CN201569475U - Bell-jar type gas flux standard device adopting pulse insertion technology - Google Patents

Abstract

The utility model provides a bell-jar type gas flux standard device adopting a pulse insertion technology, comprising a flowmeter output pulse counting device, wherein the flowmeter output pulse counting device comprises a mixed signal processor with a timer and a counter, and a keyboard and a display that are connected with the mixed signal processor; an interrupt signal input terminal of the mixed signal processor is respectively connected with a baffle pulse signal output terminal and the flowmeter pulse signal output terminal of the bell-jar type gas flux standard device; and the mixed signal processor adopts a C8051F350 mixed signal processor. By utilizing the external interrupt input port and internal timer/counter of the mixed signal processor as well as the quick response, processing capability and the interrupt technology, the T1, T2 and N are detected by programming and the practical output pulse number N' is obtained by calculation so that the resolution and accuracy of the flowmeter pulse count can be effectively improved, thus improving the detecting precision of the flowmeter.

Description

Adopt pulse to insert the bell-jar gas flow standard equipment of technology

Technical field

The utility model relates to a kind of bell-jar gas flow standard equipment, relates in particular to the wherein device of flowmeter output step-by-step counting.

Background technology

In recent years, China had increased many gas flow meter hypergenes and had produced enterprise, and flowmeter must be tested or be examined and determine its metering performance before dispatching from the factory or using, with the quality that guarantees product with the accuracy when using.In the gas flow calibration method, bell-jar gas flow calibrating installation is in occupation of crucial status.Bell-jar gas flow standard equipment is that the bell jar useful volume of demarcating with process is the gauging instrument of orthobaric volume, and when bell jar descended, the gas in the bell jar was discharged into calibrated meter through test pipe, and the gas standard volume of discharging with bell jar comes the checking flow instrument.In verification process,, need count flowmeter output umber of pulse by counter during calibrating flowmeter instrument coefficient the flowmeter of output frequency signal.Current flux meter pulse reading adopts the whole pulse number of flow output in the calibrating time to calculate instrument coefficient mostly.But in the calibrating time, the pulse of the actual output of flowmeter and bell jar initial sum stop plate washer signal and asynchronous, and flowmeter output umber of pulse and non-integer, therefore examine and determine the instrument coefficient that obtains and have error, if the calibrating time is short or flowmeter is exported umber of pulse more after a little while, error is bigger relatively.Therefore flowmeter output step-by-step counting technology is studied, significant to improving calibration accuracy.

Summary of the invention

Technical problem to be solved in the utility model provides a kind of bell-jar gas flow standard equipment that adopts pulse insertion technology.

The technical scheme that the utility model adopted is: a kind of bell-jar gas flow standard equipment that adopts pulse insertion technology, comprise flowmeter output pulse counting equipment, described flowmeter output pulse counting equipment comprises mixed-signal processor and keyboard that is connected with mixed-signal processor and the display that is provided with the timer sum counter, and the look-at-me input end of described mixed-signal processor is connected with the baffle plate pulse signal output end and the flowmeter pulse signal output end of bell-jar gas flow standard equipment respectively.Mixed-signal processor adopts the C8051F350 mixed-signal processor.

The beneficial effects of the utility model: utilize the external interrupt input port of C8051F350 mixed-signal processor and abundant timer internal/counter and response and processing power fast, adopt interrupt techniques, programming realizes detecting T1, T2 and N and calculating obtain actual output umber of pulse N ', and (N is the complete pulse sum of flowmeter output, T1 follows first pulse that the initial plate washer signaling traffic of bell jar meter sends, with follow bell jar and stop first pulse that plate washer signaling traffic meter sends, the time interval between these two pulses, T2 is the time interval between the bell jar initial sum termination plate washer signal, and N ' is flowmeter actual output umber of pulse during examining and determine).Flowmeter umber of pulse N ' during the flowmeter instrument coefficient calculates replaces the original N that uses, and effectively improves the resolution and the accuracy of flowmeter step-by-step counting, thereby improves the meter proof precision.

The utility model is described in further detail below in conjunction with the drawings and the specific embodiments.

Description of drawings

Fig. 1 is the circuit block diagram of the device of a kind of embodiment flowmeter output of the utility model step-by-step counting.

Fig. 2 adopts two clocking method schematic diagrams in the pulse insertion technology.

