SU241539A1 - DEVICE FOR AUTOMATIC SELECTION OF LIMITS OF MEASURING DIGITAL DEVICES - Google Patents

Description

The invention relates to the field of digital instrumentation and is intended for use in digital devices of pulse counting coding.

In the known devices for automatically selecting the limits of measurement of digital devices, the selection of the limit can be carried out only in one direction, i.e., the limits of measurement are sequentially polled from the bottom up or from the top down. With such a choice of the limit of measurement, the instrument cannot operate with high accuracy in the following mode of operation, and it takes considerable time to select the limit for each measurement.

The proposed device provides speed and automatic tracking of the measured value both when it is increased and decreased, regardless of the type of the measured parameter.

This is achieved by the fact that in it the outputs of the higher / dth and preceding () th bits of the pulse counter are connected to the trigger limit register inputs through a series of coincidence circuits, and the outputs of this register are connected in parallel with the switching unit of the reference circuits elements and an indicator of measurement limits. The drawing shows a block diagram of a device for automatic selection of measurement limits.

The device contains a converter / parameter - the number of pulses, a pulse counter of the series-connected counting cells 2, 3 and 4, unit 5 for setting measurement cycles, Formulation 6 control pulses, unit 7 of reference elements, triggers 8, 9 and 10, coincidence circuits 11-19 , collector circuits 20 and 21, overflow indicator 22 at the upper measurement limit, and measurement limit indicator 23.

When manually selecting the limit, the reference element of the transducer parameter - the number is selected by the operator in accordance with the measured value, if its value is approximately known, or according to the degree of filling of the conversion unit.

The proposed device provides a transition from one measurement limit to another without operator intervention. At the same time, the device continues to operate at this limit until the static value or parameter of the dynamically changing process goes beyond the selected measurement range.

Assume that the previous measurement cycle occurs at the lower limit. In this case, the triggers 5 and P of the limit register are in the zero state, and the trigger 10 is in the unit state. The signal from triggers 8 and 9 opens the coincidence circuit 16 and includes the element of the lower measurement limit in block 7. The next measurement from the 5-cycle block starts the driver 6 for the control pulses, from the output of which three control signals of the circuit are output: "Reset," Measure, "Limit . From the "Reset" signal, the counting unit and trigger 10 are set to zero, the instrument performs the measurement operation by the "Measurement" signal, and the "Limit" pulse goes to the new limit if it does not correspond to the value of the measured parameter. In the event of overflow of the conversion unit in the design of this cycle, the output signals from the non-register cells 5 and 4 signal the need to go to the middle limit. A trigger 10 is shifted from the signal from the recalculating cell 3 into one state, the coincidence circuit 12 closes, prohibiting the passage of the "Limit from the driver 6 of control pulses. The overflow signal from the recalculation cell through the coincidence circuit 11 sets the trigger 8 to one state. From the new state of the triggers 5 and 5, the coincidence circuit 17 operates, including the reference element of the average measurement limit. At the same time, the disconnect signal of the lower measurement limit from the coincidence circuit 16 via the collector circuit 21 starts the shaper 6 and-pulses to re-measure this parameter at the middle limit. The overflow of the conversion unit at the end of the parameter measurement at the middle limit indicates the need to move to the upper limit. The signal from the recalculation cell 3 transfers the trigger 10, and the coincidence circuit 12 closes, prohibiting the passage of pulses to the limit of the driver 6. The single state of the trigger 8 closes the coincidence circuit 11 and passes the overflow signal from the recalculation cell 4 through the coincidence circuit 14. This signal transfers trigger one to 9, and the output signal from its collector returns trigger 8 to zero. The new state of triggers S and 5 through the coincidence circuit 18 includes the reference element of the upper limit of measurement. The trip signal from the output of the inhibitor circuit 17 through the collector circuit 21 again starts the driver 6, repeating the parameter measurement at the upper limit. However, it is possible that when measuring at the upper limit an overflow of the counting unit also occurs, the output signals from the 3 vi 4 cells set the triggers 8 and 5 to one state, the coincidence circuit 15 operates, the output signal from it through the indicator 22 signals that it is impossible to measure the parameter of the device and at the same time the collector circuit 20 passes a pulse setting the trigger 8 to the zero state. Thus, the circuit as a whole returns to measure the next unknown parameter at the upper limit and works until the measured value is reduced to the value when the measurement at the middle or lower limit is needed. In case there are no signals from the recalculated cells 3 TL. 4, the trigger 10, remaining in the initial state, resolves the passage of the signal Limit from the driver 6 through the circuit 12 to match the flip-flop of the trigger 9 to the zero state, the trigger 9, in turn, sets the trigger 8 to one state, circuit 17 the match is triggered by including the element of the average measurement limit. When, when measuring a new parameter, signals from recalculated cells 5 and 4 are again absent, then from the signal "Limit from shaper 6 through schemes 12 and 13 coincidences and collecting circuit 20 is set to zero state trigger 8, i.e. the circuit returns to such a state when, through the coincidence circuit 16, the reference element of the lower measurement limit is switched on, at which the instrument continues: to automatically measure the parameters. If at any measurement limit the signal is output from the output of the reference cell 3, but is absent at the output of the cell 4, then the measurement limit is selected correctly and remains unchanged. The measurement of the selected measurement limit is indicated. The device for selecting the limit is shown in the diagram as applied to the three-limit device, but without fundamental changes it can also be used with a larger number of limits. In this case, between tripe1) and 8 and 5 include additional tripers, i.e., they increase the capacity of the trigger register. The subject of the invention is a device for automatically selecting the measurement limits of digital instruments, comprising a pulse counter, triggers and coincidence circuits, characterized in that, in order to ensure tracking of the measured value both at its increase and decrease, regardless of the type of the measured parameter and increase device speed, in it the outputs of the higher “-th and preceding (p-1) -th bits of the pulse counter are connected to the trigger limit register inputs through a series of coincidence circuits, and the outputs of this register and through the block, the coincidence circuits are connected in parallel with the switching unit of the reference elements and the indicator of measurement limits.

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