CA1291246C - Modular automatic controller, preferably programmable, in particular for mining plant - Google Patents
Modular automatic controller, preferably programmable, in particular for mining plantInfo
- Publication number
- CA1291246C CA1291246C CA000514710A CA514710A CA1291246C CA 1291246 C CA1291246 C CA 1291246C CA 000514710 A CA000514710 A CA 000514710A CA 514710 A CA514710 A CA 514710A CA 1291246 C CA1291246 C CA 1291246C
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- Prior art keywords
- input
- board
- bus
- rack
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- Prior art date
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Classifications
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
- G05B19/05—Programmable logic controllers, e.g. simulating logic interconnections of signals according to ladder diagrams or function charts
- G05B19/058—Safety, monitoring
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
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- G05B2219/1127—Selector for I-O, multiplex for I-O
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- G05B2219/1162—Forcing I-O
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- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
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- G05B2219/1193—I-O ram as buffer for signals and self test for I-O bus
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- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
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- G05B2219/13033—Code wheel to enter data, push button to accept
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- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
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- G05B2219/00—Program-control systems
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- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
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Abstract
TITLE OF THE INVENTION
" Modular automatic controller, preferably programmable, in particular for mining plant "
TEXT OF THE ABSTRACT
An automatic controller adapted to control actuators according to the state of sensors, of the kind comprising a central unit and input/out boards, comprises a first connecting bus associated with the central unit, a second connecting bus connecting to this first bus, through a bus interface module, at least one control board and at least a third connecting bus BES
connecting a group of input/output boards to this control board.
It may among others be used for automating mining plant in particular.
" Modular automatic controller, preferably programmable, in particular for mining plant "
TEXT OF THE ABSTRACT
An automatic controller adapted to control actuators according to the state of sensors, of the kind comprising a central unit and input/out boards, comprises a first connecting bus associated with the central unit, a second connecting bus connecting to this first bus, through a bus interface module, at least one control board and at least a third connecting bus BES
connecting a group of input/output boards to this control board.
It may among others be used for automating mining plant in particular.
Description
The present invention concerns an automatic controller for controlling actuators from sensors, preferably programmable and in particular for mining plant.
S As a general rule automation has a number of advantages, as in the mining sector, for example. It permits, among other things:
- increased user safety (monitoring of the safety of personnel embarked on a conveyor), - execution of tasks otherwise impossible or difficult in that they necessitate mobilisation of large numbers of workers (transportation and sorting of coal from dead rock or sorting different grades of coal), - increased performance of installations and machinery.
Control systems and specifically automatic control]ers for machinery and installations have been used in mining for many years but the growth in their use has been slow. There are various reasons for this:
- the systems are generally complex and necessitate highly qualified personnel requiring training in numerous areas, - breakdowns are not always easy to detect.
With the appearance of automatic controllers that can be programmed by their users, signi~icant advances have become possible in the field of automatic control.
Unlike other computer-type systems, the programmable automatic controller has the important advantage of not requiring costly and complicated programs that take a long time to write. Personnel can be trained to operat~ an automatic controller extremely quickly, in just a few weeks.
~lso, the requirements of users frequently change quickly a`nd an automatic controller has ~he advankag~ o~ not r~quiring any human in~rven~ion at the wiring level, for example to add or remove sensors in the automatic control system or to extend the system to another machine or installation. ~sing conventional equipment, such operations could entail bringing the equipment to the surface for modification in the workshop, with all the transportation, administration and execution times that this would involve and possible ris~ of damage.
Thought might be given in particular to automating the conveyor installation, the pumping system control unit, the chair lift monitoring system, etc.
Various applications using commercial automatic controllers designed normally to operate in an industrial environment have shown the need for a modular automatic controller, preferably programmable and using standard units, adapted to the peculiar conditions of working at the bottom of mines liable to fire-damp, able to replace the numerous types of relay system as generally used.
These considerations lead to a definition of the following constraints associated with operating conditions in a mining environment:
- equipment security: the programmable automatic controller, apart from the power supply and output circuits, must be intrinsically safe (level Ib of european standards);
- the sensor connectin~ lines and the state of the sensors must be monitored at all times;
- transmission of information must be provided for with a view to centralised control of a number of machines;
- easy and ~ast troubleshooting;
- high reliability ~iven the operating conditions;
- reliable operation (automatic controller self-monitoring); ~`
3~ - elec~rical sa~c~y ~huilt-in means ~or checking correct 1 functioning)-To this end the invention proposes an automatic controller adapted to control actuators according to the state of sensors, of the kind comprising a central unit and input/output boards connected to the sensors and to the actuators, characterised in that it comprises a first bus connecting the constituent units of the central unit, a second bus connecting at least one control board to the first bus through an interface module and at least a third bus connecting a group of input/output board to each control board.
This arrangement confers on an auto~atic controller in accordance with the invention a highly flexible, modular character, in terms of the number of control board used and therefore of input/output boards that can be controlled.
In another of its aspects this invention provides for a centralised controller lncluding a single processing unit for controlling actuators depending on the state of sensors, comprising a set of adjacent board racks, a central unit housed in said set of racks including a plurality of constituent units, one of which is said single processing unit, a first bus within said central unit connecting said constituent units to each other, a modular user part also housed in said set of racks and comprising a plurality of input/output boards respectively connected to said actuators and to said sensors, the number of said input/output boards in said plurality being selected depending on the number of said actuators and sensors, said plurality of input/output boards being distributed in at least two board groups, each of said group being located in one rack in said set of racks which is specific to said group, a rack board and rack bus for each said groups in said specific rack, said rack bus connecting each said input/output board in said group to ~i .
3a 2~
1 said rack board, a second bus connecting all the said rack boards to each other, and a bus interface b~ard connecting said first bus to said second bus.
In one preferred embodiment of the invention the S automatic controller is connected to various sensors or actuators by a unidirectional conductor component (diode) circuit connected in reverse parallel with an alternating current supply, current being enabled to pass through one or the other of these unidirectional components according to whether a mobile element of a particular sensor or a particular actuator closes one or the other of the parallel branches in which these components are included: in this way it is possible to determine the position of this mobile element, a break or a short-circuit in the connecting lines to this sensor or to this actuator.
. According to another preferred embodiment of the invention, certain at least of the input/output boards are provided on their front panel with display elements associated with certain at least of the inputs/outputs controlled by the boards, these elements being advantageously adapted to rea~t differently to the four types of information that have just been stated.
Various types of input board are proposed by the invention, in particular boards for entry of parameters and multiplexed input boards associated with remote input modules.
According to another preferred embodi~ent of the invention, the automatic controller is provided with a dialogue module to enable the transfer into the central unit of user programs developped remotely on a console connected to said module by a dialogue bus.
The objects, characteristics and ad~antages of the invention will emerge from the following description given by way of non-limiting example and with reference to the appended drawings, in which:
- figure 1 is a schematic view of the configuration of an automatic controller in accordance with the invention comprising a number of racks containing electronic circuit boards;
- figure 2 is a block diagram of the central part of the automatic controller from figure 1;
- figure 3 is a block diagram of a rack control module;
- figure 4 is a block diagram o~ a parameter adjustment module;
- figure 5 is a block diagram o~ a multiplexed digital input module;
~ figure 6 is an electrical schematic of the connection from the ~ultiplexed digital input module in figure S to eight sensors through the intermediary of a remote multiplexed digital input module;
- figure 7 is a block diagram of a remote multiplexed digital input module of this kind;
- figure 8 is a block diagram of a high-speed digital input module;
- ~igur~ 9 is a block diagram o~ a digital output mQdule;
- figure 10 is an electrical diagram showing the connection of a sensor to the automatic controller.
The automatic controller in accordance with the invention shown in figure 1 is made up of elementary modules the number of which depends on the application in question. This automatic controller has a large configuration with 38 x 8 inputs/outputs; it is presented in a ~orm adapted to controlling mining plant.
