select said fast speed of record medium movement and (2) for holding said first switch means open, except for intermittent closing, to thereby select said slow speed record medium movement by operating the chart motor at the same instantaneous speed as in the fast speed mode but for only a part of the time. .Iaddend. .Iadd.25. A recorder according to claim 24 including a brake actuable by said speed selection in response to said slow speed selection for quickly stopping chart motor movement in concert with said opening of said first switch. .Iaddend. .Iadd.26. A chart recorder according to claim 25, wherein, when in the slow speed condition and during the non-operative periods, at least some of the recorder circuitry is disconnected from its 
     
     
        power supply. .Iaddend. .Iadd.27.  A chart recorder, comprising: an input terminal for receiving an electrical input signal a value of which is to be recorded;   means for detecting the slope of the input signal by periodically sampling the input signal and comparing successive samples; and   recording circuitry connected to the input terminal, the recorder circuitry including:   first drive means for moving a length of record medium relative to a recording member at a fast or slow speed in response to the value of the slope of the input signal detected by the means for detecting; and   second drive means connected to said input terminal for relatively moving the recording member across the record medium to a position dependent on the said value of the input signal;   said second drive means including a motor rigidly connected to the recording member and including limit switches for disabling said motor upon actuation of said limit switches. .Iaddend. .Iadd.28. A recorder according to claim 27 wherein the first drive means is constructed so that the said fast speed is obtained by operating the drive means continuously and the slow speed is obtained by operating the first drive means intermittently at the said fast speed. .Iaddend. .Iadd.29. A chart recorder, comprising:   an input terminal for receiving an electrical input signal, a value of which is to be recorded;   means for detecting the slope of the input signal by periodically sampling the input signal and comparing successive samples;   recorder circuitry connected to the input terminal, the recorder circuitry including:   first drive means for moving a length of record medium relative to a recording member at a fast or a slow speed in response to the value of the slope of the input signal detected by the means for detecting, the first drive means being constructed so that the said slow speed is obtained by operating the first drive means intermittently at the said fast speed;   second drive means connected to the input terminal for relatively moving the recording member across the record medium to a position dependent on the said value of the input signal, the second drive means including a motor rigidly connected to the recording member;   1imit switches for disabling said motor on actuation of the limit switches;   one of said drive means including a drive motor velocity control circuit comprising a memory circuit having an input connected to said motor through a first switch and an output connected to a comparator which also receives a motor control signal, the comparator output being applied to said motor through a second switch and a power amplifier, wherein said first and second switches are closed alternately;   means responsive to the first drive means operating at a selected speed to provide a visual indication thereof on the record by applying an oscillatory signal to the second drive means to vary the width or thickness of the record; and   means for causing the second drive means to provide a periodic time indication on the record and for simultaneously causing the record medium to be relatively moved past the recording member even if the time indication occurs during one of the non-operative periods. .Iaddend.   
     
     
        .Iadd.0.  A chart recorder, comprising: an input terminal for receiving an electrical signal, a value of which is to be recorded; and   recorder circuitry connected to the input terminal, the recorder circuitry including:   first drive means for moving a length of record medium relative to a recording member selectably at a fast or slow speed;   second drive means connected to said input terminal for relatively moving the recording member across the record medium to a position dependent on the said value of the input signal; and   means responsive to said first drive means operating at a selected speed to apply an oscillatory signal to the second drive means to vary the width or thickness of the record so as to provide a visual indication of said speed on said record. .Iaddend. .Iadd.31. A recorder according to claim 30 including means for detecting the slope of the input signal by periodically sampling the input signal and comparing successive samples. .Iaddend. .Iadd.32. A recorder according to claim 31 wherein said first drive means is operable to move said length of record medium at a fast or slow speed in response to the slope of the input signal detected by said   
     
     
        means for detecting. .Iaddend. .Iadd.33.  A chart recorder, comprising: an input terminal for receiving an electrical input signal a value of which is to be recorded;   means for detecting the slope of the input signal by periodically sampling the input signal and comparing successive samples; and   recorder circuitry connected to the input terminal, the recorder circuitry including:   first drive means for moving a length of record medium relative to a recording member at a fast or slow speed in response to the value of the slope of the input signal detected by the means for detecting; and   second drive means connected to said input terminal for relatively moving the recording member across the record medium to a position dependent on the said value of the input signal;   the chart recorder being a portable, battery powered unit, wherein said recorder circuitry is powered at a battery supply connection, said first drive means comprising a chart motor connected to said recording medium, means powered by said battery supply connection and in turn connected for supplying a stabilized voltage to said chart motor and therewith moving said record medium at said fast speed, first switch means interposed between said stabilized voltage supply means and chart motor and closeable and openable to respectively (1) turn on said chart motor to operation at a given instantaneous speed and (2) turn off said chart motor, speed selection means alternately actuable (1) for holding said first switch means closed to thereby select said fast speed of record medium movement and (2) for holding said first switch means open, except for intermittent closing, to thereby select said slow speed record medium movement by operating the chart motor at the same instantaneous speed as in the fast speed mode but for only a part of the time. .Iaddend.