EP0187247A2 - Method and device for controlling the braking of a drive motor in a printing press - Google Patents

Abstract

In a method and a device for brake control of a motion-monitored and controlled drive motor (1) in a printing press, a control logic (5) is provided, which on the input side has a device for generating a motion signal (3) and a motion-determining command input (11) and on the output side a power actuator (4) designed as a converter is connected to the drive motor (1) and associated motor brake (2). The control logic (5) generates signals for motor and brake control, with the drive motor (1) briefly applying a small movement setpoint αVor, nVor or SVor as a test specification before each start with the motor brake (2) still closed, and then its actual movement value αactual , n Actual or actual is determined. If αIs, is or is> | 0 | the braking torque is insufficient and an error message is generated and the drive motor (1) is switched off. If αIst, nIst or SIst = 0, the motor brake (2) is released, the test specification αVor, nVor or SVor is maintained and the actual motion value αIst, nIst or SIst of the drive motor (1) is checked repeatedly. If αIst, nIst or SIst = 0, the motor brake (2) has not released properly, whereupon an error signal is generated and the drive motor (1) is stopped. With αist, nist or Sist> | 0 | the functional check of the motor brake (2) is completed and the drive motor (1) is raised to the desired movement αSoll, nSoll or SSoll.

Description

The invention relates to a method and a device for brake control of a motion-monitored and -controlled drive motor in a printing press.

As a result of safety requirements, it is known to use machines with rotary motion sequences, such as Offset printing machines whose drives are equipped with a switchable motor brake. On the one hand, this serves as a parking brake to guarantee the operator protection against unintentional starting of the machine drive at a standstill and, on the other hand, as an emergency brake, in order to decelerate and brake the machine drive as quickly as possible due to an emergency situation.

Such engine brakes generally consist of discs provided with brake pads, which are pressed against one another in the de-energized state by spring forces, the required braking force being caused by the resulting frictional engagement between the two brake discs. By applying a voltage, the brake disks are moved apart in the axial direction against the force of compression springs and thus their braking force is released.

To check the function of such motor brakes, limit switches have been provided which sense the position of at least one of the movable brake discs. For example, the drive motor is prevented from starting if the brake disks do not move apart after the aforementioned voltage has been applied and as a result do not contact the limit switch or switches so that they cannot report that the motor brake has been released. The disadvantage of such a brake control, however, is that only the absolute positions of the brake discs are monitored with respect to one another and no statement can be made about the function of the motor brake or the actual braking force applied by it, since the limit switch or switches are not in the Are able to determine a thinning of the brake pads due to wear and tear due to use or another defect, such as contamination by oil. Apart from this, an incorrect setting of the limit switch (s) or an adjustment of their switching points after a long period of operation cannot be completely ruled out, which means that operating uncertainties of the drive have to be accepted.

Based on this prior art, the invention has for its object to develop a method and a device for existing drive motors in printing presses - in particular for the printing press drive itself - which can be retrofitted independently of wear and tear with minimal effort, with little manufacturing effort Allow time at all times to ensure an absolutely safe function check of the engine brake.

This object is achieved - starting from the method according to the preamble of claim 1 - according to the invention in that before and when the drive motor starts, a check is made with an open and closed motor brake for an impermissible and permissible movement, depending on the result of which drive-influencing control steps and / or error signals to be triggered. In terms of the device, the solution of the problem according to claim 6 is that a control logic is provided, the input side with a motion signal generator and a motion-correcting command input and the output side. is coupled via a power element to the drive motor and the motor brake assigned to the drive motor.

This method, together with the associated device for carrying it out, contributes significantly to increasing the loading operating safety of the printing press, since the brake system is continuously monitored when the operator is completely relieved and is automatically checked anew each time the machine is started. It is advantageous that, in addition to wear-related wear and tear of the brake pads, mechanical and electrical faults that impair the function of the motor brake can also be determined, which also helps to protect and avoid overload conditions of the drive motor - for example when the motor brake is not or only partially open - and to avoid increased ones Signs of wear on the brake pads can contribute.

In an expedient continuation of the concept of the invention, at least one movement setpoint jump is predefined for the drive motor for the movement check and at the same time the drive torque of the drive motor is reduced as required, after which at least one movement check of the drive motor is carried out.