The automatic controller comprises power supplies and SI/NSI (intrinsically safe) t~pe interfaces connected to outputs in explosion-proof housings 20 and 21 rigidly fastened to a set of racks 22 through 28 in IP 55 grade commercial sheet metal (the requirement for intrinsic safety requires at least IP 54 grade). The housings are fitted with explosion-proo~ lead-throughs whereby the intrinsically safe power supply outputs can be taken directly into the set of racks in which are accommodated electronic circuits implemented on printed circuit boards and terminal blocks for the connections to sensors and actuators. The various sheet metal racks are also rigidly fastened together and there is direct mechanical communication between them.
These sheet metal racks may be dlvided into two groups. Racks 22 through 24 are each adapted to contain 16 boards (or the equivalent) to the appropriate standard format, whereas the racks 25 through 2~ contain interconnect boards, ~or example four or ~ive boards each carrying 16 staged terminal blocks. These interconnect racks make the connection with a dialogue bus BD, a bus BC linked directly to sensors C and a bus BMD linked to remote multiplexed input modules EDM.
The racks 22 through 24 comprise a central unit UC which is in practice included in all configurations and a modular part reserved ~or the user. In the example shown the eentral unit occupie~ the e~uivalent o~ seven boards in the rack 22 with the user part occupying the remainder of this rack 22 and all of the racks 23 and 24. By virtue of one advantageous characteristic of the invention, each of these racks contains a rack control board leaving 38 slots for boards each with eight input/outputs or their equivalent in terms of volume.
In a simplified version the auto~atic controller might be reduced to racks 20, 22 and 25 only.
The racks and the explosion-proof housings are in practice used primarily for the power supply and the actuators only. The racks are pre~erably equipped with:
- an explosion-proof input for the connection to the electrical mains supply in the mine (1 100 V); an isolator switchbox may be fitted to this input, - inspection ports on the door (~or monitoring correct functioning of the power supplies), - explosion-proo~ lead-throughs (18 each with three conductors) feeding directly into the sheet metal rack~
containing the intrinsically safe electronic equipment.
In the example under consideration the housing 20 contains - a 1 100 V/220 V trans~ormer providing the mains power supply to the various power supply modules, - various power supply modules:
. 5 V-5 A DC power supply converter ~AL5CC) providing a power supply to all electronic circuit boards in the automatic controller;
. 12 V-1.5 A DC converter (AL12CC) providing a power supply to the actuator inter~aces (electromechanical or solid-state relays), . ~ 12 V-~20 ~A power supply (AL12CC~ ~or the analogue input and output boards, . multiple-outpllt 16 V alternating curr~nt power supply (A~16CA) (10~ to ~upply current to the input circuit5 L2~i with line monitoring (12 V or 24 V option).
It is generally necessary to provide several 16 V power supplies since because the supplies must be intrinsically safe they can supply only 32 input circuits. The requirement ~or intrinsically safe working also means that a 16 V voltage is preferable to the voltages of 12 V (as used in Germany) or 24 V (as more usually used in France).
The outputs of the various power supplies are intrinsically safe. As the requirement ~or intrinsic safety does not permit any mi~ing of outputs, it is mandatory to provide galvanic isolation between the various supplies.
The sheet metal racks 22 through 28 are in three parts, hinged laterally:
- a basic element with openings at the top and bottom, possibly closed off by blanking plates, - a frame pivoting 90 to the left relative to the basic element and adapted to receive a card-frame to european standards, - a glazed door pivoting 90 to the left relative to the frame.
The glazed door makes it possible to observe the various indicators on the ~ront panels of the electronic circuit boards (input and output states).
These racks may be joined together to suit the size o~ the application ~number o~ inputs/outputs). The openings in the top and bottom provide ~or inter-rack wiring.
Racks 25 through 28 accommodating the terminal blocks Eor the connections to the sensors and the actuators comprise only the basic element and a hinged solid door ~the pivoting ~rame is not used~.
The connections between the central unit UC and ~he u~er part arQ shown in ~icJure 2, in whiGh are seen 2~i three separate buses: a microprocessor bus ~M, an inter-rack bus BIC and input/output buses BES.
The central unit part, shown on the le~t, comprises a processing unit part, a display element and an interface module between the buses BM and BIC.
The processing unit part comprises a micro-processor unit MPU, a random access memory (RAM) board (this memory can be read and written), a system EPROM
board and a user EPROM board, a board for dialogue with a development system and an optional board for dialogue with another automatic controller.
The boards constituting the processing unit ~ay be com~ercially available boards, ~or example, the only constraints applying to the choice of these boards being as follows: single 5 V supply, no self-induction coil and low value capacitors (< l00 ~F).
In practice commercially available boards using recent technology will meet these conditions.
To give an example, the automatic controller under consideration is e~uipped with industrial grade (-40C to +85C) boards to the Eurocard format (100 x 160 mm~ and the National Semiconductor CIMsUS
standard, using the NSC 800 microprocessor (C~IOS
technology):
- microprocessor (MPU) board - CIM 804, - system RAM board - CIM 108, system EPROM board - CIM 10Q, - user EPROM board - CIM 100, - development system dialogue board (RS232C serial link and current loop) - CIM 201, - (optional) inter-controller dialogue board (identical connection to previous connection) - CIM 201.
In principle the 5ystem EPROM contains the various pro~rams needed for the automatic controller to unction: link with a development system, automatic controller language interpreter, test program, etc.
The MPU and RA~ boards are in practice combined in an MPU + RAM cartridge, the EPROM boards in an EPRO~
cartridge and the dialogue boards in a DIA module.
In the example under consideration programs can be written and debugged on the surface using the MERLIN
GERIN CDE 1000 programming console with which the automa~ic controller is compatible at connection and dialogue (BD) level. The programming languages used are the same as those used by MERLIN GERIN for its PS range of automatic controllers, namely: GRAFCET, SCHEMA RELAIS
and ASSEMBLEUR PB. The source program (GRAFCET, SCHE~tA
RELAIS or ASSEMBLEUR) is entered ~rom the keyboard of the CDE 1000 console. Once all of the source program has been entered it is compiled to obtain a runnable program (understandable by the automatic controller) which is transferred into the EPROM in the "EPROM
CARTRIDGE" module through a cable connected to the console. The "EPROM CARTRIDGE" is then plugged into:
- the automatic controller at the surface for preliminary tests, - (in its final version) the automatic controller down the mine once the program has been fully tested on the surface.
If the program is not free of bugs the "EPROM
CARTRIDGE" can be erased in the known manner by exposing it to UV radiation.
The display unit (VISU in the diagrams) controls a block of two 7-segment displays which indicate in coded form mal~unctions o~ the system noted by the processing unit. They can also be used by the user program (for example to display the current stage or the reason or a halt - in coded Eorm) or by the system pr~ram ~o verify ~orr~ct execution of khe user program.
By vir~ue o~ ~ne adv~nt~geous ch~racteristic oE
the invention the VISU unit, connected directly to the microprocessor bus, continues to function even in the event of a breakdown on the user part.
The inter-bus interface module MIB provides isolation between the user part and the system part, an essential characteristics of the invention. Thus a breakdown affecting a rac~ controller or an input/output module will not disrupt operation of the microprocessor module. As the display unit (and any associated test unit) is (or are) connected directly to the microprocessor bus, without passing through the bus inter~ace module and without any connection to the user part, the system maintenance and fault indication functions are preserved whatever units are faulty.
The MIB module also handles management (possibly including temporary storage) of the various signals necessary to the user part (input/output bus) and address decoding for selecting rack controller modules.
A self-monitoring or "watchdog" function is advantageously provided. Its theory of operation is as follows: a monostable has to be reset every 200 ms at most or it de-energises a relay coil 50 shutting down the controlled process. The automat under consideration here is advantageously equipped with two "watchdogs":
- one driven by the system software (invalid execution of instructions from the microprocessor de-energises the corresponding relay);
- the other driven by the user program: in this case the user must include periodically in his program the instruction to reset the monostable. Thus any malfunctioning o~ the user program will de-energise both "watchdog" relays.
