FR2585135A1 - Method and device for determining perturbations in the functioning of an industrial process controlled by a set of relays - Google Patents

Abstract

The device comprises inputs intended to be connected to the particular points in the sequence to be monitored; means 45 for combining the signals from the said inputs into a combination signal intended to change state when the perturbation occurs; means 13 for sampling and recording the signals appearing at the said inputs until the state of the perturbation combination signal changes; and means 14 for off-line reading of the recordings in order to determine the particular input which is causing the perturbation.

Description

 The present invention relates to the detection and localization of operating anomalies in an industrial process and relates more particularly to the detection and localization of such anomalies in a device whose various operations are controlled by relays.

 In relay excitation chains. the interactions cause the relays to cascade down, which makes it difficult to troubleshoot intermittent faults due in particular to the fact that the response time of a relay is relatively short, of the order of approximately tOms.

 The monitoring of the functioning of industrial processes such as for example the operations of a continuous annealing line from sheet metal to coil is generally ensured by means of magnetic recorders with several channels whose essential advantage is a wide band busy (O at 20 KHz).

 However, magnetic recorders require the use of trigger signals generated by a source external to the device.

 The magnetic tapes are subject to wear due to the succession of erasing and writing cycles.

 The average lifespan of a magnetic strip is considered to be 8 hours.

 It is also possible to use pen recorders, the scrolling speed of which can be adjusted within a large range of between 1 mm / min and 125 mm / sec, these recorders being able to be further controlled remotely.

 However, pen recorders also have a number of drawbacks.

 They have insufficient resolution and precision.

The scrolling of the paper is continuous which leads to a significant consumption of paper
They cannot be triggered at a specific time.

 Therefore their use is limited to monitoring slowly varying signals.

 The invention aims to overcome the drawbacks of recording devices of the prior art by creating a device for determining and recording disturbances which is extremely easy to use, which operates autonomously and which has increased resolution compared to known system.

 It therefore relates to a method for determining disturbances in the course of an operating sequence of an industrial process controlled by a set of relays, characterized in that it consists in establishing the remarkable points of the sequence to be checked in which the disturbance occurs, to define a combinational signal of the various inputs, intended to change state at the time of the disturbance, to sample and record the signals appearing at the remarkable points until the change of state of the combinative signal and to exploit time-delayed recordings to determine the remarkable entry that is causing the disturbance.

 The invention also relates to a device for determining disturbances intended for the implementation of the method defined above, characterized in that it comprises inputs intended to be connected to the remarkable points of the sequence to be checked, means for combining the signals of said inputs into a combinational signal intended to change state at the time of the disturbance, means for sampling and recording the signals appearing at said inputs until the change of state of the combinational disturbance signal and means for reading time-delayed recordings to determine the remarkable input which is causing the disturbance.

The invention will be better understood with the aid of the description which follows, given solely by way of example and made with reference to the appended drawings, in which
Fig. 1 is a schematic view of a sheet annealing line to which the device according to the invention is applied.

 Fig. 2 is an electrical diagram of part of the relays controlling the installation of FIG.

1 to which the device according to the invention is connected,
Fig. 3 is a block diagram of the recording and reading device according to the invention;
Fig. 4 is a diagram showing a type of logic intended to generate a fault signal.

Fig.5 is a block diagram of an alternative embodiment of the means for recording and detecting changes of state of the diagram of the
Fig.3; and
Fig.6 is a schematic representation of the internal architecture of the device according to the invention.

 In Fig. 1 is a schematic representation of a sheet annealing line comprising two supply coils 1, 2 ,, a welding machine 3, disposed downstream of the coils 1 and 2, on the path of the sheet T, a first series of rollers s on which a first sheet reserve 5 is formed, a zone 6 of continuous annealing, a second series of rollers 7 intended to constitute a second sheet reserve 8, a flying shear 9 disposed at the outlet of the second sheet reserve 8, and output winders 10 and 11 intended to receive the sheet in turn and allow the alternating evacuation of the coils formed.

 The various organs of the line are trained by. electric motors not shown, the operation of which is controlled by relays.

 The interconnections of these relays are shown in Fig. 2 to which we will now refer.

