DE3743847A1 - Process data capture and processing system - Google Patents

Abstract

The system for capture and processing of several physical quantities of a physical process is constructed modularly (measurement modules) on the measurement data capture side (sensor side), and hierarchically on the processing side. Several measurement modules, which are each assigned to a partial process, are connected to a central computer via a measurement bus. The measurement bus is an extended microprocessor bus of the central computer, and is in the form of a standardised microprocessor bus (SMP-BUS). The central computers of the total process communicate with each other, and with a higher-level host computer, via a dedicated, serial bus system. The measurement modules contain all the components which are necessary for capturing measurement data, and an interface to the SMP-bus, via which they can be addressed using an address which can be set in the measurement module. The data on the SMP-bus is in a normalised floating-point format. The system also includes a calibration system for the measurement modules.

Description

For the metrological acquisition of a large number of physical quantities of a Process are often computer-controlled process measurement data acquisition and -Processing systems used, which output signals from transducers, the the acquisition of the physical quantities and their conversion into equivalents electrical quantities are used, converted into computer-compatible numerical values and these process accordingly.

In addition to systems with central processing of the recorded data and over Multiplexers and analog / digital converters connected to the transducers systems on the measurement data acquisition side have only been enforced for a while (Sensor side) modular (measuring modules) and hierarchical on the processing side are established, enforced. The transducers are part of the measurement modules (sensors) that already have microcomputers for preprocessing data contain. Several measuring modules are each connected to a processor via a bus system processing and control computer (central computer) connected to the process of a Controls the measuring program and processes the preprocessed data.

For larger processes or processes that have a larger spatial expansion have, the measuring modules are each combined into groups and over group-specific bus systems each assigned to their own central computer connected. These in turn have their own (mostly serial) bus stem with a coordination computer (control or host computer) and possibly with connected to each other. Such hierarchically tiered computer systems and Pro ZEßdatenerfassungssysteme are for example the book "Rembold, U./Armbruster, K./Ülsmann: Interface technology for process and microcomputers, 1981, Oldenburg-Verlag ", to be found.

However, bus systems used to date often have relatively low data rates as well as a data processing structure which real-time processing of data only allowed with slow physical processes. For For the sensors, on the other hand, faster processes had to have computers with higher lei or it had to be used with inflexible hardware be worked, whereby the adaptability of the measurement data acquisition system the metrological task was limited and slowed down. Not least does this affect the cost structure of the overall system.

The inflexibility of such known process measurement data acquisition systems sets even further down to the calibration of such sensors. That's the way it is Common in known systems, in the event of failure of a single measuring channel on Re serves to evade systems or to recalibrate the entire system on site have to; the latter is unavoidable when the entire system comes to a standstill tied together.

In this context, it is already known to transfer calibration data of a sensor in its processing unit or a memory belonging to it for correcting the structure of the recorded measured values. During the calibration, the old data are always overwritten so that the new data is available for correction place. To have a control for the long-term behavior of a transducer additional databases must be kept (e.g. in the form of Lists) in which the calibration "history" of the transducer is recorded.

The invention is based on the object of a process measurement data acquisition and -Processing system to create, which is simple and inexpensive to build and is highly flexible, has short set-up times and a high Data throughput guaranteed.

The task is through the characterizing features of claim 1 and the independent ancillary claims solved. Further, the invention in more advantageous Features that design wisely are contained in the subclaims.

The advantages of the invention are primarily to be seen in the fact that a Pro measuring data acquisition and processing system was created that quickly and is easier to configure (adaptable to different measuring tasks), a high data throughput guaranteed and inexpensive to create and is entertaining.

The system has short set-up times and guarantees due to its good calibration properties minimal downtime. It enables one To save the calibration history in the sensors (measuring modules) so that especially a trend analysis of the aging behavior of a transducer carried out and for an exchange that may become necessary can be pointed out. The computer-controlled one used for this purpose The calibration system allows a largely automated calibration process.

The invention will be illustrated by the examples shown in the drawings explained here. It shows

Fig. 1 is a Prozeßmeßdatenerfassungs- and processing system,

Fig. 2 shows a mechanical structure of the system,

Fig. 3 shows a measuring module according to the prior art,

Fig. 4 shows a measuring module according to the invention,

Fig. 5 shows a measuring module according to Fig. 4, however, with advanced processing, configuration and calibration

Fig. 6 is an output measurement module,

Fig. 7 shows a central computer,

Fig. 8 is a central computer of FIG. 6, but with an extended function and processing capacity,

Fig. 9 is a flowchart of a main program for a central computer,

Fig. 10 is a flowchart of FIG. 9, but for a subroutine for module initialization

11 is a flowchart of FIG. 10, but routine. For a measurement value capturing,

Figure 12 shows a calibration system.

In Fig. 1, 1 is a process measurement data acquisition and processing system for the acquisition of several physical process variables mp.ÿ (i = 1, 2, ... L; j = 1, 2 ..., K) one in sub-processes 2. i subdivided, physical process. The physical process variables mp.ÿ are each recorded via sensors (measuring modules) 3. ÿ and preprocessed as data words via Bausysteme mb.i (measuring bus) to the central computer 4. i or are queried by this.

The central computer 4, i in this case serve assurance processing, compression and SpeI of mp.ÿ as data words of the measuring modules 3. ÿ unreacted process variables, as well as the controller or the loading control programs into the measuring modules 3. Y and for coordinating the data traffic on the measuring buses mb.i. Finally, the central computer 4. i can also be connected to one another and / or to a coordination computer (host computer) 6 via a serial bus system 5 , which coordinates the tasks of the process measurement data acquisition and processing system 1 as well as the data input and output and the mass storage of Data and programs (these I / O modules are not shown for reasons of clarity).

Practically any computer (from the personal computer to forward), provided that it has a suitable, standardized Interface, e.g. B. a serial interface or HDLC interface, etc. disposes.