There is also a synchronisation and clock board (not shown) whose ~unction is to generate and distribute 3S all the clock signals n~cessary to the processing unit ll and the various modules. In particular, it produces a synchronisation and power supply combined signal fed to the remote multiplexed input modules. This is preferably an alternating current signal in which one cycle is periodically nulled (see figure 7).
As previously stated, the user part comprises an inter-rack bus BIC which terminates at a rack control board CCl, CC2 or CC3 (of type ID 15) in each of the racks 22, 23 and 24.
10Although the microprocessor bus BM is short so that signals can traverse it quickly, the inter-rack bus BIC featuras a reduced number of conductors and the signals that it carries are slowed down. There is also in each rack an input/output bus BES already mentioned - 15and, at the rack output, the BC or BND output buses (see figure 1) that are possibly connected through intrinsically safe interface modules ISI.
The various signals that can travel on the buses are divided between:
- data lines denoted DO through D7, - address lines denoted AO throu~h A3 corresponding to a selection of functions or denoted A4 through A7, - a read/write line denoted R/W, and - a data acknowledge line and a dedicated line o rank in each rack of rank n.
The schematics of the various modules are self-explanatory and will be described only in outline.
Interconnect is standardised. All slots in a rack 22, 23 or 24 are wired identically and can accommodate any type of input/output module.
All input/output modules have an identification code specific to their type. This code is read by the processing unit. When the user software is being written in the langua~e o~ the automatic controller, the u~or will have to ~in~ khe pQsitiQn o~ th~ inpuk and output modules in the racks and will therefore have to produce a configuration table. The processing unit compares the code as read at the various slots with that recorded in the table. If these are not identical for any slot (board missing, board failure or wrong type of board), the user program stops, the "watchdog" stops the process and a code is shown on the displays.
Inputs are acquired synchronously with the clock signals and the processing unit then exploits the redundancy of the acquired data to form a working memory image used by the user program. This memory image is refreshed as and when the user sees fit by means of an appropriate instruction in the automatic controller language.
Figure 3 is a block diagram of a rack control board CCl, CC2 or CC3. This board principally incorporates a bidirectional buffer memory MTB inserted in the data bus D0-D7, a second buffer memory MTF at which the function select lines A0-A3 terminate, a board self-test module MAC connected to lines B0-B7 and to lines A0-A3, and a module MSC for decoding the number of a given board to which are connected lines A4-A7 and a rack controller select line SCC. The outputs of this board comprise data lines D0-D7, function select address lines A0-A3 and lines N selecting boards in the corresponding rack (8 or 15 wires).
In each rack this board isolates and te~porarily stores signals intended for the 15 (or eight) slots that lt can address (functions similar to the bus interface module).
This board or module also has a self-monitoring role in relation to the input/output bus distributed to the 15 slots.
It is used to veri~y correct ~unctioning o~ the input/output ~us and the link connecting it to the bus interface module MIs.
Thus any fault on the input/output bus of a rack is signalled to the processing unit and does not affect the functioning of the other racks.
Each module CC1, CC2 or CC3 controls a subgroup of input/output boards. There are various types of input-output module: parameter adjustment modules PAR, multiplexed digital input modules ENM adapted to be connected to remote multiplexed digital input modules EDM, high-speed digital input modules ENR (direct connection) and digital output modules SN.
Figure 4 is a block diagram of an input/output PAR module occupying two slots in a rack (see figure 1) for in situ adjustment of parameters such as: time-delays, triggering thresholds, counter/downcounter set points, operating modes, etc.
A module of this kind comprises at least one thumbwheel RC associated with each parameter to be adjusted (in this instance eight pairs of thumbwheels permitting adjustment of eight parameters to values between 00 and 99). This module preferably further comprises a plurality of TTL inputs (in this instance 16 inputs denoted E0 throu~h E~) available on a terminal block in one of the racks 25 throu~h 28. The inputs are 2S designed to be connected to switches inside the auto~atic controller or to be shunted at the terminal block by means of straps. The inputs are essentially intended Eor maintenance and emergency process control.
The figure 4 PAR module principally comprises, in addition to the thumbwheels RC, a decoder DEC
connected to the select lines A0-A3 and an addressing line Erom a logic module MLl to which ~re routed read and rack number lines R and NR; the decoder DEC is also connoctod to the ~humbwheels, a buf~er memory MTRC
~5 connected to the ~humbwheels by a thumbwheel read bus BRC, and to the data bus D0-D7, and multiplexing unit MP
connected to the data bus D0-D7, to the TTL inputs denoted ~0 through EF to board type lines TC, to the lines A0-A3 and to an output line from a second logic module ML2. Each of the multiplexing units provides two signals selected rom two groups each of four signals.
By pressing a pushbutton BP and through the intermediary of a bistable BL the user can read the values set on the thumbwheels at any time he wishes; these values are recognised immediately and substituted for the values previously read. A PAR module of this kind is a special input module by means of which a user can enter data himself, the thumbwheels themselves indicating the status of the inputs that they constitute.
lS As will shortly emerge and in accordance with one advantageous embodiment of ~he invention, the other input/output modules are equipped with display devices -preferably indicator lamps - adapted to be controlled by the processing unit itself so as to display at this module the state of the inputs/outputs connected to this module as it is seen by the processing unit. There are preferably display devices adapted to display the state of each input/output, according to whether the associated actuator or sensor is in the one or the other of its basic conditions, or whether the connecting line to the actuator or the sensor is short-circuited or open-circuit (see below in relation to igure 10).
It is important to note that as these lamps are controlled directly by the processing unit and not through wiring it is certain that the state of the lamps corresponds to the state as "seen" by the processing unit; the state of each input (or output) is regularly (for example: every 1~0 ms) sampled, and the result of thi~ sampling is stored in a memory image that can be rcad a~ any ~ime.
.: . ~ , -.
~'9:~2~
Figure 5 is a block diagram of a multiplexed digital input board or module ENM. Each module of this type, adapted to manage eight remote inputs, is connected by a four-wire remote input bus BED
(comprising two telephone pairs, for example) to a remote module EDM (schematically represented in figure 7) providing for successive scanning of eight sensors C
using a circuit represented schematically in figure 6.
The connection with the remote block EDM and to the sensor C is o~ intrinsically safe level Ia and may be as long as 4 km, for example.
The ENM board principally comprises two shift registers RDl and RD2 followed by two multiplexers MPl and MP2 connected to line A0 and two latches Ll and L2 between which are connected in reverse parallel light-emitting diodes DEL constituting indicator lamps of different colours, green and red, for example.
The register RDl receives the signals from the associated remote module through a diode link LD and a clock signal CLK; one of its outputs is fed to the other register RD2, which also receives the signal CLK. Some inputs of the multiplexer MP2 may be ear~hed or connected to 5 V depending on the sattin~ of switches serving to indicate the type of microprocessor board.
The read line R, board number line N and write line W
are combined by logic devices whose outputs are fed either to the multiplexers or ~o the latches. The pairs of diodes DEL are used to display four different indi~ations according to whether positive or negative direct current or positive or negative rectified alternating current is applied to them.
The four wires oE the remote input buf~er BED
carry the data signals from the remote module EDM and a power supply ahd synchronisation signal ~already mQnti~ned hereinabove) from the automakic controller.
Each sensor C is connected to the associated EDM module by two wires.
As schematically represented in figure 7, the module EDM principally comprises a device RAS for rectifying the incoming power supply and synchronisation signals followed by an optocoupler link DPZ for detecting passages through zero the output of which is fed to a monostable MS and, like the clock signals CLK, to a counter CP16 designed to react through cycles of 16 pulses and to a decoder DEC10 adapted to react through cycles of 10 pulses. De-energisation of the monostable resets the counter and the decoder. For lines numbered 1 through 8 the decoder sucessively energises each of the sensors Cl through C8 the responses from which appear between output lines forming part of the bus BED.