 The circuit of FIG. 2 is a partial representation of the relay assembly controlling the operation of the line in FIG. 1.

 It includes a first relay intended to indicate that the winder N 2 of the line. Fig. t driving the coil 11 is ready to operate.

 This relay A is connected between two live electrical conductors via five contacts Ep1, Ep2, Ep3, Ep4, r A in series.

 The contacts Ep1 to Ep4 are the contacts which give the winding condition N 2 ready.

 Contact IA is a contact equivalent to an interlock on relay A.

 In parallel with relay A and its contacts Ep1 to IA, a relay B is connected in series with six contacts AML1, AML2, AML3, AHL4, AML5 and IB.

 Relay B is the line authorization relay.

 The AML1 to AML5 contacts are operating condition contacts.

 Contact IB is the interlock contact on relay B.

In parallel to the two previous relays is connected a C relay in series with four contacts
Te1, Te2, Te3, and Ic.

 Relay C is the relay intended to indicate that a transfer is in progress.

 The contacts Te1 to Te3, are contacts of transfer conditions.

 Contact Ic is an interlocking contact on relay c.

 When the operation of the part of the corresponding line is faultless, all the contacts associated with the aforementioned relays are closed.

The transfer fault signal consists of a logical combination of the signals from relays A,
B and C.

In parallel, relay C and its contacts is also connected to a relay D associated with a contact.
DT of transfer failure.

The anomaly detection and localization device according to the invention designated on the
Fig. 2 by the reference 12 comprises a number of inputs among which the inputs E1 to E16 are each connected at an intermediate point between two contacts or else at an intermediate point between a contact and a corresponding relay.

 The other polarity of each input of the device 12 is connected to a common point under voltage.

The device 12 comprises a recording device 13 and a delayed reading device 14 which will be described in more detail below with reference to FIG. 3.

 The recording device 13 has analog inputs 15 connected to an analog voltage source 16 and connected to an analog-digital converter 17.

 The analog-digital converter 17 is connected to a circuit 18 for comparison with a threshold determined by a potentiometer 19 and a selector 19a for logical decision with respect to this threshold.

 This circuit is in turn connected to a display device 20 comprising a logic output 21 on which are intended to appear fault signals contributing to establishing the logic equation of the combinational signal of the various analog inputs of the circuit. The display device 20 comprises as many light-emitting diodes 20 as there are voltage sources to be monitored.

 The analog-digital converter 17 is controlled by a programmable time base circuit 22 which also controls an exclusive OR circuit 23 whose inputs are materialized by an input connected via an optical isolation module 24 to a source 25 to monitor. There are as many isolation modules as there are inputs. Each isolation module 24 is advantageously constituted by a voltage converter with phototransistors associated with light-emitting diodes 24a.

 The other input of the OR circuit 23 is connected to a logic state inverter 26.

 To the exclusive OR circuit 23 is connected a display device 27 with light-emitting diodes 27a at the rate of one per input to be monitored.

 The analog-digital converter 17 and the logic circuit 23 have outputs connected to a device 28 for detecting changes by comparison and for managing the associated time intervals.

 At the output of the device 28 is connected a memory 29 for storing the status information of the installation to be monitored.

 The circuit 28 for detecting changes and managing the time intervals is connected to a device 30 for timed stopping of the recording, an input of which is intended to receive the fault signal corresponding to a disturbance.

 Another input of the device 30 is connected to a switch 31 for determining the direction of variation of the fault signal (rising or falling edge).

 The timed stop device 30 is possibly associated with a filter.

 To the memory 29 is connected an addressing circuit 32 controlled by a time base circuit 33 with which is associated a contact 34 for initializing the read operations.

 The time base circuit 33 also controls a device 35 for the start and end of reproduction intended to control a relay 36 for actuating a contact 37 which is in the supply circuit of a graphic recorder, not shown. .

 The addressing circuit 32 is associated with a contact 38 for controlling the addressing of a previous interval and a contact 39 for controlling the addressing of an interval according to the current interval.

 The memory 29 is also connected to a digital-analog conversion and multiplexing circuit 40 as well as to a display circuit 41 with light-emitting diodes 41a.