• 1. Auslösung eines Motor-Startsignales;
• 2. Erzeugung eines Bewegungs-Sollwertsprunges in Form eines, einer kleinen Motor-Bewegungsgröße proportionalen Bewegungssignales als Prüfvorgabe;
• 3. Bewegungsüberprüfung des Antriebsmotors;
• 4. Bei Vorliegen einer unzulässigen Motorbewegung Erzeugung einer Fehlermeldung;
• 5. Rücknahme der Prüfvorgabe und Auslösung eines Motor-Stoppsignals;
• 6. Nach Feststellung, daß keine unzulässige Motorbewegung vorliegt, lüften der Motorbremse;
• 7. Aufrechterhaltung des Bewegungs-Sollwertsprunges als Prüfvorgabe;
• 8. Erneute Bewegungsüberprüfung des Antriebsmotors;
• 9. Nach Feststellung, daß keine zulässige Motorbewegung vorliegt, Erzeugung einer Fehlermeldung;
• 10. Rücknahme der Prüfvorgabe und Auslösung eines Motor-Stoppsignals; .
• 11. Bei Vorliegen einer zulässigen Motorbewegung Sollwertvorgabe entsprechend der gewünschten Bewegungsgröße des Antriebsmotors.

An advantageous further development of the inventive concept consists of the following process steps:

• 1. triggering an engine start signal;
• 2. Generation of a movement setpoint step in the form of a movement signal proportional to a small motor movement quantity as a test specification;
• 3. motion check of the drive motor;
• 4. If there is an impermissible motor movement, an error message is generated;
• 5. withdrawal of the test specification and triggering of an engine stop signal;
• 6. After determining that there is no impermissible motor movement, release the motor brake;
• 7. Maintenance of the movement setpoint jump as a test specification;
• 8. Recheck the drive motor movement;
• 9. After determining that there is no permissible motor movement, an error message is generated;
• 10. withdrawal of the test specification and triggering of an engine stop signal; .
• 11. If there is a permissible motor movement, the setpoint is set according to the desired movement size of the drive motor.

In this simple manner, it can easily be determined in a first test procedure before starting the drive motor whether the braking torque provided by the motor brake is still sufficient and in a second test process whether the motor brake actually opens for starting the drive motor.

In order to rule out overloading of the drive motor, in a further embodiment of the device for brake control according to the invention, the control logic is equipped with a switching logic which can be influenced via the command input, which has both a brake control connected upstream of the motor brake and a device for limiting the motor drive torque as well as a device for the movement setpoint -Preparation for the power actuator is coupled, the latter also being connected to a device connected downstream of the motion signal generator for motion signal adaptation.

This device can be installed imperceptibly and subsequently in every start-up routine of a printing press drive. In the case of printing machines with a start-up warning, the check of the applied braking torque of the drive described above is preferably placed in the start-up warning time, while the second check of the brake opening actually carried out is carried out immediately after the first check has been carried out when the drive motor starts. Further features and details essential to the invention as well as the advantages resulting therefrom result from patent claims 4 and 5 as well as from 8 to 10 and from the following description of an exemplary embodiment with reference to the drawings.

• Fig. 1 Ein schematisches Blockschaltbild einer Einrichtung zur Bremsenkontrolle nach der Erfindung,
• Fig.2 einen Schaltungsauszug aus Fig. 1 mit schematischer Darstellung des Logikteils als Blockschaltbild,
• Fig. 3 ein Flußdiagramm mit Verfahrensschritten zur Bremsenkontrolle,
• Fig. 4-9 Kurvendiagramme zur Bremsenkontrolle vor Anlauf des Antriebsmotors mit angedeutetem Fehlerfall,
• Fig. 10-15 Kurvendiagramme zur Bremsenkontrolle nach Anlauf des Antriebsmotors mit angedeutetem Fehlerfall,
• Fig.16-21 Kurvendiagramme zur Bremsenkontrolle ohne Fehlerfall.

It shows:

• 1 is a schematic block diagram of a device for brake control according to the invention,
• 2 shows a circuit extract from FIG. 1 with a schematic representation of the logic part as a block diagram,
• 3 is a flowchart with method steps for brake control,
• 4-9 curve diagrams for brake control before start-up of the drive motor with an indicated fault,
• Fig. 10-15 curve diagrams for brake control after start-up of the drive motor with indicated failure,
• Fig. 16-21 Curve diagrams for brake control without an error.

In the exemplary embodiment described below, the speed "n" of the drive motor is selected as the movement variable. In principle, however, the functional sequence would be the same if instead the path, i.e. the angle adjustment "α" or, if a linear motor was used, the path "S" of a linear movement would be used as the movement quantity.