A pair of modules ENM and EDM makes it possi~le to sample the inputs every 180 mns, but as already specified, the state of each input can be read at any time from the memory image.
For more frequent sampling, every 20 mns for example, it is possible to use a high~speed digital input module ENR as schematically represented in figure 8, with separate links to each of the associated sensors ~.
The link to the sensors is, as previously, of intrinsic safety level Ia and may be as long as 4 km, for example. The states of the various inputs are read simultaneously.
This module ENR principally comprises a buffer memory MTLS, a multiplexer MPLS and a display device ALS, all three equipped with select logic and connected to the data lines D0-D7, to the function select lines A0-A3 and to the board select lines N. Associated with th~ display ~ViG~ ALS is a set o~ front panel lamps ,~ L6 VFA, similar to the diodes DEL in figure 5, for example, while associated with the multiplexer MPLSD is a board type switch ITC. The buffer memory ITLS is connected to each of the sensors C by a galvanic isolation opto-coupler OC.
A digital output module SN is schematicallyrepresented in figure 9. It is used to control eight actuators ACT through galvanic isolation opto-electronic couplers COE (as the actuators are supplied with power from a different power supply, there is no mixing or interaction at this level). The actuators may be of the electromechanical or solid-state relay type; their control connections are intrinsically safe.
This module SN principally comprises a multi-plexer MLS equipped with select logic connected to thelines BO-B7, AO-A3 and N, to board type switches ITC and to couplers COE already mentioned, a select logic module LS connected to the lines N and AO-A3, a latch MRT
connected to the lines DO-D7 and to a select line Sl from the module LS and a display module MAF connected to the lines DO-D7 and to a select line S2 from the module LS, and controlling the front panel lamps VFA similar to those o~ figure 8.
It may be made possible to ~orce individually the excitation of the actuator, by means of a strap (not shown). Any such action is seen by the processing unit and made available to the user program in the working memory image: thus when writing his program the user can place the process in a fall~ack position cancelling the effects of any unacceptable forcing.
As for the input boards, each output state is displayed on the SN board at the automatic controller with one oE the two lamps lit continuously or intermi~t~n~ly. -.~ In ~he ca~e o~ ~oth sensor~ and ac~ua~or~, the lines connecting the~ to the remainder of the automatic controller are, in accordance with one advantageous characteristic of the invention, controlled by the circuit of figure 10.
A sensor C comprises an element EC movable between two fundamental positions 1 and 2 and two diodes Dl and D2 connected in reverse directions in two parallel branches linking the connecting llnes to an intrinsically safe alternating current supply U disposed in an associated input module. One of these connecting lines preferably comprises a photo-electronic detector formed by two light-emitting diodes connected in reverse parallel.
There appears across a resistor R provided in one of the lines in said associated module an alter-nating current voltage that i5 rectified positively in the even~ of contact at 1, rectified negatively in the event of contact at 2, of zero value in the event that one of the connecting lines is cut, or identical to the voltage delivered at U in the event of short-circuiting of the connecting lines. It is easy to associate with each of these forms of the voltage a specific mode of lighting the lamps on the front panel of e~ch input of output board (see figure 5 in particular).
In other words, in accordance with the invention the current in the resistor R is sampled on each half-cycle synchronously with the power supply so that the four aforementioned cases are obtained.
It will be noted that the invention makes it possible for the user program not to know the physical input~output addresses (internal real address of the registers in the input and output modules). The program addresses itsel~ to a workin~ memory ima~e situated in the RAM. ~rh~ sys tem 50Etware:
~ ac~uire~ all input skakqs synchronou~ly wi~h the clock signals and then, if it recognises a state corresponding to a fault (line cut or short-circuited), waits for the next acquisition cycle before validating the information (this makes it possible to avoid a change of sensor state being interpreted as a fault), - reads the outputs to test for any forcing, - processes all this information and controls the lamps appropriately.
The results of this processing are transferred into the working memory image by the system software only when it reads the refresh instruction RAFR in the user program.
It goes without saying that the foregoing description has been offered by way of non-limiting illustrative example only and that numerous variations may be proposed by those skilled in the art without departing from the scope of the invention, in particular regarding the number of inputs/outputs controlled by each board or the number of boards placed under the control of each rack control board ~dependent on the technology employed), the structure of the connecting buses and the detailed structure oE the various boards.
An automatic controller in accordance with the invention is in practice adapted to utilise a wide variety of input/output boards.
S As a general rule automation has a number of advantages, as in the mining sector, for example. It permits, among other things:
- increased user safety (monitoring of the safety of personnel embarked on a conveyor), - execution of tasks otherwise impossible or difficult in that they necessitate mobilisation of large numbers of workers (transportation and sorting of coal from dead rock or sorting different grades of coal), - increased performance of installations and machinery.
Control systems and specifically automatic control]ers for machinery and installations have been used in mining for many years but the growth in their use has been slow. There are various reasons for this:
- the systems are generally complex and necessitate highly qualified personnel requiring training in numerous areas, - breakdowns are not always easy to detect.
With the appearance of automatic controllers that can be programmed by their users, signi~icant advances have become possible in the field of automatic control.
Unlike other computer-type systems, the programmable automatic controller has the important advantage of not requiring costly and complicated programs that take a long time to write. Personnel can be trained to operat~ an automatic controller extremely quickly, in just a few weeks.
~lso, the requirements of users frequently change quickly a`nd an automatic controller has ~he advankag~ o~ not r~quiring any human in~rven~ion at the wiring level, for example to add or remove sensors in the automatic control system or to extend the system to another machine or installation. ~sing conventional equipment, such operations could entail bringing the equipment to the surface for modification in the workshop, with all the transportation, administration and execution times that this would involve and possible ris~ of damage.
Thought might be given in particular to automating the conveyor installation, the pumping system control unit, the chair lift monitoring system, etc.
Various applications using commercial automatic controllers designed normally to operate in an industrial environment have shown the need for a modular automatic controller, preferably programmable and using standard units, adapted to the peculiar conditions of working at the bottom of mines liable to fire-damp, able to replace the numerous types of relay system as generally used.
These considerations lead to a definition of the following constraints associated with operating conditions in a mining environment:
- equipment security: the programmable automatic controller, apart from the power supply and output circuits, must be intrinsically safe (level Ib of european standards);
- the sensor connectin~ lines and the state of the sensors must be monitored at all times;
- transmission of information must be provided for with a view to centralised control of a number of machines;
- easy and ~ast troubleshooting;
- high reliability ~iven the operating conditions;
- reliable operation (automatic controller self-monitoring); ~`
3~ - elec~rical sa~c~y ~huilt-in means ~or checking correct 1 functioning)-To this end the invention proposes an automatic controller adapted to control actuators according to the state of sensors, of the kind comprising a central unit and input/output boards connected to the sensors and to the actuators, characterised in that it comprises a first bus connecting the constituent units of the central unit, a second bus connecting at least one control board to the first bus through an interface module and at least a third bus connecting a group of input/output board to each control board.
This arrangement confers on an auto~atic controller in accordance with the invention a highly flexible, modular character, in terms of the number of control board used and therefore of input/output boards that can be controlled.
In another of its aspects this invention provides for a centralised controller lncluding a single processing unit for controlling actuators depending on the state of sensors, comprising a set of adjacent board racks, a central unit housed in said set of racks including a plurality of constituent units, one of which is said single processing unit, a first bus within said central unit connecting said constituent units to each other, a modular user part also housed in said set of racks and comprising a plurality of input/output boards respectively connected to said actuators and to said sensors, the number of said input/output boards in said plurality being selected depending on the number of said actuators and sensors, said plurality of input/output boards being distributed in at least two board groups, each of said group being located in one rack in said set of racks which is specific to said group, a rack board and rack bus for each said groups in said specific rack, said rack bus connecting each said input/output board in said group to ~i .
