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Multichannel Recording Using Pen Chart Recorder

IP.com Disclosure Number: IPCOM000050093D
Original Publication Date: 1982-Sep-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 64K

Publishing Venue

IBM

Related People

Boyd, RE: AUTHOR

Abstract

This system accepts electrical input signals from a variety of sensors, conditions the signals to an appropriate scale factor, and controls the application of the signals to a single pen chart recorder. The time shared multichannel chart recording with a common time base permits measurement and analysis of various signal input levels and events.

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Multichannel Recording Using Pen Chart Recorder

This system accepts electrical input signals from a variety of sensors, conditions the signals to an appropriate scale factor, and controls the application of the signals to a single pen chart recorder. The time shared multichannel chart recording with a common time base permits measurement and analysis of various signal input levels and events.

Circuits are provided for protecting the recorder from over voltage signal inputs, and a means is provided to record and determine the magnitude of the over voltage signal.

Referring to Fig. 1, the basic clock signal is provided by clock 1 which is an input to a 1 in 10 counter 3. The frequency of the clock is determined by an R-C network, and the clock may be stopped by the operation of a stop switch 5.

Counter 3 advances one position when pulsed by a clock signal. When the count reaches 6, the counter is reset to 1 at the next pulse and continues counting upward with each succeeding input pulse until it resets. Reset at the counts of 7, 8, 9 or 10 is provided depending upon the setting of reset switch 7. The counter may be manually advanced by the operation of the advance switch
9.

Buffer amplifier 11 receives four output signals from the 1 in 10 counter. It amplifies and distributes each of the signals to four electronic switches 13A-13D, and a status indicator 15. The four electronic switches are sequentially operated under control of the counter 3 and buffer 11. Each switch is provided with an analog sensor input signal from an electrical network (N1 through N4) which conditions the signal to the appropriate chart recorder voltage scale. The switch output lines are electrically combined to form a common analog signal data bus
17. The control line to each electronic switch is also applied to a respective display segment of status indicator 15 to indicate which of the four signals is active.

Flip flops FF-1 and FF-2 are each connected to toggle alternately "on" and "off" with an incoming series of pulses from buffer 11. These outputs are used ultimately to control four additional electronic switches which are connected in the same manner as 13A-13D, so that, overall, 1 of 8 input signals is sequentially sampled. The signal selected is then provided to the analog data bus. The toggle function, however, further time shares the signal sequence from the flip flops such that a given electronic switch 19A-19D is selected every other time an input is provided to its controlling flip flop. The electronic switch control signals are also used to turn on a corresponding segment of the status indicator 15.

The resulting electronic switch selection and status display is illustrated in Fig. 2. In this illustration the 1 in 10 counter is controlled to reset after six counts.

As can be seen, electronic switches 13A-13D are turned on twice in each sequence of twelve clock pulses; however, electronic switches 19A-19D are turned on only once in each sequence...