In physical processes of smaller spatial extent or lesser numbers to be detected process variables, the system 1 also only of one central computer 4.1 and its associated measuring modules 3.1 j exist, wherein the input output devices can be connected then directly with the central computer 4.1 /; this system can also be used as a mobile data acquisition system for moving processes (for example for test drives of motor vehicles). For this purpose, it is accommodated in a further slide-in system described below in Fig. 2 and expanded with a manual input device, a display for displaying program steps and measured values and a mass memory for measured values and measuring programs with an additional external interface for loading measuring programs and reading out measured data ( Not shown). Of course, several process parameters can be detected by a measuring module 3. ÿ, provided that they are equipped respectively with a plurality of measuring channels.

In process data acquisition systems of this type, a serial bus system or the so-called IEC bus is usually used as the measuring bus mb. Although these bus systems are internationally standardized, especially as far as the IEC bus is concerned, they are relatively inflexible and only allow low data transmission rates, so that their usability on so-called "slow" processes, e.g. B. in the chemical industry is limited. Predetermined bus protocols for the formation of the data traffic limit the flexibility of these systems and also require high processing power and corresponding processors on the measuring modules. Such known systems are overwhelmed in particular for "fast" processes in which many measured values have to be measured with a high acquisition rate.

According to the invention, the bus system mb.i is now an expanded (micro) processor bus of the central computer 4. i , onto which the measuring modules 3. ÿ can be switched or plugged in, or which the measuring modules 3. ÿ with the central computer 4. i connecting bus system mb.i is a standardized, parallel microprocessor bus (SMP bus), for example from Siemens, and the measuring modules 3. ÿ and central computer 4.1 are built with SMP-compatible modules. Data traffic between measuring modules 3. ÿ and central computer 4. i is handled in a standardized floating point format into which the measuring modules 3. ÿ convert the recorded, converted and processed measured values.

This makes it possible to have a process measurement data acquisition and processing system with largely uniform, simple and inexpensive to build permanent measurement modules with which a measurement data acquisition with a high Data rate can be carried out. The data in floating point format can also be processed in the central computer without any further data conversion be worked on.

The result is - besides the high data acquisition rate - high flexibility of the overall system, as a part of process 2. i and a central computer i assigned measuring modules of Meßwertaufgabe can used to tare any confi 4. 4. ÿ accordingly.

Fig. 2 shows the metrological structure of a partial process 2. i associated process measurement data system with a known slide-in system (19 '' - system, rack) 7 , from a preferably metallic base frame or housing 8 , inserted into the slide 9 and screwed to this can be (not shown).

When plugged in, the drawers 9 are connected to lines 10, 11, 12 of the SMP bus mb and lines 13 of a power supply 14 , which is also plugged into the drawer system and supplied via the lines 13, the drawers with operating current.

Finally, the central computer 4.1 and the measuring modules 3.1 j are plugged into any configuration on the SMP bus 10 to 12 and the power supply line 13; Here, for example, two measuring modules for detecting pressures 3.11 and 3.12 measuring modules for detecting temperatures 3:13 to 3:16, a measuring module for detecting digital signals 3.17 a measuring module for detecting the relative air humidity 3. 18 and a measuring module for the acquisition of analog voltage or current signals 3.19 . The maximum number of measuring modules attachable j is here only by the maximum bus length of SMP bus or by the influence thereof installation space of the measuring modules in the bay 3.1 is limited system.

The largely optional equipping of the slide-in system results good flexibility (i.e. adaptability to the measurement task) of the system and easy interchangeability of defective or imprecise (to be calibrated) measurements inserts.

The central computer 4.1 can also be connected to a host computer via connections not shown (serial type).

The structure of the components of the system will now be explained on the basis of the following Fi gures, with a sensor 15 of known philosophy to be brought into memory again by means of FIG. 3. Via a physical / electrical converter (transducer) 16 , the physical process variable m to be measured is converted into an equivalent electrical signal me . This is amplified and filtered by means of an analog circuit 17 (analog signal ma) . The analog signal is converted via an analog / digital (A / D) converter 18 into a digital signal md , which can be detected by a microcomputer 19 and processed further.

The microcomputer 18 corrects the data word derived from the digital signal on the basis of correction values stored in an internal or (not shown) external memory for non-linearities, gain and zero point errors of the upstream arrangement 16 to 18 and outputs the corrected measured value if necessary or on request via a Bus coupler 20 on the bus system (e.g. IEC bus). Of course, in the case of a sensor for detecting digital signals, the analog switch 17 and the A / D converter 18 should be replaced by a signal or pulse processing circuit.

In Fig. 4 there is shown a measuring module 3 according to the invention. The representation of the power supply and coupling elements for connecting the measuring module to the SMP bus system has been omitted for reasons of clarity. The measuring module 3 comprises several physical / electrical converters (transducers) 21.1 to 21. n , which the physical measured variables mp. 1 to mp.n in equivalent electrical signals me. 1 to implement me.n. A controllable Speisespannungs- or -stromteil 22 serves to feed the pickup 21.1 to 21. n.

The electrical signals me. 1 to me.n are amplified by parameterizable amplifiers 23.1 to 23. n (amplified measuring signal mv. 1 to mv.n) , processed by means of controllable filters 24.1 to 24. n (filtered measuring signal mf. 1 to mf.n) and an analog multiplexer 25 supplied. The multiplex signal ma is again amplified by means of a further parameterizable amplifier 26 (amplified multiplex signal mav) and sampled by means of a sample-and-hold circuit 27 (sample- and-hold signal mash) and for analog-digital conversion (analog / digital signal md) by means of an A / D converter 28 cached. The digital signal md is a device 29 for galvanic separation (via optocoupler or isolating transformers), the measurement information supplied thereof outgoing mi a microcomputer 30, which also switches control information sti of the electrical isolation 29 on a control bus 31st The control signals stb on the control bus 31 control the supply voltage or current part 22 , the amplifiers 32.1 to 23. n , the filters 24.1 to 24. n , the multiplexer 25 , the amplifier 26 , the sample and hold circuit 27 and the A / D converter 28 . This controllability of the elements 22 to 28 permits in particular a highly uniform, largely independent of the type of recording structure of the measuring modules and an easy interchangeability of the transducers 21.1 to 21. n in the case where a sensor of a type or manufacturer by another type or manufacturer with different transducer data is to be replaced, so that, for example, other gain factors, zero points, filter curves and filter application points must be set.

