JPS59226997A - One-point adjusting sensor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a sensor for measuring physical quantities such as temperature and humidity, in which the span and zero position of the measurement output can be adjusted in addition to adjusting the zero position of the measurement output. The present invention relates to a single point adjustment sensor that can be brought into a predetermined state.

[Prior art]

In general, in a sensor that measures a physical quantity, as shown in Fig. 1, the measured output M such as voltage or current changes within a predetermined range ΔM for a constant change range ΔP of the physical quantity P, and the measured output M changes within a predetermined range ΔM. It is necessary that the zero position coincides with the zero position of the physical quantity P, and it is also necessary that the state of change in the measured output M shown by the solid line falls within a specified range shown by the dotted line.

On the other hand, in conventional sensors such as temperature sensors, a Ni wire resistor or the like is used as the temperature detection element, and the resistance value of the temperature detection element is converted into a measurement output by an analog circuit, so the circuit is non-linear. This causes individual differences in the slope and zero position due to the change characteristics of the measurement output.

For this reason, a variable resistor is included in the sensor to adjust the zero position,
A variable resistor is provided to adjust the variation of the measured output, that is, the span, for the range of change in the physical quantity, and for the temperature sensor, a resistor with a resistance value that corresponds to the resistance value between the minimum temperature and the maximum temperature of the temperature detection element is provided. Then, connect the resistor corresponding to the lowest temperature in place of the temperature detection element, adjust the zero position variable resistor, then connect the resistor corresponding to the highest temperature, and adjust the span variable resistor. However, since the adjustment statuses of the zero position and the span affect each other, these adjustments have to be repeated, resulting in a disadvantage that the adjustment requires time and effort.

[Summary of the invention]

The present invention has the purpose of fundamentally eliminating the drawbacks of the conventional products, and has the purpose of eliminating the drawbacks of the conventional products. The output of the measurement circuit that processes the electrical output of the quantity detection element has a constant span, and a correction signal generator is provided to send out a correction signal to correct the zero position of the measurement output. On the other hand, the present invention provides an extremely effective one-point adjustment sensor that performs calculations based on correction signals to obtain regular zero position and span measurement outputs.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to figures showing examples.

Figure 2 is a block diagram showing the configuration. 9. A crystal oscillator It's coming out.

The output of the oscillator O8C is amplified to a logic level by the amplifier AMP and then fed to the counter CUT, where the amplified output is counted at every predetermined reference time, and this count value is sent to the calculation section. The count value is converted into a temperature value and then sent to the transmission circuit SR, where the temperature value is converted in response to a polling signal from a solid device not shown in the figure. The data is transmitted as a measurement output to the solid device via the transmission circuit SR and the transmission path.

The control unit CNT, which is composed of a microprocessor, a memory, an input/output circuit, etc., also has a data transmission/reception control function, and is designated by a polling signal given via a transmission path and a transmission circuit SR. This address is compared with the self-specific address set by the address setter As, and if the two match, temperature value data is transmitted.

In addition, the control units C and NT have programs corresponding to various sensor functions stored in the memory in order to achieve common use through high-density integrated circuits, etc., and the address of the memory is stored in the mode setter MS. In this case, the operating mode as a temperature sensor is set by the mode setter MS.

In addition, the crystal oscillator X has its own characteristic deviations.
In order to correct this, a correction signal generator CG is provided, and in order to regulate the operation of the control units C and NT, a pulse generator PG that generates clock pulses is provided with a crystal oscillator Furthermore, a display section DP is provided for the purpose of indicating the obtained temperature value to the control section CNT.

In this case, a three-wire transmission line is used, with line L1 for signals, line L2 for power supply, and line L3 for common use. After stabilizing the power supplied from the solid device via L3 to the power supply circuit ps,
It is supplied to each part as a local power supply E.

Therefore, the measurement output is obtained according to the oscillation frequency generated by the crystal oscillator X as a physical quantity detection element, but the error in the slope exhibited by the temperature versus frequency characteristic of the crystal oscillator In addition, since only the absolute values differ from one another, the output of the measurement circuit consisting of an oscillation circuit or a counter CUT has a constant span, eliminating the need for span adjustment. After obtaining a correction signal for correcting the absolute value and correcting the zero position of the measurement output using the device CG, the controller CNT performs an addition or subtraction operation based on the correction signal on the count output of the counter CUT. , the individual differences in absolute values in the oscillation frequency of the crystal oscillator X are corrected, and a measurement output having a regular zero position can be obtained.

That is, a measurement output having a normal span and zero position can be obtained only by adjusting the zero position of the measurement output using the correction signal generator CG.
□Figure 3 is a circuit diagram showing a specific example of the correction signal generator CG.
Output OU connected to the common circuit by resistors R5-R4
For T 1 to OUT 4, the cathodes of diodes D1 to D4 are individually connected, and the anodes of diodes D1 to D4 are commonly connected and then connected to the input INt. Connect the cathode of D5 and connect the anode of this to input IN2.