According to -Fig. 1 as the drive motor 1 is a speed change barer motor is provided, which can be designed for example as a DC motor. The drive motor 1 is provided with a motor brake 2; its movement, ie the speed, is controlled by means of a movement signal transmitter 3 (in the exemplary embodiment: tachometer generator). However, the speed control can also be carried out via the control variable, in the case of the direct current motor the armature voltage feedback, which is indicated by the reference number 25 in FIGS.

A power actuator 4, which is designed as a converter, is connected upstream of the drive motor 1, it being possible to use a frequency converter or other power-equivalent power actuators with corresponding drive motors instead of the converter. The power actuator 4 is controlled by a logic part 5, which consists of a device for brake control 6, a switching logic 7, a device for movement setpoint processing 8 (in the exemplary embodiment: speed setpoint processing), a device for movement signal adaptation (9) (in the exemplary embodiment : Device for. Tacho signal adaptation) and a device for limiting the motor drive torque 10 (in the exemplary embodiment: device for influencing the motor torque). In the present exemplary embodiment, the motor torque is influenced by changing the current limit of the converter 4. The individual elements 6 to 10 of the logic part 5 are linked to one another for the purpose of generating signals for motor and brake control. The switching logic 7 and the device for the speed setpoint conditioning 8 can - as indicated by dash-dotted lines in FIG. 2 - be combined in an electronic component.

As shown in FIG. 2, the brake control 6 is connected to the engine brake 2 and supplies its control signals. The switching logic 7 is simplified with one shown command input 11 coupled. Buttons, switches or potentiometers or electronic control devices (not shown and described in more detail) are provided as control elements of the command input 11, with which the operator exerts influence on the machine speed and command inputs such as "commissioning", "faster", "slower", "forward""," Backward "," Halt "," Not-Stop "and others.

In the switching logic 7, these command inputs are linked according to their priorities, locked and processed into signals which are fed to both the brake control 6 and the device for the speed setpoint processing 8. The device for the speed setpoint processing 8 derives the speed setpoint from these signals in conjunction with the respective actual speed value of the drive motor 1 which is reported to the device for the speedometer signal adjustment 9 and converted there by means of the tachogenerator 3 (or alternatively the armature voltage feedback message 25). This is predefined for the converter 4, which, depending on the size of the speed setpoint, outputs an output voltage or an output current of a corresponding magnitude for controlling the downstream drive motor 1 (FIG. 2).

The mode of operation of the device described above and the process sequence for brake control are described below with reference to FIGS. 2 to 20.

The method steps of the first and second checking of the motor brake 2 and their chronological order are illustrated in the network plan in FIG. 3, the time-related diagrams in FIGS. 4 to 15 being assigned to the individual method steps.

The functional descriptions only refer to the Speed feedback by means of the tachometer generator 3 referred. In principle, the functional sequence is the same if the armature voltage feedback 25 mentioned at the beginning is selected instead of a tachometer generator 3

By pressing the "start-up" button, an engine start signal 17 is triggered at time 16 (FIG. 4). In this process step is shown in Figure 18 by the means for speed setpoint conditioning 8 of the logic portion 5 the converter 4 automatically for a short time period 19 a speed reference value n _in the form of a small voltage signal (Fig. 5) is given, 4 is a sufficiently high depending on which of the power converter Supply voltage or a supply current for controlling the drive motor 1 is generated. The supply voltage or the supply current which occurs on the drive motor 1 serves as a test specification and is dimensioned by the device for limiting the motor torque 10 such that it can rotate safely when the motor brake is open or when the motor brake 2 is not sufficiently effective.

However, since at this point in time the switching logic 7 would not yet pass on the "release brake" signal to the brake control 6 and from there to the motor brake 2, the drive motor 1 must also not yet rotate in the normal case, ie with the motor brake 2 intact. At. On the other hand, the reduced locking force of the motor brake 2, for example as a result of natural wear and tear, causes the drive motor 1 to start up according to FIG. 7 at a speed n _actual and takes up a current determined by the torques - that is, current limitation below a current limit value 26, which is shown in FIG is

After the time period 19 (FIG. 5), this function is checked in accordance with method step 20, in that the speed sensor 3 detects the engine speed n _actual and via the device for speedometer signal adjustment 9 of the device for speed setpoint conditioning 8 reports in which the actual speed control takes place. If it is determined here that the engine speed n _actual exceeds the value 0, the engine brake 2 remains unventilated, ie closed, according to FIG. 8, and the speed test specification n _before is withdrawn (method step 21), by means of the switching logic 7, by setting a further speed setpoint value. Output to the converter 4 is prevented.