3a 2~
1 said rack board, a second bus connecting all the said rack boards to each other, and a bus interface b~ard connecting said first bus to said second bus.
In one preferred embodiment of the invention the S automatic controller is connected to various sensors or actuators by a unidirectional conductor component (diode) circuit connected in reverse parallel with an alternating current supply, current being enabled to pass through one or the other of these unidirectional components according to whether a mobile element of a particular sensor or a particular actuator closes one or the other of the parallel branches in which these components are included: in this way it is possible to determine the position of this mobile element, a break or a short-circuit in the connecting lines to this sensor or to this actuator.
. According to another preferred embodiment of the invention, certain at least of the input/output boards are provided on their front panel with display elements associated with certain at least of the inputs/outputs controlled by the boards, these elements being advantageously adapted to rea~t differently to the four types of information that have just been stated.
Various types of input board are proposed by the invention, in particular boards for entry of parameters and multiplexed input boards associated with remote input modules.
According to another preferred embodi~ent of the invention, the automatic controller is provided with a dialogue module to enable the transfer into the central unit of user programs developped remotely on a console connected to said module by a dialogue bus.
The objects, characteristics and ad~antages of the invention will emerge from the following description given by way of non-limiting example and with reference to the appended drawings, in which:
- figure 1 is a schematic view of the configuration of an automatic controller in accordance with the invention comprising a number of racks containing electronic circuit boards;
- figure 2 is a block diagram of the central part of the automatic controller from figure 1;
- figure 3 is a block diagram of a rack control module;
- figure 4 is a block diagram o~ a parameter adjustment module;
- figure 5 is a block diagram o~ a multiplexed digital input module;
~ figure 6 is an electrical schematic of the connection from the ~ultiplexed digital input module in figure S to eight sensors through the intermediary of a remote multiplexed digital input module;
- figure 7 is a block diagram of a remote multiplexed digital input module of this kind;
- figure 8 is a block diagram of a high-speed digital input module;
- ~igur~ 9 is a block diagram o~ a digital output mQdule;
- figure 10 is an electrical diagram showing the connection of a sensor to the automatic controller.
The automatic controller in accordance with the invention shown in figure 1 is made up of elementary modules the number of which depends on the application in question. This automatic controller has a large configuration with 38 x 8 inputs/outputs; it is presented in a ~orm adapted to controlling mining plant.
The automatic controller comprises power supplies and SI/NSI (intrinsically safe) t~pe interfaces connected to outputs in explosion-proof housings 20 and 21 rigidly fastened to a set of racks 22 through 28 in IP 55 grade commercial sheet metal (the requirement for intrinsic safety requires at least IP 54 grade). The housings are fitted with explosion-proo~ lead-throughs whereby the intrinsically safe power supply outputs can be taken directly into the set of racks in which are accommodated electronic circuits implemented on printed circuit boards and terminal blocks for the connections to sensors and actuators. The various sheet metal racks are also rigidly fastened together and there is direct mechanical communication between them.
These sheet metal racks may be dlvided into two groups. Racks 22 through 24 are each adapted to contain 16 boards (or the equivalent) to the appropriate standard format, whereas the racks 25 through 2~ contain interconnect boards, ~or example four or ~ive boards each carrying 16 staged terminal blocks. These interconnect racks make the connection with a dialogue bus BD, a bus BC linked directly to sensors C and a bus BMD linked to remote multiplexed input modules EDM.
The racks 22 through 24 comprise a central unit UC which is in practice included in all configurations and a modular part reserved ~or the user. In the example shown the eentral unit occupie~ the e~uivalent o~ seven boards in the rack 22 with the user part occupying the remainder of this rack 22 and all of the racks 23 and 24. By virtue of one advantageous characteristic of the invention, each of these racks contains a rack control board leaving 38 slots for boards each with eight input/outputs or their equivalent in terms of volume.
In a simplified version the auto~atic controller might be reduced to racks 20, 22 and 25 only.
The racks and the explosion-proof housings are in practice used primarily for the power supply and the actuators only. The racks are pre~erably equipped with:
- an explosion-proof input for the connection to the electrical mains supply in the mine (1 100 V); an isolator switchbox may be fitted to this input, - inspection ports on the door (~or monitoring correct functioning of the power supplies), - explosion-proo~ lead-throughs (18 each with three conductors) feeding directly into the sheet metal rack~
containing the intrinsically safe electronic equipment.
In the example under consideration the housing 20 contains - a 1 100 V/220 V trans~ormer providing the mains power supply to the various power supply modules, - various power supply modules:
. 5 V-5 A DC power supply converter ~AL5CC) providing a power supply to all electronic circuit boards in the automatic controller;
. 12 V-1.5 A DC converter (AL12CC) providing a power supply to the actuator inter~aces (electromechanical or solid-state relays), . ~ 12 V-~20 ~A power supply (AL12CC~ ~or the analogue input and output boards, . multiple-outpllt 16 V alternating curr~nt power supply (A~16CA) (10~ to ~upply current to the input circuit5 L2~i with line monitoring (12 V or 24 V option).
It is generally necessary to provide several 16 V power supplies since because the supplies must be intrinsically safe they can supply only 32 input circuits. The requirement ~or intrinsically safe working also means that a 16 V voltage is preferable to the voltages of 12 V (as used in Germany) or 24 V (as more usually used in France).
The outputs of the various power supplies are intrinsically safe. As the requirement ~or intrinsic safety does not permit any mi~ing of outputs, it is mandatory to provide galvanic isolation between the various supplies.
The sheet metal racks 22 through 28 are in three parts, hinged laterally:
- a basic element with openings at the top and bottom, possibly closed off by blanking plates, - a frame pivoting 90 to the left relative to the basic element and adapted to receive a card-frame to european standards, - a glazed door pivoting 90 to the left relative to the frame.
The glazed door makes it possible to observe the various indicators on the ~ront panels of the electronic circuit boards (input and output states).
These racks may be joined together to suit the size o~ the application ~number o~ inputs/outputs). The openings in the top and bottom provide ~or inter-rack wiring.
Racks 25 through 28 accommodating the terminal blocks Eor the connections to the sensors and the actuators comprise only the basic element and a hinged solid door ~the pivoting ~rame is not used~.
The connections between the central unit UC and ~he u~er part arQ shown in ~icJure 2, in whiGh are seen 2~i three separate buses: a microprocessor bus ~M, an inter-rack bus BIC and input/output buses BES.
The central unit part, shown on the le~t, comprises a processing unit part, a display element and an interface module between the buses BM and BIC.
The processing unit part comprises a micro-processor unit MPU, a random access memory (RAM) board (this memory can be read and written), a system EPROM
board and a user EPROM board, a board for dialogue with a development system and an optional board for dialogue with another automatic controller.
The boards constituting the processing unit ~ay be com~ercially available boards, ~or example, the only constraints applying to the choice of these boards being as follows: single 5 V supply, no self-induction coil and low value capacitors (< l00 ~F).
In practice commercially available boards using recent technology will meet these conditions.
To give an example, the automatic controller under consideration is e~uipped with industrial grade (-40C to +85C) boards to the Eurocard format (100 x 160 mm~ and the National Semiconductor CIMsUS
standard, using the NSC 800 microprocessor (C~IOS
technology):
- microprocessor (MPU) board - CIM 804, - system RAM board - CIM 108, system EPROM board - CIM 10Q, - user EPROM board - CIM 100, - development system dialogue board (RS232C serial link and current loop) - CIM 201, - (optional) inter-controller dialogue board (identical connection to previous connection) - CIM 201.
In principle the 5ystem EPROM contains the various pro~rams needed for the automatic controller to unction: link with a development system, automatic controller language interpreter, test program, etc.