 Some of the outputs of the digital-analog converter circuit 40 and the outputs of the display circuit 41 are connected to a switch X2 itself connected to a recording device not shown.

 The other outputs of circuit 40 are directly connected to the recording device.

 By way of example, the device in FIG. 3 has twelve analog inputs and thirty two logic inputs.

 In the connection example shown in FIG. 2 sixteen of the thirty two logic inputs are used to monitor the operation of the machine of FIG. 1.

The operation of the apparatus of FIG. 3 will be described by taking, for example, the monitoring of the operation of the sheet annealing line of the
Fig. 1.

 The constitution of a fault signal will now be described with reference to the example of logic circuit shown in FIG. 4.

 This circuit is constituted by an AND gate 45 with three inputs, two of which are connected to inverters 46 and * 7.

The inputs of the inverters 46 and 47 respectively constitute the inputs E5 and E11 of the device according to the invention, connected to the relay assembly of FIG. 2, and the third door entrance
ET 45 is input E15 for this device.

 The arrangement of FIG. 2 is designed from my niece that all monitored contacts are closed during faultless operation.

 Referring to Fig.4 we see that the input E5 is then in state 1 converted by the inverter 46 to 0 logic appearing at the corresponding input of the gate 55.

 This situation indicates that the winder N-2 intended to drive the reel 11 is ready.

 The input E11 also in state 1 converted by the inverter 47 into a logic 0 appears at the second input of the AND gate 45.

 This corresponds to an authorization to run the line in FIG. 1.

 Finally, the input E15 is at state 1 corresponding to a transfer situation in progress.

 Signals 0,0 and 1 are therefore applied to the inputs of AND gate 45.

 The circuit of FIG. 4 materializes in the present case a part composed by the operator of the apparatus of FIG. 3 including three of the thirty two logic inputs would constitute the inputs E5, E11 and E15.

The transfer requested by the manufacturing operator consists of
- start the empty reel and synchronize it with the speed of the other
- cut the tape on the fly
- direct the sheet metal strip towards the empty reel.

 The "transfer in progress" information is a signal stored in memory from the operator's request until the end of switching from one reel to the other.

 The situation of the inputs E1 to E16 of the circuit is reflected by the state of the light-emitting diodes 24a.

 The signals of the inputs E1 to E 16 are applied via the optical isolation modules 24 of the circuit to the exclusive OR circuit 23 and are subject to sampling by the programmable time base circuit 22 at a frequency of for example.

The output signals of the circuit 23 which translate the instantaneous situation of the inputs E1 to
E16 and consequently of the line of FIG. 1, the operation of which is monitored, are applied to the circuit 28 for detecting change by comparison and for managing the associated time intervals.

 As long as the signals coincide with those received by the circuit 28 during the previous sampling, these signals are kept in the memory 29.

 It may happen that a defect is noted at a frequency which can vary from several hours to a few days, this defect consisting of a line stop during the transfer from the winder N-1 to the winder N'2.

 The study of all of the relays controlling the operation of the line shows that three relays, namely relays A, B, C, in the diagram in FIG. 2 are involved in the defect.

In addition to the excitation chains of each of the aforementioned relays formed by the contacts Ept a IA,
AML1 to they B and Te1 to Ic respectively there is an interlock namely
- a line stop signal (fallout of
Relay A) clears the transfer memory;
- an N2 winder signal not ready (re
Relay B) stops the line if the
N-2 rolling machine is in service which corresponds
lays in a normal situation
causes a transfer fault if a trans
fert is in progress, which corresponds to a
anomaly;;
- a transfer failure signal (fallout of
relay C) deactivates the run authorization
of the line,
deactivates the N-2 ready rewind signal.

 The three relays A, B, C fell out without knowing either the order or the reason for the fault.

 In the example considered, the signal from the logic equation is summarized at the "transfer fault" input which is used for signaling on the console of the manufacturing operation.

This signal is applied to input E16 of the arrangement of FIG. 2. This input is connected directly to the "Fault" input of the device of the
Fig.3 with a rising edge.

 The device therefore detected a transfer fault.