Norms signals with different generation times applied to IN2 are output via each diode DI-D5 to OUT1 to OUT.
4 as a correction signal,
By cutting the connection of each diode D1 to D5 according to the situation, it is possible to
This determines the correction value.

That is, when the pulse signal of the input IN2 is sent out via the diode D5, it indicates that the correction value is positive, and when the diode D5 is disconnected and the pulse signal of the input IN2 is not sent out, the correction value is negative. Input I corresponding to the disconnection status of diodes Dl to D4
Depending on the combination of conditions in which the N1 pulse signal is sent, the correction value from 0 to 1.5°C is indicated by a binary code. Therefore, the outputs OUT s to OUT 4 are C.N.
If data is acquired in a time-division manner at T, the correction value and its sign are clear, and the zero position correction of the measurement output is performed based on the above-mentioned calculation.

Note that each setting device MS, As in FIG. 2 may also use the same configuration as in FIG. 3, but the correction signal generator CG and each setting device MS, As may be a digital switch,
It is also possible to use a strap terminal or the like, and it is also possible to store this information in a memory or the like in advance.

In addition, the main function of the control unit CNT is
Next to TART', 1. Initial processing to set the initial state of each part 11. 1. Measurement processing such as inputting the count value of counter CUT and storing it in memory, and transmitting the measurement data in response to the request from the central station. There are three types of transmission processing.

FIG. 4 is a flowchart showing the details of the ``measurement process.'' First, a signal is applied to the reset terminal R of the counter CUT to perform 1 counter clear, and then a signal is applied to the inhibit terminal IN) of the counter CUT. The signal is extinguished, 1 counter start is performed, and whether or not the reference time determined according to the oscillation frequency has elapsed is determined based on 1 reference time elapsed? If this becomes YES, the inhibit terminal is set. A signal is given to INH to cause it to perform one counter stop.

Regarding this, it is necessary to import one count value, and the counter C
For example, take in the lower 12 bits of the UT's count output,
Furthermore, during the count output of the counter CUT, for example, check the upper 4 bits, and check whether the upper 4 bits are counted or not. If the count value is abnormal in 〃, the answer is No, and it is assumed that the actual measured value exceeds the measurement range, and it is determined that lunge over l has occurred.

- Upper 4 bit count? If the count value is normal and fi YES in 〃, then by the above-mentioned 1 correction operation by addition or subtraction〃, the count value imported by turtle count value import I is corrected by the correction value, and then
Convert the count value to temperature T by a predetermined calculation, and if the result is YES for N-50°C, then convert it to temperature T.
``150℃>T'' to determine whether the actual measured value is within the measurement range.

In addition, air-50C<T tt> x heat-A150℃) 7
If the answer is NO, the process moves to over range.

FIG. 5 is a flowchart showing the details of the transmission process. First, the data obtained in FIG. When the signal is received, the code is determined to indicate 'Polling signal? If the answer is YES, check whether the address set by the address setter As and the address indicated by the polling signal match. 〃After comparison, this is Y
If it is ES, after making whisper transmission preparations, send the contents of the transmission register to the transmission circuit SR and transmit one data.
Then, 'Sending completed?' According to YES,
Finish sending data.

In addition to using the crystal oscillator If the span in the electrical output of the physical quantity detection element is not constant, the span may be made constant in the measurement circuit.

Further, the fourth N correction calculation may not be performed at the sensor, but may be performed at the solid device side, and the line L2. The present invention can be freely modified in various ways, such as using a two-wire transmission path for power supply by L3, phantom power supply, or using a separate power supply.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, a measurement output having a predetermined span and zero position can be obtained only by adjusting the zero position using a correction signal generator, which simplifies the adjustment effort. It exhibits remarkable effects in sensors for various applications.

[Brief Description of the Drawings] Fig. 1 is a diagram showing the relationship between physical quantities and measurement outputs, Fig. 2 is a block diagram showing an embodiment of the present invention, and Fig. 3 is a circuit showing a specific example of a correction signal generator. Figure 4 shows "Measurement processing"
FIG. 5 is a flowchart showing details of one transmission process. X...Crystal oscillator (physical quantity detection element), O20...
・・Oscillation circuit, CUT ・・Counter, CNT
@...Transmission circuit, CG...Φ/correction signal generator, DI
-1) s...Fist diode, R1-R5...Resistor. Patent applicant Yamatake Honeywell Co., Ltd. Agent Masaki Yamakawa (#υ11 people) Figure 1 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] a measurement circuit that processes the electrical output of the physical quantity detection element and sends out a constant span of output in response to a change in the physical quantity;
One point characterized by comprising a correction signal generator that sends out a correction signal for correcting the zero position of the measurement output, and a calculation section that performs calculations based on the correction signal on the output of the measurement circuit to obtain the measurement output. Adjustment sensor 0