DE3433760A1 - Microelectronic measured data acquisition system - Google Patents

Abstract

The invention relates to a microelectronic measured data acquisition system for the connection of sensors and for the relaying of measured information to a computer. The invention consists in that the system comprises one or more identical subsystems each having a finite number of measuring channels, it being possible for the subsystems to be cascaded, ie. connected one behind the other, in any number, that the subsystem or any number of subsystems is/are connected via a single V 24 interface at a subsystem to be randomly selected to a compatible computer or terminal and that each and any sensor, provided with an assigned specific interface, is connected by means of a uniform, and therefore interchangeable, connecting cable with standard plug connectors at both ends to one of the measuring channels of a subsystem.

Description

Microelectronic data acquisition system

The invention relates to a microelectronic measurement data acquisition system according to the preamble of claim 1.

It is already known to convert physical measurement data into electrical quantities to convert, to digitize, to temporarily store in case of need and to use standardized To transmit interfaces to computers for further processing. So there are devices built for a physical measured variable and with a computer interface are provided. This means that a physical measured variable is entered directly as a number in the computer transferable. Another group of devices is based on the type of electrical quantity aligned into which the physical quantities are converted (e.g. strain gauges, Thermocouple, PT-1OQ). Here the sensor must be connected to the system, possibly calibrated and the data processed before they are transferred to the computer will. Ver supply voltages for the sensors are determined by the System delivered. Another group of devices deals exclusively with analog-digital conversion an electrical quantity to transfer it to the computer. Here is one Supply of the sensor and a calibration as well as processing of the measurement signal mostly required outside the device.

In the area of data acquisition and processing, however, mostly several different physical measurands are required at the same time. Both The devices described above, the device costs necessary for this increase approximately TO-proportionally with the number of different physical quantities to be measured and still additionally with the number of measuring points on the one hand, and on the other hand the measurement setup and partly also the operation only by one experienced in measuring technology and Elektror; 4k rersona mnglicn. DG wrc. dlo measurement data acquisition again and again on the current problem position tailored and cannot be transferred to any other task. This always requires problem-dependent specific measurement setups and thus high costs and inflexible data acquisition. In addition, each user must be aware of the specific Measuring task are incorporated and there is a detailed documentation in each case the sensor connections etc. required.

The task is therefore to develop a microelectronic measurement data acquisition system for connecting sensors and for forwarding measurement information to a computer to create both the adaptation and processing of a wide variety of physical Measured variables on a computer even for those inexperienced in measurement technology and electronics User enables as well as the time for a measurement setup to be kept to a minimum. Farther the measurement setup should be simple and the same for any task Structure.

A one-time familiarization with the measurement data acquisition system should sufficient for any measurement problem. The expandability of the measurement data acquisition system with identical system components to a large number of measuring points is to be provided. The unmistakability of the measuring point and the physical unit for the data which are taken over by the computer should be guaranteed even if various leads to the measuring points have been swapped.

The object is achieved according to the invention by what is stated in the claims specified measures resolved.

The invention is illustrated below using an exemplary embodiment explained in more detail by drawings.

In Fio. 1 the measurement data acquisition system is shown schematically, in Fig. 2 a measuring channel.

The measurement data acquisition system according to the invention consists of one Computer 1 and several sub-systems, div each one basic unit 2 and several measuring channels 3 included. The connection between the computer 1 and the basic devices 2 forms a serial or parallel interface. The measuring channels 3 each consist of one Sensor 4 and an adapter 5, which are connected via a sensor-specific interface are. The connection to the basic device 2 is made via a standard cable and plug a unified interface.

The measurement data acquisition system consists of one or more basic devices which can be cascaded as required.

The basic devices are provided with adjustable identifiers (e.g. numbers) and in this way can be distinguished from the computer or terminal. At a standardized RS-232C or V-24 Several basic devices can interface operate.

With an additional communication line between the basic devices it is guaranteed that only one basic device sends to the computer at a time.

Each basic device has equivalent plug connections to which the Sensor adapter can be connected to the sensors. The basic device detects over two serial communication lines: the sensor type or the sensor number and switches then enter the corresponding supply voltages and currents. It gets on this way information about the calibration variable of the sensor signal to be used Evaluation algorithm and the physical unit.

Each basic system consists of a complete process computer a communication interface to other computers and a measured value memory larger than 2 KB CMOS-RAM, its own A / D converter with measuring amplifier and multiplexer for reading in analog voltages, a counter for measuring frequencies, period duration and pulse widths, a D / A converter for outputting voltages and constant currents, a hardware clock with year, month, day, hours, minutes, seconds and an alarm time memory, an accumulator to supply the hardware clock and to save the memory inh old if the external power supply fails, a switching power supply for all required Voltages, also for the sensor supply, for voltages greater than 8 volts, one Extension plug for expanding the computer part (e.g. 1 MB CMOS RAM memory, 60 MB tape memory, printer connection, etc.) and a digital part for reading in the Identifier.

A measuring channel consists of the connection to the basic system, the data line, the sensor adapter and the sensor, whereby the sensor is either integrated in the sensor adapter is or through a sensor-specific cable is connected to it.