The MPU and RA~ boards are in practice combined in an MPU + RAM cartridge, the EPROM boards in an EPRO~
cartridge and the dialogue boards in a DIA module.
In the example under consideration programs can be written and debugged on the surface using the MERLIN
GERIN CDE 1000 programming console with which the automa~ic controller is compatible at connection and dialogue (BD) level. The programming languages used are the same as those used by MERLIN GERIN for its PS range of automatic controllers, namely: GRAFCET, SCHEMA RELAIS
and ASSEMBLEUR PB. The source program (GRAFCET, SCHE~tA
RELAIS or ASSEMBLEUR) is entered ~rom the keyboard of the CDE 1000 console. Once all of the source program has been entered it is compiled to obtain a runnable program (understandable by the automatic controller) which is transferred into the EPROM in the "EPROM
CARTRIDGE" module through a cable connected to the console. The "EPROM CARTRIDGE" is then plugged into:
- the automatic controller at the surface for preliminary tests, - (in its final version) the automatic controller down the mine once the program has been fully tested on the surface.
If the program is not free of bugs the "EPROM
CARTRIDGE" can be erased in the known manner by exposing it to UV radiation.
The display unit (VISU in the diagrams) controls a block of two 7-segment displays which indicate in coded form mal~unctions o~ the system noted by the processing unit. They can also be used by the user program (for example to display the current stage or the reason or a halt - in coded Eorm) or by the system pr~ram ~o verify ~orr~ct execution of khe user program.
By vir~ue o~ ~ne adv~nt~geous ch~racteristic oE
the invention the VISU unit, connected directly to the microprocessor bus, continues to function even in the event of a breakdown on the user part.
The inter-bus interface module MIB provides isolation between the user part and the system part, an essential characteristics of the invention. Thus a breakdown affecting a rac~ controller or an input/output module will not disrupt operation of the microprocessor module. As the display unit (and any associated test unit) is (or are) connected directly to the microprocessor bus, without passing through the bus inter~ace module and without any connection to the user part, the system maintenance and fault indication functions are preserved whatever units are faulty.
The MIB module also handles management (possibly including temporary storage) of the various signals necessary to the user part (input/output bus) and address decoding for selecting rack controller modules.
A self-monitoring or "watchdog" function is advantageously provided. Its theory of operation is as follows: a monostable has to be reset every 200 ms at most or it de-energises a relay coil 50 shutting down the controlled process. The automat under consideration here is advantageously equipped with two "watchdogs":
- one driven by the system software (invalid execution of instructions from the microprocessor de-energises the corresponding relay);
- the other driven by the user program: in this case the user must include periodically in his program the instruction to reset the monostable. Thus any malfunctioning o~ the user program will de-energise both "watchdog" relays.
There is also a synchronisation and clock board (not shown) whose ~unction is to generate and distribute 3S all the clock signals n~cessary to the processing unit ll and the various modules. In particular, it produces a synchronisation and power supply combined signal fed to the remote multiplexed input modules. This is preferably an alternating current signal in which one cycle is periodically nulled (see figure 7).
As previously stated, the user part comprises an inter-rack bus BIC which terminates at a rack control board CCl, CC2 or CC3 (of type ID 15) in each of the racks 22, 23 and 24.
10Although the microprocessor bus BM is short so that signals can traverse it quickly, the inter-rack bus BIC featuras a reduced number of conductors and the signals that it carries are slowed down. There is also in each rack an input/output bus BES already mentioned - 15and, at the rack output, the BC or BND output buses (see figure 1) that are possibly connected through intrinsically safe interface modules ISI.
The various signals that can travel on the buses are divided between:
- data lines denoted DO through D7, - address lines denoted AO throu~h A3 corresponding to a selection of functions or denoted A4 through A7, - a read/write line denoted R/W, and - a data acknowledge line and a dedicated line o rank in each rack of rank n.
The schematics of the various modules are self-explanatory and will be described only in outline.
Interconnect is standardised. All slots in a rack 22, 23 or 24 are wired identically and can accommodate any type of input/output module.
All input/output modules have an identification code specific to their type. This code is read by the processing unit. When the user software is being written in the langua~e o~ the automatic controller, the u~or will have to ~in~ khe pQsitiQn o~ th~ inpuk and output modules in the racks and will therefore have to produce a configuration table. The processing unit compares the code as read at the various slots with that recorded in the table. If these are not identical for any slot (board missing, board failure or wrong type of board), the user program stops, the "watchdog" stops the process and a code is shown on the displays.
Inputs are acquired synchronously with the clock signals and the processing unit then exploits the redundancy of the acquired data to form a working memory image used by the user program. This memory image is refreshed as and when the user sees fit by means of an appropriate instruction in the automatic controller language.
Figure 3 is a block diagram of a rack control board CCl, CC2 or CC3. This board principally incorporates a bidirectional buffer memory MTB inserted in the data bus D0-D7, a second buffer memory MTF at which the function select lines A0-A3 terminate, a board self-test module MAC connected to lines B0-B7 and to lines A0-A3, and a module MSC for decoding the number of a given board to which are connected lines A4-A7 and a rack controller select line SCC. The outputs of this board comprise data lines D0-D7, function select address lines A0-A3 and lines N selecting boards in the corresponding rack (8 or 15 wires).
In each rack this board isolates and te~porarily stores signals intended for the 15 (or eight) slots that lt can address (functions similar to the bus interface module).
This board or module also has a self-monitoring role in relation to the input/output bus distributed to the 15 slots.
It is used to veri~y correct ~unctioning o~ the input/output ~us and the link connecting it to the bus interface module MIs.
Thus any fault on the input/output bus of a rack is signalled to the processing unit and does not affect the functioning of the other racks.
Each module CC1, CC2 or CC3 controls a subgroup of input/output boards. There are various types of input-output module: parameter adjustment modules PAR, multiplexed digital input modules ENM adapted to be connected to remote multiplexed digital input modules EDM, high-speed digital input modules ENR (direct connection) and digital output modules SN.
Figure 4 is a block diagram of an input/output PAR module occupying two slots in a rack (see figure 1) for in situ adjustment of parameters such as: time-delays, triggering thresholds, counter/downcounter set points, operating modes, etc.
A module of this kind comprises at least one thumbwheel RC associated with each parameter to be adjusted (in this instance eight pairs of thumbwheels permitting adjustment of eight parameters to values between 00 and 99). This module preferably further comprises a plurality of TTL inputs (in this instance 16 inputs denoted E0 throu~h E~) available on a terminal block in one of the racks 25 throu~h 28. The inputs are 2S designed to be connected to switches inside the auto~atic controller or to be shunted at the terminal block by means of straps. The inputs are essentially intended Eor maintenance and emergency process control.
The figure 4 PAR module principally comprises, in addition to the thumbwheels RC, a decoder DEC
connected to the select lines A0-A3 and an addressing line Erom a logic module MLl to which ~re routed read and rack number lines R and NR; the decoder DEC is also connoctod to the ~humbwheels, a buf~er memory MTRC
~5 connected to the ~humbwheels by a thumbwheel read bus BRC, and to the data bus D0-D7, and multiplexing unit MP
connected to the data bus D0-D7, to the TTL inputs denoted ~0 through EF to board type lines TC, to the lines A0-A3 and to an output line from a second logic module ML2. Each of the multiplexing units provides two signals selected rom two groups each of four signals.
By pressing a pushbutton BP and through the intermediary of a bistable BL the user can read the values set on the thumbwheels at any time he wishes; these values are recognised immediately and substituted for the values previously read. A PAR module of this kind is a special input module by means of which a user can enter data himself, the thumbwheels themselves indicating the status of the inputs that they constitute.
lS As will shortly emerge and in accordance with one advantageous embodiment of ~he invention, the other input/output modules are equipped with display devices -preferably indicator lamps - adapted to be controlled by the processing unit itself so as to display at this module the state of the inputs/outputs connected to this module as it is seen by the processing unit. There are preferably display devices adapted to display the state of each input/output, according to whether the associated actuator or sensor is in the one or the other of its basic conditions, or whether the connecting line to the actuator or the sensor is short-circuited or open-circuit (see below in relation to igure 10).