 It is then noted that the origin of the fault is the opening of the contact Ep2 because the input Ep1 has remained supplied while the inputs Ep2 to Ep5 have gone to zero.

 This observation takes place using the light-emitting diodes 41a of the optical isolation module.

 The fallout of relay A resulted in that of relays B and C due to the opening of contacts IB and Ic in a given time, around 20ms.

 Under the fault conditions, the logic equation reflected by the circuit in Fig. 4 can be stated: loss of the winding signal N2 ready and of the line running authorization signal during a transfer.

In Boolean notation this translates to the expression ABC;
The output signal X of gate 45 of the
Fig. 4 is in fact the complement of the desired signal and it goes to O when the condition AB C is fulfilled.

 It can therefore be connected directly to the fault input provided that the edge selector 31 is set to the appropriate position (falling edge).

 Referring again to FIG. 3, it can be seen that the appearance of a fault signal at the fault signal input of the circuit 30 causes the latter to send to the circuit 28 a delayed recording stop signal.

 After stopping the recording, the device 27 and the light-emitting diodes 27a display the values recorded at the time of the fault.

 The pushbuttons 38 and 39 associated with the addressing circuit 32 make it possible to display on these same components the state which differs from the normal state by at least one input.

 The switch 34 makes it possible to reproduce the recording graphically by controlling, via the time base circuit 33, the circuit 35 for the start and end of reproduction, which in turn causes the relay 36 ensuring closing. of the power supply circuit of the recorder not shown.

 After all the values used have been recorded in this way by a graphic copy, the device can be reset to zero and thus be replaced in the same conditions as when powering up.

 The operation of the apparatus of FIG. 3 has been described assuming the use of sixteen of its thirty two digital inputs.

The part of the apparatus intended to process the signals applied to its analog inputs 15 operates in a similar manner, after conversion of the input signals by the analog-digital converter 17 controlled by the time base circuit 22 which provides a signal sampling every 5 ms for example
Furthermore, for the copying of the data stored in the memory 29, these are converted into analog form by the digital-analog converter 40.

 The circuit shown in FIG. 5 is a variant of the part of the circuit in FIG. 3 intended to record the detection of changes in the monitored input signals.

 This circuit comprises four logic circuits 50 to 53 with eight inputs each designed so that their respective outputs change state each time one of their eight inputs changes state.

 These circuits 50 to 53 are in turn connected to a circuit 54 for managing the time intervals and for storage similar to the circuit 28 of the circuit in FIG. 3.

 The management circuit 54 is associated with a time base circuit 56 ensuring the sampling of the output signals of the circuits 50 to 53. The circuit 54 is connected to a memory 56 similar to the memory 29 of the circuit of FIG. 4.

 The memory 56 or the memory 29 advantageously has a capacity of 128 kbytes corresponding to 4096 records.

 Depending on the number of recordable recordings, a compromise is made between the sampling frequencies of the analog (5ms) and digital inputs (îms? And the total recorded recording time (10s before and 5s after the appearance of the fault). These parameters are programmable.

 We can consider making devices with different characteristics. You just have to modify the software.

 Fig. 6 gives by way of example the internal architecture of the device shown diagrammatically in FIG. 3.

The inputs 15 are grouped together on an analog input interface card 60 produced by the
Applicant using operational amplifiers adapting independence and tension.

 An analog card 61 of the ADAC 735 type with sixteen inputs and two outputs is connected to this card.

 This card is in turn connected to an analog output multiplexing interface card 62 connected to a logic / analog interface card 63 intended to possibly replace the reproduction of an analog value by a logic value chosen from the thirty two logic outputs.

 To the card 62 is also connected a control interface card 64 comprising in particular the push button 34 (FIG. 3).

The circuit of FIG. 6 further includes an input / output type extension card 65
SBC 519 connected to the control interface card 64 and to two logic input / output interface cards 66, 67 each having sixteen inputs connected to type 68 and 69 galvanic isolation cards
PB16A, sixteen logic selection inputs and sixteen display outputs.

 The two cards 66, 67 are connected to a microprocessor card 70 of the SBC 80/24 type corresponding to the circuit 28 of FIG. 4 and a bubble memory card 71 corresponding to the memory 29 of the circuit of FIG. 3.