Embodiment

As shown in Figure 1, the flowmeter output pulse counting equipment of present embodiment bell-jar gas flow standard equipment, comprise the mixed-signal processor and keyboard that is connected with mixed-signal processor and the display that are provided with the timer sum counter, the look-at-me input end of described mixed-signal processor is connected with the baffle plate pulse signal output end and the flowmeter pulse signal output end of bell-jar gas flow standard equipment respectively.Described mixed-signal processor adopts the C8051F350 mixed-signal processor.Among Fig. 1, INT1 interrupts detecting the baffle plate pulse, i.e. each baffle plate pulse all can produce an INT1 interrupt request to processor; INT0 interrupts detecting flow pulse, and promptly each flow pulse all can produce an INT0 interrupt request to processor; The counter T0 of processor inside realizes the whole pulse counting, utilizes keyboard or upper machine communication to set starting and ending baffle plate number.Utilize display or host computer to show measurement result.

Two clocking method principles as shown in Figure 2 in the pulse insertion technology of employing said apparatus.Now as follows in conjunction with Fig. 2 brief description:

Bell-jar gas flow standard equipment is that the bell jar useful volume of demarcating with process is the gauging instrument of orthobaric volume, and when bell jar descended, the gas in the bell jar was discharged into calibrated meter through test pipe, and the gas standard volume of discharging with bell jar comes the checking flow instrument.

According to the correlation flowmeters vertification regulation, as velocity flowmeter and gas volume formula flowmeter, the instrument coefficient K of the each calibrating of each calibrating point is

$K=\frac{N}{V}---\left(1\right)$

In the formula, N is a flowmeter output umber of pulse, is that trigger pip begins counting with the initial plate washer of bell jar, stops plate washer with bell jar and finishes counting; The actual volume of V for discharging between the bell jar initial sum termination plate washer.

Stop between the plate washer measuring two time interval T1 and T2 in the flowmeter output complete pulse sum N recording the bell jar initial sum.T1 follows first pulse that the initial plate washer signaling traffic of bell jar meter sends, and follows bell jar and stops first pulse that plate washer signaling traffic meter sends, the time interval between these two pulses; T2 is the time interval between the bell jar initial sum termination plate washer.The umber of pulse N ' of the actual output of flowmeter is calculated by following formula

$N\text{'}=N\frac{T2}{T1}---\left(2\right)$

N N ' in the instrument coefficient K computing formula (1) replaces.

In INT1 baffle plate pulse-break service routine, according to the starting and ending baffle plate of setting number by relatively finishing initial baffle plate and finishing the knowledge of declaring of baffle plate.If initial baffle plate pulse-break then starts the timing of timer start time T2, and it is effective to put T1 timing preparation opening flag, allows INT0 to interrupt.If finish the baffle plate pulse-break, the then timing of control timer stand-by time T2 and obtain the value of timing time T2, putting the T1 timing, to prepare end mark effective, allows INT0 to interrupt.

In INT0 flow pulse interrupt service routine, if it is effective to detect T1 timing preparation opening flag, then start the timing of timer start time T1, start the whole pulse number that internal counter T0 begins the flow of count recording input simultaneously, remove the T1 timing and prepare opening flag.To prepare end mark effective if detect the T1 timing, and then the present flow rate pulse is for finishing pulse, and the timing of control timer stand-by time T1 is also obtained the value of timing time T1, controls internal counter T0 simultaneously and stops counting, and obtain flow whole pulse count value N.The time value T1 that the processor utilization has measured, T2 and flow whole pulse are counted N, can calculate according to formula (2) and obtain actual flow umber of pulse N '.Measurement result can show output or utilize communication interface to give host computer and further handle and use.

Flowmeter output umber of pulse adopts the two clocking methods in the pulse insertion technology during examining and determine, and can effectively improve the resolution and the accuracy of flowmeter step-by-step counting, thereby improves the meter proof precision.

Claims (2)

1. bell-jar gas flow standard equipment that adopts pulse insertion technology, it is characterized in that: comprise flowmeter output pulse counting equipment, described flowmeter output pulse counting equipment comprises mixed-signal processor and keyboard that is connected with mixed-signal processor and the display that is provided with the timer sum counter, and the interrupting input end of described mixed-signal processor is connected with the baffle plate pulse signal output end and the flowmeter pulse signal output end of bell-jar gas flow standard equipment respectively.

2. the bell-jar gas flow standard equipment of technology is inserted in employing pulse according to claim 1, it is characterized in that: described mixed-signal processor adopts the C8051F350 mixed-signal processor.

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