An engine stop signal 22 is triggered, as a result of which the _actual speed _value n _actual shown in FIG. 7 _drops to zero. The drive motor 1 is braked in a known manner via the motor current (FIG. 6). At the same time, an error message 23 is generated (FIG. 9), which alerts the operating personnel of the printing press acoustically and / or optically to a faulty brake function at the time 24 of the first speed check.

In the second function check of the motor brake 2, the method steps 17-20 are the same until the first check of the actual speed value n _{actual of} the drive motor 1. Accordingly, the curve diagrams of FIGS. 4 and 5 essentially correspond to those of FIGS. 10 and 11, with the difference that after the time period 19 of the speed setpoint test specification n before, a further time period 27 is specified for the first function check of the engine brake 2 for its second check. This continues until the point in time identified by reference number 28 at which a second speed check 33 of the drive motor 1 takes place. The withdrawal of the speed setpoint specification n _before is identified in FIG. 11 by reference number 36.

In the first speed check by tachometer generator 3 in accordance with first method step 20 of the network diagram in FIG. _3, no actual speed value of drive motor 1 - consequently n _is = 0 - determined (Fig. 13), then the engine brake 2 still has a sufficiently high braking torque, which is reliable evidence of a sufficient locking force. Triggered by the switching logic 7, the means for speed setpoint conditioning 8 will now be further speed setpoint output and the maintenance of the inspection specification n _before permitted and also achieved through the means for braking controller 6 in the next process step 32, the time 24, the engine brake 2 (Fig. 14). At the same time, the current limit value 26 is set to the value of the maximum drive current. 12 shows the basic course of the current consumption of the drive motor 1 with effective current limitation.

Now the second speed check 33 of the drive motor 1 by means of the tachometer generator 3 and the device for the tachometer signal adaptation 9 is used, with which it is to be determined whether the motor brake 2 has actually opened and the drive motor 1 after the command “release brakes” turns. If it is found during this second speed check 33 that the drive motor 1 is not rotating and consequently no actual speed value n _actual > | 0 | generated, in an equivalent manner to the process step 21, n to the previously elapsed first brake control at the time 28 according to the rotation speed target value setting withdrawn _before in that the switching logic 7 is a further target value output from the means for speed setpoint conditioning 8 to the power actuator 4 is prevented. In addition, the engine stop signal 22 is triggered and the error message 23 (FIG. 15) is generated. Since the drive motor 1 does not first have to be braked via its motor current, its value drops to 0 (FIG. 12). In addition, the "release brakes" command is withdrawn (FIG. 14).

After the triggering of the error signal 23, a check of the brake status by the operating or Maintenance personnel take place, depending on the result of which the engine start 17 is initiated repeatedly.

The curve diagrams in FIGS. 16-21 illustrate the sequence of a proper brake check without an error occurring.

_F ig. 16 shows the engine start signal 17 from the triggering time 16, through the first and second speed checks 20 and 33 and an additional machine running time 35. The curve in FIG. 17 illustrates that after the second brake control and the intact engine brake 2 have been completed, the speed setpoint test specification n _pre specified as a voltage signal is increased to the desired operating speed _setpoint n _set (method step 36) with which the printing press continues to be operated should. The course of the motor current is shown schematically in FIG. The dependence of its size on the torque requirement is well known and therefore need not be described in more detail.

Only after both speed checks 20 and 33 have passed satisfactorily, ie n _{actual has} the value 101 in the first speed check 20, and n _is a value> | 0 | in the second speed check ₃₃ 19, the drive is released and, according to the curve in FIG. 19, the actual speed value nact is ramped up and adjusted to the operating speed _setpoint n _target up to a constant nominal speed. 20 shows the course of the brake signal with the signal jump caused by the command "release brake" at time 24. According to the diagram in FIG. 21, as already described above - no error signal triggered during the proper control process (FIGS. 16-20).

It goes without saying that the invention is not limited to the embodiment set out in the description and shown in the figures, but instead numerous structural modifications, such as the use of equivalent both electromechanical and electronic components available on the market, within the scope of Invention lie.