 The cards 61, 65 and 70 are connected by a bus 72 with multiple conductors.

The card 70 is for example a microprocessor card based on 8085 with 48 parallel inputs / outputs
3 programmable time bases
8 levels of interruption
4 kbytes of RAM
16 kbytes of ROM
The apparatus which has just been described makes it possible, after having identified an operating anomaly in a set of relays controlling the operations of a machine, to establish on demand and on site a logic connected to remarkable points in the area of the relays in which the failure manifests itself and likely to generate a fault signal, the processing of which by the device makes it possible to precisely locate the relay which causes the anomaly.

Claims (14)

 1. Method for determining disturbances in the course of an operating sequence of an industrial process controlled by a set of relays, characterized in that it consists in establishing the remarkable points of the sequence to be checked in which the disturbance, to define a combinational signal of the various inputs, intended to change state at the time of the disturbance, to sample, to record the signals appearing at the remarkable points until the change of state of the combinative signal and to exploit in time delayed recordings to determine the remarkable entry that is causing the disturbance.  2. Method according to claim 1, characterized in that the combinatorial signal of the various inputs is established by carrying out on demand a logic whose inputs are the remarkable points of said sequence, said logic being intended to establish a logic equation corresponding to fault sought.  3. Device for determining disturbances intended for the implementation of the method according to one of claims 1 and 2, characterized in that it comprises inputs intended to be connected to the remarkable points of the sequence to be checked, means ( 45) for combining the signals of said inputs into a combinational signal intended to change state at the time of the disturbance, means (13) for sampling and recording the signals appearing at said inputs until the signal state changes combinatorics of disturbance and means (14) for delayed reading of the records to determine the remarkable input which is causing the disturbance.  4. Device according to claim 3, characterized in that said means for combining the signals of said inputs into a combinational signal are constituted by a logic circuit (45,46.47) established on demand, intended to materialize a logic equation corresponding to the conditions d appearance of the malfunction sought.  5. Device according to one of claims 3 and 4, characterized in that said recording means (13) comprise a programmable circuit (22; 55) for sampling the signals applied to the inputs, associated with a device (28; 54) of detection by comparison of the changes occurring in the input signals and of management of the time intervals and a memory (29; 56) for storing data relating to the successive states of the sampled input signals.  6. Device according to one of claims 3 to 5, characterized in that the sampling device (22; 55) is a programmable time base circuit.  7. Device according to one of claims 3 to 6, characterized in that the device for detecting changes and managing time intervals is constituted by a microprocessor controlling the sampling device (22; 55) and said memory ( 29; 56).  8. Device according to one of claims 3 to 7, characterized in that it further comprises a device (30) timed recording stop intended to cause the interruption of a recording on receipt of a fault signal from said logic circuit (45,46,47).  9. Device according to one of claims 3 to 8, characterized in that the reading device (14) comprises an addressing circuit (32) controlled by a time-based circuit (33) and intended to cause the reading in said memory (29) data relating to a situation of the remarkable points of a monitored installation, means (38, 39) for controlling the addressing of a preceding time interval and of a time interval following the time interval corresponding to said situation, being associated with said addressing circuit (32).  10. Device according to claim 9, characterized in that the reading device comprises means (35,36,37) for graphic recording control associated with said time base (33).  11. Device according to any one of claims 3 to 10, characterized in that it comprises means (2X, 24a) for displaying the state of the inputs connected to said remarkable points to be monitored as well as means (27,27a ) display of the entries recorded at the time of the fault.  12. Device according to any one of claims 3 to 11, characterized in that said recording means (13) and the reading means (14) comprise a part (22,23,24,27,28,29, 32, 33, 35) for processing digital input signals and a part (17,18,20,22,28,29,40,41) for processing analog input signals.  13. Device according to claim 12, characterized in that the part of the recording device (14) intended to process the analog signals comprises an analog-digital converter (17) controlled by the programmable sampling device (22) and connected to device 128) for detecting change and managing time intervals.  14. Device according to one of claims 12 and 13, characterized in that the part of the reading device (14) intended to process the analog signals comprises a digital analog converter and multiplexing (40).