It is important to note that as these lamps are controlled directly by the processing unit and not through wiring it is certain that the state of the lamps corresponds to the state as "seen" by the processing unit; the state of each input (or output) is regularly (for example: every 1~0 ms) sampled, and the result of thi~ sampling is stored in a memory image that can be rcad a~ any ~ime.
.: . ~ , -.
~'9:~2~
Figure 5 is a block diagram of a multiplexed digital input board or module ENM. Each module of this type, adapted to manage eight remote inputs, is connected by a four-wire remote input bus BED
(comprising two telephone pairs, for example) to a remote module EDM (schematically represented in figure 7) providing for successive scanning of eight sensors C
using a circuit represented schematically in figure 6.
The connection with the remote block EDM and to the sensor C is o~ intrinsically safe level Ia and may be as long as 4 km, for example.
The ENM board principally comprises two shift registers RDl and RD2 followed by two multiplexers MPl and MP2 connected to line A0 and two latches Ll and L2 between which are connected in reverse parallel light-emitting diodes DEL constituting indicator lamps of different colours, green and red, for example.
The register RDl receives the signals from the associated remote module through a diode link LD and a clock signal CLK; one of its outputs is fed to the other register RD2, which also receives the signal CLK. Some inputs of the multiplexer MP2 may be ear~hed or connected to 5 V depending on the sattin~ of switches serving to indicate the type of microprocessor board.
The read line R, board number line N and write line W
are combined by logic devices whose outputs are fed either to the multiplexers or ~o the latches. The pairs of diodes DEL are used to display four different indi~ations according to whether positive or negative direct current or positive or negative rectified alternating current is applied to them.
The four wires oE the remote input buf~er BED
carry the data signals from the remote module EDM and a power supply ahd synchronisation signal ~already mQnti~ned hereinabove) from the automakic controller.
Each sensor C is connected to the associated EDM module by two wires.
As schematically represented in figure 7, the module EDM principally comprises a device RAS for rectifying the incoming power supply and synchronisation signals followed by an optocoupler link DPZ for detecting passages through zero the output of which is fed to a monostable MS and, like the clock signals CLK, to a counter CP16 designed to react through cycles of 16 pulses and to a decoder DEC10 adapted to react through cycles of 10 pulses. De-energisation of the monostable resets the counter and the decoder. For lines numbered 1 through 8 the decoder sucessively energises each of the sensors Cl through C8 the responses from which appear between output lines forming part of the bus BED.
A pair of modules ENM and EDM makes it possi~le to sample the inputs every 180 mns, but as already specified, the state of each input can be read at any time from the memory image.
For more frequent sampling, every 20 mns for example, it is possible to use a high~speed digital input module ENR as schematically represented in figure 8, with separate links to each of the associated sensors ~.
The link to the sensors is, as previously, of intrinsic safety level Ia and may be as long as 4 km, for example. The states of the various inputs are read simultaneously.
This module ENR principally comprises a buffer memory MTLS, a multiplexer MPLS and a display device ALS, all three equipped with select logic and connected to the data lines D0-D7, to the function select lines A0-A3 and to the board select lines N. Associated with th~ display ~ViG~ ALS is a set o~ front panel lamps ,~ L6 VFA, similar to the diodes DEL in figure 5, for example, while associated with the multiplexer MPLSD is a board type switch ITC. The buffer memory ITLS is connected to each of the sensors C by a galvanic isolation opto-coupler OC.
A digital output module SN is schematicallyrepresented in figure 9. It is used to control eight actuators ACT through galvanic isolation opto-electronic couplers COE (as the actuators are supplied with power from a different power supply, there is no mixing or interaction at this level). The actuators may be of the electromechanical or solid-state relay type; their control connections are intrinsically safe.
This module SN principally comprises a multi-plexer MLS equipped with select logic connected to thelines BO-B7, AO-A3 and N, to board type switches ITC and to couplers COE already mentioned, a select logic module LS connected to the lines N and AO-A3, a latch MRT
connected to the lines DO-D7 and to a select line Sl from the module LS and a display module MAF connected to the lines DO-D7 and to a select line S2 from the module LS, and controlling the front panel lamps VFA similar to those o~ figure 8.
It may be made possible to ~orce individually the excitation of the actuator, by means of a strap (not shown). Any such action is seen by the processing unit and made available to the user program in the working memory image: thus when writing his program the user can place the process in a fall~ack position cancelling the effects of any unacceptable forcing.
As for the input boards, each output state is displayed on the SN board at the automatic controller with one oE the two lamps lit continuously or intermi~t~n~ly. -.~ In ~he ca~e o~ ~oth sensor~ and ac~ua~or~, the lines connecting the~ to the remainder of the automatic controller are, in accordance with one advantageous characteristic of the invention, controlled by the circuit of figure 10.
A sensor C comprises an element EC movable between two fundamental positions 1 and 2 and two diodes Dl and D2 connected in reverse directions in two parallel branches linking the connecting llnes to an intrinsically safe alternating current supply U disposed in an associated input module. One of these connecting lines preferably comprises a photo-electronic detector formed by two light-emitting diodes connected in reverse parallel.
There appears across a resistor R provided in one of the lines in said associated module an alter-nating current voltage that i5 rectified positively in the even~ of contact at 1, rectified negatively in the event of contact at 2, of zero value in the event that one of the connecting lines is cut, or identical to the voltage delivered at U in the event of short-circuiting of the connecting lines. It is easy to associate with each of these forms of the voltage a specific mode of lighting the lamps on the front panel of e~ch input of output board (see figure 5 in particular).
In other words, in accordance with the invention the current in the resistor R is sampled on each half-cycle synchronously with the power supply so that the four aforementioned cases are obtained.
It will be noted that the invention makes it possible for the user program not to know the physical input~output addresses (internal real address of the registers in the input and output modules). The program addresses itsel~ to a workin~ memory ima~e situated in the RAM. ~rh~ sys tem 50Etware:
~ ac~uire~ all input skakqs synchronou~ly wi~h the clock signals and then, if it recognises a state corresponding to a fault (line cut or short-circuited), waits for the next acquisition cycle before validating the information (this makes it possible to avoid a change of sensor state being interpreted as a fault), - reads the outputs to test for any forcing, - processes all this information and controls the lamps appropriately.
The results of this processing are transferred into the working memory image by the system software only when it reads the refresh instruction RAFR in the user program.
It goes without saying that the foregoing description has been offered by way of non-limiting illustrative example only and that numerous variations may be proposed by those skilled in the art without departing from the scope of the invention, in particular regarding the number of inputs/outputs controlled by each board or the number of boards placed under the control of each rack control board ~dependent on the technology employed), the structure of the connecting buses and the detailed structure oE the various boards.
An automatic controller in accordance with the invention is in practice adapted to utilise a wide variety of input/output boards.
Claims (7)
1. A centralised controller including a single processing unit for controlling actuators depending on the state of sensors, comprising:
a set of adjacent board racks, a central unit housed in said set of racks including a plurality of constituent units, one of which is said single processing unit, a first bus within said central unit connecting said constituent units to each other, a modular user part also housed in said set of racks and comprising a plurality of input/output boards respectively connected to sid actuators and to said sensors, the number of said input/output boards in said plurality being selected depending on the number of said actuators and sensors, said plurality of input/output boards being distributed in at least two board groups, each of said group being located in one rack in said set of racks which is specific to said group, a rack board and rack bus for each said group in said specific rack, said rack bus connecting each said input/output board in said group to said rack board, a second bus connecting all the said rack boards to each other, and a bus interface board connecting said first bus to said second bus.
a set of adjacent board racks, a central unit housed in said set of racks including a plurality of constituent units, one of which is said single processing unit, a first bus within said central unit connecting said constituent units to each other, a modular user part also housed in said set of racks and comprising a plurality of input/output boards respectively connected to sid actuators and to said sensors, the number of said input/output boards in said plurality being selected depending on the number of said actuators and sensors, said plurality of input/output boards being distributed in at least two board groups, each of said group being located in one rack in said set of racks which is specific to said group, a rack board and rack bus for each said group in said specific rack, said rack bus connecting each said input/output board in said group to said rack board, a second bus connecting all the said rack boards to each other, and a bus interface board connecting said first bus to said second bus.