REFERENCE NUMBER LIST

• 1 drive motor
• 2 engine brake
• 3 motion signal generator (tachometer generator)
• 4 power actuator (converter)
• 5 control logic
• 6 Device for brake control
• 7 switching logic
• 8 Movement setpoint processing device (speed setpoint processing)
• 9 device for movement signal adaptation (tachometer signal adaptation)
• 10 device for limiting the motor drive torque (motor torque)
• 11 Command entry
• 12
• 13
• 14
• 15
• 16 time of command input "engine start"
• 17 Engine start signal
• ₁₈ Speed setpoint specification n _before [V]
• 19 Period of time for specifying the speed setpoint
• 20 first speed actual value check
• ₂₁ Withdrawal of the speed setpoint specification n _before
• 22 Engine stop signal
• 23 Error message
• 24 Time of the first speed check
• 25 armature voltage feedback
• 26 Current limit
• 27 period between l. and 2. brake control
• 28 Time of the second speed check
• 29
• 30th
• 32 Release the engine brake
• 33 second speed actual value check
• 34 Brake condition control
• 35 additional machine run times
• ₃₆ Increase the speed _setpoint test specification n _forward to n _set

Claims (10)

1. Method for brake control of a motion-monitored and -controlled drive motor in a printing press,
characterized,
that before and when the drive motor starts, a check is made with an open and closed motor brake for an impermissible and permissible movement, depending on the result of which drive-influencing control steps and / or error signals are triggered. 2. The method according to claim 1
characterized,
that the drive motor is given at least one movement setpoint jump for the movement check and at the same time the drive torque of the drive motor is reduced as required, after which at least one movement check of the drive motor is carried out. 3. The method according to claim 1 and / or 2, characterized by the following process steps: 1. triggering an engine start signal; 2. Generation of a movement setpoint step in the form of a signal proportional to a small motor movement quantity as a test specification; 3. motion check of the drive motor; 4. If there is an impermissible motor movement, an error message is generated; 5. withdrawal of the test specification and triggering of an engine stop signal; 6. After determining that there is no impermissible motor movement, release the motor brake; 7. Maintenance of the movement setpoint jump as a test specification; 8. Recheck the drive motor movement; 9. After determining that there is no permissible motor movement, an error message is generated; 10. withdrawal of the test specification and triggering of an engine stop signal; 11. If there is a permissible motor movement, the setpoint is set according to the desired movement size of the drive motor. 4. The method according to one or more of the preceding claims,
characterized,
that the movement of the drive motor is of a rotary or translative type, the rotation of the motor being checked via the angular adjustment “α” or the rotational speed “n” and that of the translative motor movement via the path “S” of the linear movement as a movement variable. 5. The method according to one or more of the preceding claims,
characterized,
that a DC motor is used as the drive motor, the armature voltage feedback being used as the movement variable. 6. Device for brake control of a motion-monitored and -controlled drive motor in a printing press, which is provided with a motor brake and to which a motion control device is assigned, with a motion signal.
characterized,
that a control logic (5) is provided, the input side with a motion signal generator (3) and one motion-determining command input (11) and on the output side is coupled via a power actuator (4) to the drive motor (1) and the motor brake (2) assigned to the drive motor (1). 7. Device according to claim 6, characterized in
that the control logic (5) is equipped with a switching logic (7) which can be influenced via the command input (11) and which has both a brake control (6) connected upstream of the motor brake (2) and a device for limiting the motor drive torque (10) as well as a device for motion setpoint conditioning (8) for the power actuator (4) is coupled, the latter also being connected to a device for motion signal adaptation (9) connected downstream of the motion signal transmitter (3). 8. Device according to claim 6 and / or 7,

characterized in that the switching logic (7) links the control commands entered via the command input (11) in a priority-related manner, interlocks them and signals therefrom both for the brake control (6) for controlling the motor brake (2) and for the device for preparing the movement setpoint (8 ) forms, which are linked to output signals generated by the device for movement signal adaptation (9) for the preparation of movement setpoints for the drive motor (1), and that with the output signals of the device for movement setpoint preparation (8) via the switching logic (7) the device for limiting the motor drive torque (10) can be controlled, by means of which the drive torque limitation of the power actuator (4) can be changed. 9. Device according to one or more of claims 6 to 8,
characterized,
that the power actuator (4) is designed as a converter with a variable current limit level. 10. Device according to one or more of the preceding claims 6 to 9,
characterized,
that the drive motor (1) is designed as a rotary motor or linear motor.

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