The microcomputer 30 receives the measurement information MI on, sets it in (raw) measurement data to, adjusted these, etc. (ie conversion characteristics, which are caused by the upstream measuring arrangement 21 to 28 of nonlinearities, gain and zero point errors, dynamic errors, temperature transitions ), based on a non-volatile memory module (EPROM, EEPROM) stored in a microcomputer 30 , converts it into a uniform, standardized floating point format and stores it for retrieval by the central computer 4 in a memory module with random access (RAM) which is also integrated in the microcomputer ) between. The acquisition rate of the measured values is fixed in the microcomputer 30 and can be changed (by program) by the central computer.

Some special features result from the bus concept used in the measuring bus mb (SMP bus system). The microcomputer is a microcomputer (slave processor, for example of the 8742 type) subordinate to the central computer 4 on the bus system mb ; the central computer 4 therefore takes over the control of the bus traffic.

To query measured values or to enter control programs, the central computer 4 addresses the measuring module or the microcomputer 30 - like a conventional peripheral module - via an address which it places on the address bus a of the measuring bus mb for this purpose. The address is decoded by means of a so-called PAL module 32 (programmable array logic) and a wiring field 33 (wrap field) and the corresponding data traffic between the microcomputer 30 and the central computer 4 is initiated on the data bus d. Next to the wiring board 33, a Kodierschalterfeld 34 serves to free adjustability of the Meßmoduladresse within a Meßmoduladreßraumes.

A very simple and inexpensive microcomputer 30 can thus be used, which is reasonably utilized by its task (control of the measuring module, correction of the conversion properties, data conversion). The data traffic is very simple and the normalized (floating point) data are easily processed in the central computer.

The acquisition of the measured values takes place at fixed, defined by the control program cycles, the data to be made available for retrieval by the central computer 4 are stored in a certain memory area in the microcomputer 30; old measurement data are overwritten.

Fig. 5 finally shows a measuring module 3 ' with a higher processing power (or with a higher address data space) and greater flexibility in the parameterization (programming) of the measuring task, so that - if necessary - preprocessing or Pre-compression of the recorded, converted, corrected of conversion properties and converted into the normalized floating point format measurement information can take place. In this respect, the upstream actual measuring arrangement from the modules 21 to 28 is identical to the measuring module 3 according to FIG. 4. Likewise, a device for potential separation (at the same point as in FIG. 4) can be used, which has been omitted for reasons of clarity.

The control of the modules 21 to 28 and the measurement data processing is now divided between two microcomputers, the control bus stb being carried out by a control computer 35 (for example of the VPI 452 type). The control computer 35 receives control information and programs via a serial interface sbsV from a host computer 36 , for example of the 8096 type; This receives the digital signal and the measurement information from the A / D converter 28 via a serial / parallel converter 37 , which for this purpose is connected to the host computer 36 via a parallel processing bus vb , 38 (processing data bus vd , processing control bus vs , processing address bus va) .

Via the processing bus vb , 38 , the host computer can also access a volatile memory module with random access RAM 39 , at least part of which is battery-backed (not shown), and a non-volatile read-only memory module 40 (ROM, EPROM, EEPROM ..) access.

The coupling of the measuring module 3 ' or the processing processor 36 (via the processing bus vb , 38 ) to the measuring bus mb now takes place in a special way:

• - Between the processing data bus vb and data bus d of the measuring bus mb there is a so-called DUAL-PORT RAM module 41 , from which data can be read out or read in from both the processing bus vb and the measuring bus mb , completely independently of one another ; the block 41 therefore serves as a data buffer;
• Control information is exchanged from both sides (processing control bus vs and control bus s) via a wiring field 42 and a PAL module 43 ; the DUAL-PORT-RAM module 41 is also controlled from the wiring field 42.
• The host computer 36 can switch addresses directly onto the address bus of the measuring bus mb.
• The addressing of the DUAL-PORT-RAM module 41 takes place directly from the processing bus vb , from the measuring bus mb , as in the case of the measuring module 3, via a PAL module 44 and a wiring field 45 ; the addresses are set via a coding switch field 46 and the wiring field 45 .

By introducing the DUAL-PORT RAM module 41 , it is possible to temporarily store larger data sets so that "older" measurement information is not lost when the central computer is busy and cannot comply with its query cycle.

As a further special feature, the host computer 36 has a serial interface 47 (serial bus sb) , which can be contacted from the front in the measuring module insert. Via this serial bus sb the measuring module 3 ' can be configured at any time - in addition to being configurable via the measuring bus mb and the central computer 4 - that is, it can be loaded and / or calibrated with measuring programs, or a data connection to other modules, computers, etc. be created for data exchange.

In conclusion, it should be noted that the representation of other, for the operation of the components of the measuring module 3 ' required blocks such as clock, Koppelbau stones to the measuring bus mb , etc. has been omitted for the sake of clarity. These are already known to the person skilled in the art.

The measuring module 3 ' can also be equipped with a signal processor or expanded by one, which a measurement data acquisition and preprocessing with an even higher data rate for data acquisition in particularly time-critical processes such. B. Crash tests in automotive engineering, allowed; the signal processor can either replace at least one of the two computers 35, 36 (and itself be connected to the measuring bus) or supplement it.

Concerning the measurement modules, it should be noted that the physika Lisch / electrical converter also arranged outside of the measuring units, d. H., can be separated from these and with these via fiber optics or elec table lines can be connected.