2. The centralised controller of claim 1 further comprising a defect display unit connected to said first bus within said central unit.
3. The centralised controller of claim 1 wherein at least one input/output board in one said board group is provided with a display device for each said actuator or sensor connected by two lines to said input/output board, each display device having four different states respectively corresponding to one or the other of two predetermined states of associated said actuator or sensor, a cut in anyone of said two lines and to a short-circuit between said two lines, each said state of each said display device being controlled by said central unit.
4. The centralised controller of claim 3 wherein each said display device is a pair of light emitting diodes of different colours connected in reverse parallel, said four states corresponding to one and/or the other of said light-emitting diodes emitting light or not.
5. The centralised controller of claim 1 wherein at least one of said input/output boards is a multiplexed digital input board connected to associated sensors through a remote multiplexed digital input module, a four-wire connection being provided between said multiplexed digital input board and said remote multiplexed digital input module.
6. The centralised controller of claim 1 wherein said modular user part further includes at least one parameter adjustment input board comprising thumbwheels and a pushbutton for having said thumbwheels scanned by said central unit.
7. Automatic controller according to claim 3 wherein at least one of said input/output boards is connected by two lines to an external unit comprising two parallel branches respectively comprising diodes connected in reverse parallel and a mobile element movable between two fundamental positions, where it closes one or the other of these branches, such controller further comprising an alternating current voltage source connected to said lines, and a resistive component provided in one of these lines, the potential across this resistive component being transmitted to said input/output board as a signal representing the position of the mobile element and the state of said lines.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8511.861 | 1985-08-02 | ||
| FR8511861A FR2585611B1 (en) | 1985-08-02 | 1985-08-02 | MODULAR PLC, PREFERABLY PROGRAMMABLE, ESPECIALLY FOR MINING MACHINERY |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1291246C true CA1291246C (en) | 1991-10-22 |
Family
ID=9321916
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000514710A Expired - Fee Related CA1291246C (en) | 1985-08-02 | 1986-07-25 | Modular automatic controller, preferably programmable, in particular for mining plant |
Country Status (15)
| Country | Link |
|---|---|
| EP (1) | EP0211766B1 (en) |
| JP (1) | JPS6241893A (en) |
| KR (1) | KR870001907A (en) |
| CN (1) | CN1011265B (en) |
| AT (1) | ATE51967T1 (en) |
| AU (1) | AU588899B2 (en) |
| CA (1) | CA1291246C (en) |
| DE (1) | DE3670385D1 (en) |
| ES (1) | ES2000821A6 (en) |
| FR (1) | FR2585611B1 (en) |
| HU (1) | HU197244B (en) |
| IN (1) | IN167796B (en) |
| PL (1) | PL152133B1 (en) |
| YU (1) | YU137286A (en) |
| ZA (1) | ZA865312B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3143465A4 (en) * | 2014-05-11 | 2018-01-31 | Howden Alphair Ventilating Systems Inc. | Modular controlling system for ventilation equipment and methods of using the same |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2607274B1 (en) * | 1986-11-25 | 1989-03-31 | Telemecanique Electrique | INPUT MANAGEMENT CIRCUIT, IN PARTICULAR FOR A PROGRAMMABLE PLC |
| EP0547259B1 (en) * | 1991-12-17 | 1996-04-17 | Siemens Aktiengesellschaft | Circuit for securing the operation of a computer-controlled apparatus |
| WO2008016977A2 (en) * | 2006-08-01 | 2008-02-07 | A.O. Smith Corporation | Interface cord and system including an interface cord |
| CN103885378A (en) * | 2013-12-13 | 2014-06-25 | 常州联力自动化科技有限公司 | Intrinsic safe programmable mining controller and control system |
| CN115081578B (en) * | 2022-06-08 | 2023-11-03 | 华能核能技术研究院有限公司 | Fuel ball counter signal processing system, method, device and electronic equipment |
| CN117967307B (en) * | 2024-04-01 | 2024-06-07 | 枣庄矿业集团新安煤业有限公司 | Data processing method for remotely controlling rotation adjustment mining of coal mining machine |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2067307A (en) * | 1979-12-21 | 1981-07-22 | Pcl Reprographic Eng Services | Improvements in Apparatus for a Method of Diagnostic Testing of Electrically Controlled Machinery |
| FR2549988B1 (en) * | 1983-07-06 | 1986-03-21 | Semy Engineering Sarl | PROGRAMMABLE INDUSTRIAL PROCESS CONTROLLER WITH INDUSTRIAL NOISE |
| GB8517155D0 (en) * | 1985-07-05 | 1985-08-14 | Qualter Hall & Co Ltd | Programmable logic controller system |
-
1985
- 1985-08-02 FR FR8511861A patent/FR2585611B1/en not_active Expired
-
1986
- 1986-07-16 IN IN547/MAS/86A patent/IN167796B/en unknown
- 1986-07-16 ZA ZA865312A patent/ZA865312B/en unknown
- 1986-07-18 AU AU60357/86A patent/AU588899B2/en not_active Ceased
- 1986-07-25 CA CA000514710A patent/CA1291246C/en not_active Expired - Fee Related
- 1986-07-30 HU HU863233A patent/HU197244B/en not_active IP Right Cessation
- 1986-07-31 YU YU01372/86A patent/YU137286A/en unknown
- 1986-07-31 KR KR1019860006293A patent/KR870001907A/en not_active Ceased
- 1986-08-01 CN CN86105656A patent/CN1011265B/en not_active Expired
- 1986-08-01 JP JP61181801A patent/JPS6241893A/en active Pending
- 1986-08-01 AT AT86401734T patent/ATE51967T1/en not_active IP Right Cessation
- 1986-08-01 EP EP86401734A patent/EP0211766B1/en not_active Expired - Lifetime
- 1986-08-01 DE DE8686401734T patent/DE3670385D1/en not_active Revoked
- 1986-08-01 ES ES8600818A patent/ES2000821A6/en not_active Expired
- 1986-08-01 PL PL1986260884A patent/PL152133B1/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3143465A4 (en) * | 2014-05-11 | 2018-01-31 | Howden Alphair Ventilating Systems Inc. | Modular controlling system for ventilation equipment and methods of using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0211766B1 (en) | 1990-04-11 |
| PL152133B1 (en) | 1990-11-30 |
| FR2585611B1 (en) | 1987-11-20 |
| ZA865312B (en) | 1987-03-25 |
| FR2585611A1 (en) | 1987-02-06 |
| KR870001907A (en) | 1987-03-28 |
| YU137286A (en) | 1988-12-31 |
| PL260884A1 (en) | 1987-03-23 |
| HUT43520A (en) | 1987-11-30 |
| ES2000821A6 (en) | 1988-03-16 |
| ATE51967T1 (en) | 1990-04-15 |
| AU588899B2 (en) | 1989-09-28 |
| IN167796B (en) | 1990-12-22 |
| DE3670385D1 (en) | 1990-05-17 |
| EP0211766A1 (en) | 1987-02-25 |
| AU6035786A (en) | 1987-02-05 |
| CN86105656A (en) | 1987-03-18 |
| CN1011265B (en) | 1991-01-16 |
| HU197244B (en) | 1989-03-28 |
| JPS6241893A (en) | 1987-02-23 |
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