A sensor adapter consists of a digital part for switching on the Power supply of the sensor, for outputting the identifier and the sensor-specific Data such as correction and adjustment values, type of data transmission, the unit, Significance of the measured value, type of sensor supply (e.g.

Constant current) and the analog part for processing and amplifying the Measurement signal.

With a PT 100 temperature sensor, for example, after the detection the sensor type supplies the sensor with a constant current from the basic device. The occurring The voltage difference is tapped potential-free and with high resistance at the PT 100, and is amplified and transferred to the basic device with low resistance.

In the case of a thermocouple, the thermal voltage increases with the voltage of the Compensation point compared and occurring thermal voltages at the connection points are compensated. The voltage difference is transmitted.

In the case of an alpha meter for measuring the a-radiation, the in the counter tube A-radiation that hits it is amplified and added up in a counter. The counter will Read out digitally and serially at certain intervals and reset if necessary.

The procedure for acquiring measured values comprises the following steps: 1. Determination of the channel in the basic system, switching on the sensor supply, 2, reading the identifier and the sensor data, if new (the identifier results in the further Procedure), 3. Setting the sensor supply, 4. Selecting and starting the Conversion principle, 5. Reading in the measured value, switching off the sensor and the sensor supply, 6. Editing of the measured value (correcting, converting, interpolating), 7. Saving with ID, time and date, 8. Output of the value on a terminal or a printer, 9th end, next channel.

The procedure for reading in the identifier includes the following steps: - Selecting the sensor adapter by selection; - Use of the bidirectional Data line to and from the sensor; - Synchronization of the data traffic through the clock line.

The measurement data acquisition system is said to have a low power consumption long periods of time independent of the mains with standard 12 volt batteries or solar cells can be operated. The system should be waterproof and dustproof as well as mechanically can be built robustly and can therefore be used in harsh environments as well as under outdoor weather conditions can be used. All commonly used voltage and power supplies are integrated in the basic device. Analog as well as digital measurement signals such as frequencies or pulse times are recorded on each measuring channel. The sensors can do one Have a distance of up to 30 m from the basic device. With a special extension cable with adapter can be the distance can be enlarged up to 1000 m.

Every new sensor with adapter added to the sales program can can be recognized by basic devices that were delivered before this point in time, whereby new physical units of the sensor are also communicated to the basic device by the sensor adapter will. In the basic device, a data reduction (e.g. threshold value acquisition, minimum Maximum measurement, etc.) as well as a preliminary evaluation (e.g. statistics) or link of measurement data.

The advantages of the microelectronic measurement data acquisition system according to of the invention are that due to the structure of the measuring system in side by side Basic devices when expanding the measuring task an expansion of the system with identical Green areas and sensor modules are possible.

Any physical quantities can be programmed in any Order to be measured.

The user needs to be concerned with the sensor installation and the supply voltages not to worry of sensors.

Due to the robust, watertight construction, the data acquisition is in the rough Operation and under external weather conditions possible. By identifying the sensors incorrect assignment of the measurement data is excluded.

Due to the re-verification capability of the sensors and the filing of the verification parameters The calibrated sensor in the sensor module can be used on any basic device will. The watertightness is fully guaranteed during the calibration process.

Preprocessing the measured values relieves the buffer memory and the connected computer possible. Through programmable measurement data recording Autonomous data acquisition is also possible without a computer connection.

Claims (9)

Claims 9 microelectronic measurement data acquisition system for Connection of sensors and for the transfer of measurement information to a computer, characterized in that the system consists of one or more identical subsystems each with a finite number of measuring channels, the subsystems in any Number can be cascaded, i.e. connected in series. 2. Microelectronic measurement data acquisition system according to claim 1, characterized in that the subsystem or any number of subsystems via a single V 24 interface on an arbitrarily selected subsystem is connected to a compatible computer or terminal. 3. Microelectronic measurement data acquisition system according to the claims 1 and 2, characterized in that each any sensor with provided with an assigned specific interface, via a uniform and therefore interchangeable connection cable with standard plug connections at both ends is connected to one of the measuring channels of a subsystem. 4. Microelectronic measurement data acquisition system according to the claims 1 to 3, characterized in that a subsystem each sensor independently of its Assignment to a channel identified with regard to the physical quantity to be measured and transmits both the measured value and the unit to the computer. 5. Microelectronic measurement data acquisition system according to the claims 1 to 4, characterized in that a subsystem has a program-controlled energy supply for the various possible connected sensors on a 12 V basis. 6. Microelectronic measurement data acquisition system according to the claims 1 to 5, characterized in that the system consisting of the entirety of the Subsystems that can be operated via a 12 V accumulator. 7. Microelectronic measurement data acquisition system according to the claims 1 to 6, characterized in that a subsystem as an encapsulated flat box is formed, the top of which contains the connectors. 8. Microelectronic measurement data acquisition system according to the claims 1 to 7, characterized in that a subsystem on its own with a waterproof Sheath can be provided with appropriately sealed bushings for the cables can. 9. Microelectronic measurement data acquisition system according to the claims 1 to 8, characterized in that a subsystem is freely programmable with regard to the course of the measurement processes as well as the preprocessing of the measurement data.