In Fig. 6 is shown as an example of an output measuring module 3 '' a digital input / output module, which are plugged in the same way as the measuring modules 4, 4 ' on the measuring bus mb (within the plug-in system 7 of FIG. 2) can. The output measuring module 3 '' of this type can be used, for example, to control digital actuators such. B. solenoid valves or to detect feedback signals can be used.

A one-chip microcomputer (slave processor, for example of the 8742 type) is connected directly to the data bus d and to the control bus s and the address bus a via a wiring field 49 , as in the case of the measuring module 3 . A connected to the address bus A and to a serving for setting the output module address Kodierschalterfeld 15 PAL Bausten 51 serves to decode the data traffic to / from the host computer 4 abutting Eden address.

A port expansion module 53 of the type 8243 is connected via a bidirectional port 52 and can serve up to 8 outputs or inputs in any configuration via a first port 54 and a second port 55. These outputs are amplified by means of a first driver module 56 and a second driver module 57 of type 29828 and via a first and second module for galvanic isolation 58, 59 with optocouplers 60, 61 or relays 62, 63 to first and second sockets 64, 65 for connection the actuators and feedback (not shown) switched. The input signals pass from the sockets 64, 65 via optocouplers 66, 67 directly to the port expansion module 53 .

The output measuring module 3 '' can of course also be of an analog type (not shown). It then comprises essentially the same elements as a measuring module 3 , except that the output signal path runs in reverse order and a digital / analog converter is used instead of the analog / digital converter and the sample and hold module 27 and possibly the multiplexer 25 can be omitted.

The output measuring module 3 '' , like the measuring modules 3, 3 ', is addressed by the central computer 4 via an output measuring module address (address bus a) and can generate output signals based on information read in via the data bus d (e.g. on / off signals, clock rates, etc.) .) in order to influence process-controlling variables directly or via electro-physical converters. The process measurement data acquisition and processing system can be expanded in this way in extreme cases up to the process control and regulation system.

The data traffic on the data bus d runs here again in the standardized floating point format, provided that it is not just purely digital control commands. The microcomputer 48 can control the electro-physical converters in such a way that their static and dynamic conversion properties are balanced. In the case of analog output measuring modules, these can also have a measured value recording part such as the measuring modules 3, 3 ' and be provided with control loops.

Fig. 7 shows an example of a host computer 4 which controls the traffic on the Meßbus that of the measuring modules 3, 3 'collected measured values (data words in normalized floating point format) processed further, caches and sbh via the serial bus system 5 to the host computer 6 or an output medium. Likewise, the measuring modules are configured by the central computer 4 , that is, loaded with measuring programs and the output measuring modules 3 '' controlled. The central computer 4 comprises a microprocessor 68 of the type 8031, 8051, 8751 or 80186, which is directly connected to the control bus of the measuring bus mb (input / output 69 ) and also directly covers part of the address space of the measuring bus mb (input / output 70 ). . The remaining address and data traffic is handled via an input / output 71 of the microprocessor 68 , the address traffic taking place via a memory flip-flop 72 , for example of the 74LS373 type, with the address bus a of the measuring bus mb and the data traffic via a bus driver 73 (74LS245) with the data bus d of the measuring bus mb . The measuring bus mb is thus the expanded microprocessor bus of the microprocessor 68 (SMP module). A volatile memory with random access (RAM) 74 and a programmable, non-volatile (EPROM) or battery-buffered, volatile module 75 with random access (RAM), which with their control and address line directly to the measuring bus mb and to the data lines, serve as memory modules are at the output 71 of the microprocessor 68 .

A central computer 4 ' with extended processing capacity or extended address / data space is shown in FIG. 8. It comprises a microprocessor 76 of the type 80186, which is located with its control input / output 77 via a bus driver module 78 of the type 82188 on the control bus of the measuring bus mb and with a parallel input / output 79 via a bus transmitter / receiver module 80 (2 are used for 16 bit data) of type 74LS645 to data bus d and via memory flip-flops 81 of type 74LS 373 to the address bus a can be placed, with the internal bus system sbi of the central computer 4 ' (in internal control bus si , internal data bus di and internal address bus ai) via buffer modules 82, 83 of the type 74LS 240/244 or bus transmitter / Receiver modules 84 are decoupled from the measuring bus mb (extended microprocessor bus).

A mathematical compressor 85 of the 8087 type is connected to the output 79 of the microprocessor 76 and to the internal control bus si to accelerate calculation processes. Finally, memory modules 86 (RAM) or 87 (ROM, PROM, EPROM, EEPROM, battery-buffered RAM), as well as a serial data communication module 88 , for example of type 8274 for data traffic via a serial bus system sbh ' ( 5 ), are attached to the internal bus system sbi. connected to the host computer 6 . Instead of the communication processor 88 or in addition to it, an HDLC processor can also be connected to the internal data bus via optical fibers for faster, serial data traffic to the host computer 6.

In Fig. 8, a main program for a central computer 4, 4 'is described. After a system start or a reset 89 , an initialization 90 of the microcomputer 68, 76 of the central computer 4, 4 'takes place (resetting of the computer in a defined basic state). A so-called "limit value file" is initialized, 91 ; this is a program part, not described in detail, for monitoring limit values of individual analog and / or digital process variables or of functions of several process variables. If process variables or functions exceed their limit values, the central computer 44 sends a rapid interrupt to the host computer, which then initiates appropriate measures.

The measuring modules are then reset, 92 and a first subroutine 93 for measuring module initialization called, which will be explained in more detail later with reference to FIG. After a mark A has been passed , a second subroutine 94 is run through with a measured value acquisition routine and it is queried 95 whether a parameterization command from the host computer 6 is present; If the query 95 is positive, a new data acquisition program is transferred from the host computer 6 to the central computer 4, 4 ' , whereupon the central computer 4, 4', the measuring modules 3, 3 ' and output measuring modules 3'' only parameterized, that is, with measuring programs or Control programs loads; this is done by means of a subroutine "parameterization routine" 96 , which does not need to be specified in more detail. Finally, as in the case of a negative query 95, a branch is made back to label A.

The first subroutine 93 “module initialization” is shown in FIG . After program start 97 , a (measuring) module address is first set to the lowest value of a module address range, 98 , and after passing a mark B the measuring modules 3, 3 ' , and output measuring modules 3''are initialized by means of a program loop by an initialization command and the current module address is switched to the measuring bus, 99 and the measuring module address is increased by 1 until the measuring module address range is exceeded (query 100 ), 101 and the label B returned.

The module address is then set back to the lowest value of the module address range, 102 and, after passing a mark C, a module status is queried 103 . This means that it is queried whether a measuring module 3, 3 ' or output measuring module 3''is plugged onto the measuring bus mb whose module address (set by means of the coding switch field 34, 46, 50 ) matches the output module address; this is done by connecting the current modular address and a status query to the measuring bus.

If no measuring module with this address is plugged in, a branch is made to a label D ; on the other hand , if query 103 is positive, the central computer 4, 4 ' requests a module data from the measuring module 3, 3' or output module 3 '' , which specifies a number of measuring channels (ie how many measuring inputs are applied) or output channels, 104 . The module address and number of channels are then created in a channel table, 105 , and after the mark D has been passed, the module address is increased by 1, 106 and you are asked 107 whether the module address range has already been exceeded; If not, the program branches back to label C , if so, the subroutine is terminated, 108 and a return is made to the calling program.

Finally, FIG. 11 shows the second subroutine 94 of the measurement acquisition routine. After the program start 109 , first count indices U and V are set to zero (lowest value of the channel table, where the module address is stored under U and the number of channels under V ), 110 . After passing a label E , the module address is set to the channel table value corresponding to U , 111 . It is then queried 112 whether the module address is outside the measuring module address range (here, for example, between 0 and 255); if yes, no measuring module is addressed and the program branches to the end of the program 113 via a label F ; if no, the number of channels is set to the channel table value corresponding to V , 114 .

After passing a mark G , it is queried whether the number of channels is equal to zero, 115 (the plugged-in measuring module is not required for measurement); if this is the case, the indices U, V are increased by 1, 116 and branched back to label E , if this is not the case, the module address and a command "read measured value" are output on the measuring bus, 117 and a so-called " Time-out counter "started, 118 .

After passing a mark H , a query is made as to whether the module status is equal to one, 119 ; if not, there is a query 120 as to whether the time-out counter has reached its end value. If the query 120 is negative, it branches back to the mark H , so that the central computer 4, 4 'can continue to wait for a module status response from the addressed measuring module 3, 3'; If, on the other hand, query 120 is positive, a subroutine “error routine” 121 (not described in more detail) is called and the program progresses to the end of the program 113 via label F. The subroutine 121 starts certain diagnostic processes and, if necessary, initiates a display on the host computer system.

If, on the other hand, the query 119 is positive, a data byte is read out from the data memory of the addressed measuring module 3, 3 ' and stored in the central computer 4, 4' , 122 . It is then queried whether an entire data record that belongs together (here: for example four data bytes per measured value) has already been read, 123 ; if no, the system branches back to label H , if so, the number of channels is reduced by one, 124 , and a return is made to label G in order to query the (measured value) data record of the next channel of the same measurement module.

Fig. 12 finally shows a calibration system 125 for measuring modules 3 and 3 ' . The main components are:

• - an IEC-bus-compatible calibration computer 126 for controlling a calibration process of the entire calibration system 125 via an IEC-bus 127 ,
• an input device 128 and a display unit 129 (screen),
• a calibration source device 130 for providing precisely quantified, physical calibration variables pkg (calibration standards),
• - a climatic cabinet 131 for controlling the temperature of physical / electrical converters ( sensor 21 ) or for determining the influence of temperature on the measuring devices,
• - a calibration slide-in system 132 ,
• a plotter 133 for outputting calibration data or calibration curves and measured values in tolerance band representation and a plotter 134 .

The calibration source device 130 , like the other components 131 to 134, is connected to the IEC bus. It has a plurality of electro-physical converters 135.1 to 135. y which, upon input of electrical setpoint values (in the form of data from the calibration computer 126 ), precisely defined and quantified physical calibration variables pkg. 1 to pkg.y to act on the measuring inputs or the electrophysical transducer of the measuring modules 3 and 3 ' emits. These are, for example, pressure sources, temperature sources or sinks, current sources, voltage sources, etc.

The Kalibriereinschubsystem 132 is constructed mechanically similar as the slide system 7 for measuring modules of Prozeßmeßdatenerfassungssystem according to Fig. 2. It merely next lines for the power supply (not shown), the address bus a, 136, the data bus d, 137 and the control bus s, 138 of the measuring bus mb additional connection lines 139 for providing programming voltages ps for the EPROMS on the microcomputer 30 of the measuring module 3 . The calibration plug-in system 132 is also equipped with a converter 140 for converting the IEC bus signals into SMP bus-compatible signals and with a programming voltage generator 141 and a coupling module 142 for connecting the measuring modules 3 and 3 ' to the calibration system 125 .

The measuring modules 3 ' , however, do not require any programming voltage, since the calibration data are stored in these measuring modules in a battery-buffered RAM; for calibration or for the exchange of calibration data, they are connected to the calibration computer 126 via the serial bus system sb.

The modular structure of the process data acquisition system and the structure of the calibration system 125 allow

• - Process data acquisition system and calibration system spatially from one another separate,
• - To calibrate measuring modules individually, that is, in the case of an incorrectly measuring or routinely calibrated measuring plug-in unit, the entire process data acquisition system does not have to be shut down and a calibration device must be brought to the system, but the corresponding measuring module is removed from the plug-in system 7 and recalibrated in the calibration system and then re-inserted the plug-in system 7 is used or replaced by a reserve measuring module of the same type, the address of the measuring module 3, 3 ' being set accordingly in the coding switch field 34 of the reserve module and the measuring module being configured from the central computer 4 according to the measuring task,
• - the process data acquisition system by keeping replacement measuring modules ready to be able to operate with minimal downtime, with for several measuring modules of the same type, only a replacement measuring module is required.

During an initial calibration, a calibration process now runs in the following way away:

• - After inserting the measuring module or the measuring modules 3, 3 ' into the calibration slide-in system, the physical-electrical converters 21 of the measuring modules 3, 3' are acted upon with physical calibration variables pkg of variable values. Since no correction data are stored in the correction data storage area of the measuring modules during an initial calibration, the measuring module transfers uncorrected measuring data to the measuring bus. These uncorrected measurement data are compared with nominal data in the calibration computer 126.
• - In a second phase, the calibration computer calculates correction data for Adjustment of the conversion properties of all components of the measuring module, such as B. gain, zero point errors, static and dynamic errors and Non-linearities, temperature responses etc. and writes the correction data in the correction data storage area.
• In a third phase, the physical transducers 21 of the measuring modules are again acted upon with calibration variables of variable values. The measuring module now switches the recorded, corrected measured data converted into normalized floating point format to the measuring bus mb. The calibration computer compares these again with nominal data so that the calibration can be repeated if necessary if a predetermined tolerance band is exceeded.

A second or further calibration (recalibration) runs as follows from: After applying the calibration standards and the comparison to the measuring modules the recorded data with the target data, if this is not sufficient must be respected, one at the beginning of a record with the current Address indicating calibration data updated (increased). This new data sentence is not available, so that the measuring module after exposure return uncorrected values with calibration standards; the further process of Calibration (second and third phase) then runs like the first calibration away.

Writing the correction data into always new ones during recalibration Memory areas has compared to the known overwriting of the old Korrek turdata set has two major advantages:

• - First of all, there are no special "switching signals" between Calibration computer and measuring module are exchanged, since the measuring module in a missing correction data record in the one indicated by the start address Memory area automatically outputs uncorrected measurement data.
• - Secondly, the "old" calibration data records from the calibration computer can each currently read out and thus the aging behavior of the transducers (or the Measuring arrangement) can be determined by trend analysis. This can be considered wich This is a useful tool for determining the length of time until the next one Calibration or for the decision to exchange the transducer or of another defective part or even for dynamic correction the measured values are used.
• - Thirdly, there is a separate "bookkeeping" on the career (or the Recalibrations) of the measuring module are unnecessary.
• - Fourth, there is a deletion of data on the non-volatile Memory module superfluous. This is particularly the case with only light-erasable ones Memory chips of greater use as these memory chips only are entirely solvable, so that other important information (e.g. Programs) get lost and have to be reloaded each time.

Of course, output measuring modules 3 '' can also be calibrated. For this purpose, the calibration computer 126 controls these and records the output values (not shown) with precision measuring devices which are also connected to the calibration computer 126. The calibration process is largely identical to that of the two measuring modules 3, 3 ' .

In conclusion, it should be noted that the specified module specifications are only Guidelines are. Of course, other compatible modules can also be used be used. It goes without saying that instead of the SMP bus concept also another (micro) processor bus concept with the associated one Block family can be used.

Claims (25)

1. Process measurement data acquisition and processing system for the acquisition and processing of several physical process variables, which are acquired via sensors (measuring modules) and preprocessed as data words via a bus system to one or more hierarchically tiered processing, control and coordination computers (central computer , Host computer), the measuring modules each recording one or more physical quantities at least one transducer that is structurally combined with this or detached from it, electrically conductive or connected to the measuring module via optical fibers for recording the physical quantity and converting it into an equivalent electrical one Signal, as well as circuits for processing and / or converting the electrical signal (s) and / or their amplification and / or for potential separation and / or for multiplexing and / or for analog / digital conversion of signals as well as a microcomputer which includes converted or digitally converted S. ignale takes over and conversion properties of the measuring modules such. B. adjusts non-linearities, gain and zero point errors of the transducers due to correction data stored in a non-volatile memory and provides measured values as data words for query by the central computer, characterized in that the bus system (mb.i, mb) is an extended processor bus of the central computer (4 . i , 4, 4 ' ) to which the measuring modules ( 3. ÿ , 3, 3', 3 '' ) can be switched or plugged. 2. Process measurement data acquisition and processing system for the acquisition and processing of several physical process variables, which are acquired via sensors (measuring modules) and preprocessed as data words via a bus system to one or more hierarchically graded processing, control and coordination computers (central computer , Host computer), the measuring modules each recording one or more physical quantities at least one transducer that is structurally combined with this or detached from it, electrically conductive or connected to the measuring module via optical fibers for recording the physical quantity and converting it into an equivalent electrical one Signal, as well as circuits for processing and / or converting the electrical signal (s) and / or their amplification and / or for potential separation and / or for multiplexing and / or for analog / digital conversion of signals as well as a microcomputer which includes converted or digitally converted S. ignale takes over and conversion properties of the measuring modules such. B. adjusts non-linearities, gain and zero point errors of the transducer due to correction data stored in a non-volatile memory and provides measured values as data words for query by the central computer, in particular according to claim 1, characterized in that the measuring modules ( 3. ÿ , 3, 3 ', 3'' ) is thawed with the central computer (4. i , 4, 4' ) connecting bus system (mb.i, mb) on the basis of a standardized, parallel microprocessor bus (SMP bus). 3. process measurement data acquisition and processing system according to claims 1 and 2, characterized in that the microcomputers ( 30, 36 ) of the measuring modules ( 3. ÿ , 3, 3 ', 3'' ) the recorded and corrected measured values in data words in a Convert normalized floating point format and buffer for retrieval by the central computer ( 4. i , 4, 4 ' ) in a memory ( 39 ) with random access. 4. Process measurement data acquisition and processing system according to at least one of the preceding claims, characterized in that the measuring modules ( 3. ÿ , 3, 3 ', 3'' ) from the central computer (4. i , 4, 4' ) to retrieve the data words can be addressed via the microprocessor bus (mb.i, mb) using an address word corresponding to a measuring module-specific address. 5. Process measurement data acquisition and processing system according to claim 4, characterized in that the address in the measuring module is set at least adjustable by coding switches and by a PAL module (Programmable Array Logic) ( 32, 34 ) and / or a wiring field ( 33, 45 ) is decoded. 6. Process measurement data acquisition and processing system according to claim 5, characterized in that at least part of the measurement module-specific address accordingly of the type of measurement module ( 3. ÿ , 3, 3 ', 3'' ) and / or the number of similar measurement modules used -Types within the process measurement data acquisition and processing system and / or the type of the measuring module ( 3. ÿ , 3, 3 ', 3'' ) and / or according to the type of physical quantity recorded (mp.ÿ) and / or according to the Measuring range is determined. 7. Process measurement data acquisition and processing system according to claim 6, characterized in that a rate at which the measuring modules detect the physical quantities (mp.ÿ) is set within the measuring modules ( 3. ÿ , 3, 3 ', 3'' ) , but can be configured from the central computer (4. i , 4 ) via the bus system (mb.i, mb). 8. process measurement data acquisition and processing system according to claim 7, characterized in that the system by means of a slide-in system ( 7 ) (racks) is rea lized that a power supply ( 13, 14 ) and the bus system ( 10-12 ) comprises on the the central computer (4. i , 4, 4 ' ) and the measuring modules ( 3. ÿ , 3, 3', 3 '' ) realized as inserts in only by a maximum length of the microprocessor bus and the installation space of the measuring modules ( 3. ÿ , 3, 3 ', 3'' ) limited number and any configuration according to the measurement task can be attached. 9. Process measurement data acquisition and processing system according to at least one of the preceding claims, characterized in that the microcomputer ( 36 ) of the measuring modules ( 3 ' ) also takes over tasks of data preselection and / or data pre-compression and / or data processing and / or data intermediate storage . 10. Process data acquisition and processing system according to claim 9, characterized in that the measuring module ( 3 ' ) additionally comprises a dual-port RAM ( 41 ) inserted between the microcomputer ( 36 ) and bus system (mb) , into which data, addresses or Instructions can be read in, read out or temporarily stored both from the microcomputer ( 36 ) and from the central computer (4. i , 4, 4 '). 11. Process measurement data acquisition and processing system according to claims 9 or 10, characterized in that the tasks of the microcomputer by a processing and conversion of the measurement data serving processing processor ( 36 ) and a coupled with this, the control of components ( 21 to 28 ) the measuring modules ( 3 ' ) serving control processor (35 ) are made. 12. Process measurement data acquisition and processing system according to claim 9, 10 or 11, characterized in that the measuring modules ( 3 ' ) have an additional serial interface ( 47 ) via which the measuring modules ( 3' ) can be configured at any time, ie can be loaded with measuring programs and / or can be calibrated and / or via which a data connection (sb) to submodules can be created. 13. Process measurement data acquisition and processing system according to at least one of the preceding claims, characterized in that the system ( 1 ) can also be equipped with addressable output measuring modules ( 3 '' ), with which process-controlling variables by means of a microcomputer ( 48 ) controlled electrophysical transducers are applied. 14. Process measurement data acquisition and processing system according to claim 9, characterized in that the control of the output measuring modules ( 3 '' ) by the central computer (4. i , 4, 4 ' ) by outputting an output module address and a control word in normalized floating point format takes place, which is implemented by the microcomputer ( 48 ) of the output measuring module ( 3 '' ) in a control value for the electrophysical converter or for driver circuits ( 56, 57 ) of the electrophysical converter in such a way that the process-controlling variable has a value proportional to the control word assumes, with static and / or dynamic conversion properties of the output measuring modules ( 3 '' ), such as. B. nonlinearities, gain and zero point errors, etc. of the output measuring modules ( 3 '' ) are adjusted due to correction data stored in a non-volatile memory abge. 15. Process measurement data acquisition and processing system according to claim 13 or 14, characterized in that the output measuring module ( 3 '' ) additionally has a sensor for detecting the process-controlling variables and converting them into an equivalent electrical signal, as well as circuits for processing and / or conversion of the electrical signal and / or its amplification and / or for potential separation ( 66, 67 ) and / or for analog / digital conversion and a control loop implemented on the microcomputer (48 ) with which the control value of the electrophysical converter is controlled that the process-controlling variable optimally follows its setpoint. 16. Process measurement data acquisition and processing system according to claim 15, characterized in that the system can be used as a mobile measurement data system, this being a slide-in system ( 7 ) with the standardized, parallel microprocessor bus ( 10-12 ), a power supply ( 14 ) and A drawer space for any measuring modules ( 3. ÿ , 3, 3 ' ) and output measuring modules ( 3'' ), a central computer and a mass storage device for measured values and measuring programs and is equipped with a display and a hand-held input device, where a mass storage device includes external interface for loading measurement programs and reading out measurement data and can be used to intervene at least partially in a sequence of a measurement program with the hand-held device. 17. Process measurement data acquisition and processing system for the acquisition and processing of several physical quantities, which are acquired via sensors (measuring modules) and preprocessed as data words via a bus system to one or more hierarchically tiered processing, control and coordination computers (central computer, host computer) are transmitted, the measuring modules each detecting one or more physical quantities at least one transducer that is structurally combined with this or detached from it, electrically conductive or connected to the measuring module via optical fibers for detecting the physical quantity and converting it into an equivalent electrical signal, as well as Circuits for processing and / or converting the electrical signal (s) and / or their amplification and / or for potential separation and / or for multiplexing and / or for analog / digital conversion of signals as well as a microcomputer which includes converted or digitally converted signals u takes over and adjusts non-linearities, gain and zero point errors of the transducers on the basis of correction data stored in a non-volatile memory and provides measured values as data words for query by the central computer, in particular according to at least one of the preceding claims, characterized in that the one interface for a standardized microprocessor bus ( mb , SMP bus) and / or a serial interface having measuring module ( 3, 3 ' ) correction data for comparing static and / or dynamic conversion properties, such as. B. comprises a non-volatile memory, in the non-linearities, gain and zero point errors, etc. are always written into new memory locations during a calibration and only one stored in a storage location of the non-volatile memory, at the beginning of a data set with the current calibration data indicative address is updated. 18. Process measurement data acquisition and processing system according to claim 17, there characterized in that the non-volatile memory module is an electrical erasable and programmable memory chip (EPROM). 19. Process measurement data acquisition and processing system according to claim 18, characterized in that the non-volatile memory module is a battery-buffered memory module ( 39 ) with random access (RAM). 20. Process measurement data acquisition and processing system according to at least one of claims 17 to 19, characterized in that the system further comprises a calibration system (125 ) which has a calibration computer ( 126 ), a system controllable by this for providing variable calibration variables or calibration standards ( Calibration source device 130 , controllable air conditioning systems 131 ) and a calibration slide-in system (132 ) on which measuring modules ( 3, 3 ', 3'' ) to be calibrated via the standardized microcomputer bus (mb , SMP bus) and / or the serial interface ( 47 , serial bus system sb) can be connected to the calibration computer (126 ) for calibration, with an initial calibration

• - In a first phase of the calibration, the measuring modules ( 3, 3 ' ) and with calibration normal or calibration variables (pkg. 1 to pkg.y) of variable values within the measuring range of the measuring module ( 3, 3' ) are applied, the measuring module ( 3, 3 ′ ) due to non-existent correction data, uncorrected, unconverted data is switched to the bus system (mb) , which is compared with target data by the calibration computer ( 126),
• - In a second calibration phase, the calibration computer ( 126 ) calculates correction data and provides or writes them to the corresponding memory cells of the measuring module ( 3, 3 '') for writing,
• - In a third phase of the calibration, the measuring modules ( 3, 3 ' ) and again with calibration standards or calibration variables (pkg. 1 to pkg.v) of variable values within the measuring range of the measuring module ( 3, 3' ) are applied, the measuring module ( 3, 3 ' ) switches the recorded data, corrected based on the new correction data and converted into the standardized data format, to the bus system (mb) , which are compared again with the target data by the calibration computer ( 126 ), so that if a predetermined tolerance band is exceeded, the calibration can be repeated if necessary.

21. Process measurement data acquisition and processing system according to claim 20, characterized in that during a recalibration

• - In a first phase the measuring modules ( 3, 3 ' ) are acted upon with calibration standards or calibration variables (pgk. 1 to pkg.y) of variable values within the measuring range of the measuring module ( 3, 3' ), the measuring module ( 3, 3 ') ) the recorded data, corrected on the basis of the old correction data and converted into the standardized data format, connects to the bus system (mb) , which are compared by the calibration computer ( 126 ) with the target data, so that the calibration is aborted when the specified tolerance band is adhered to and when a predetermined tolerance band, the calibration computer ( 126 ) updates the address stored in the memory space of the non-volatile memory ( 39 ), pointing to a new (and not yet available) data record with new calibration data, and the measuring module ( 3, 3 ' ) with calibration standards or calibration variables variable values within the measuring range of the measuring module ( 3, 3 ' ) applied, the measuring module ( 3, 3' ) due to the non-existent nths the data record, not corrected and unconverted data is applied to the bus system (mb) , which is compared by the calibration computer ( 126 ) with target data,
• - In a second phase of the recalibration, the calibration computer ( 126 ) calculates correction data and provides or writes them to the corresponding, newly addressed memory cells of the measuring module ( 3, 3 '),
• - In a third phase of recalibration, the measuring modules ( 3, 3 ' ) are again acted upon by the calibration computer (126 ) with calibration standards or calibration variables (pkg. 1 to pkg.y) variable values within the measuring range of the measuring module ( 3, 3' ) , the measuring module ( 3, 3 ' ) activating the recorded data, corrected on the basis of the new correction data and converted into the standardized data format, onto the bus system (mb) , which are compared again with the target data by the calibration computer ( 126) so that when exceeded within a predetermined tolerance band, the recalibration can be repeated if necessary.

22. Process measurement data acquisition and processing system according to claim 21, characterized in that the calibration slide-in system (132 ) for measuring modules ( 3 ) with EPROM or EEPROM also provides erasing and programming voltages which are supplied via unused lines (139 ) of the microprocessor bus (mb) can be fed into the EPROM or EEPROM via this. 23. Process measurement data acquisition and processing system according to claim 21, characterized in that the calibration computer (126 ) for measuring modules ( 3 ) with an additional serial interface ( 47 ) provides the calibration data via this, so that they are from the measuring module ( 3 ' ) in the corresponding memory cells of the battery-backed memory ( 39 ) can be read. 24. Process measurement data acquisition and processing system according to claim 22 or 23, characterized in that the calibration computer (126 ) read out old calibration values from the memory ( 39 ) of the measuring modules ( 3, 3 ' ) and, on the basis of this, determine the aging behavior of the transducer by trend analysis and may indicate that the transducer needs to be replaced. 25. Process measurement data acquisition and processing system according to claim 22, characterized in that a plotter ( 133 ) is connected to the calibration computer (126 ), on the measured values during calibration and tolerance bands and the aging behavior of the components (21 to 28 ) of the measuring modules ( 3, 3 ' ) can be represented graphically.