EP0936066B1 - Control device for a printing press - Google Patents

Abstract

The controller has several units, e.g. printing mechanisms and lacquering devices, associated with at least one station (2.1-2.3) with a computer. The individual stations are connected together by a first bus (6) carrying commands. The printer has an angle sensor (4) whose signals are passed to the stations over a second bus (7). The absolute angle sensor feeds an evaluation unit (5) that extracts absolute angle values from the sensor's incremental signals. Absolute angle values are conveyed by the first bus with the machine idle. With the machine active, the values passed over the first bus with the machine idle are processed to give current actual angle setting values using the incremental signals from the second bus.

Description

The invention relates to a control for a printing press according to the preamble of claim 1.

A large number of processes are dependent on sheetfed offset printing machines the angular position of the cylinders / rollers. These are examples Pressure switching, i.e. the on / off the blanket cylinder to the Plate cylinder or the impression cylinder. More depending on the angular position switching processes are in particular the format length of the substrate aligned switching of dryer devices, powder devices and sensors controlling the sheet travel. Sheetfed offset presses from widespread type usually have a central control in the form of a PLC or PC board control on. This control is on one with an angle encoder single-speed shaft in connection, so that the angular position values this Angle encoder within the control (a computer) with stored target angular position values compared for switching operations to be triggered accordingly can be. Such central controls have the disadvantage that this according to the equipment of the machine (number of printing units, coating and other inline finishing facilities) must be designed.

A control for a printing press is known from DE 195 20 919 A1 which the printing press several units such as feeder, printing units, Painting equipment, boom and the like. The individual units are assigned stations designed as computers, which via a particular connected to each other on a message-based protocol are. An absolute or incremental angle encoder is arranged on one of the units (single-revolving shaft), whose angular position values over a separate bus system (angular bus) to the individual stations. On detected in a unit via sensors arranged in the respective station Event is communicated to the other units via the first bus system, whereupon the functions to be triggered according to the determined event the station computers in the other units depending on the angular position signals triggered on the angle bus. This is done in the respective Station a comparison of the angular position signals present on the angular bus (Actual angular position) with target angular position values stored in the respective station.

In the above-mentioned document, incremental or. Called absolute angle encoder. Accordingly, the angle bus is for transmission the angular position values as one of the incremental or absolute angular position values transmitting bus system. Becomes an absolute angle encoder and a parallel bus system for transferring the absolute angular position values used, such a training expensive because of the associated Wiring costs the bus system considerably. Also very much The use of a fast serial bus system is cost-intensive Transmission of the absolute angular position signals of an absolute angle encoder With a high resolution rate of the absolute angle encoder, however, do not have to only the bus system but also the interfaces in individual units Reading the angular position values should be designed to be correspondingly powerful.

The use of an incremental encoder as an angle encoder has the disadvantage that that an absolute angular position information in the form of a zero pulse only at Run of the machine can be obtained. Accordingly, after the start of the Machine does not depend on the angular position until the first receipt of a zero pulse switching operations to be triggered. On the other hand, it is advantageous the usability of an incremental bus for transmitting the signals of the incremental encoder because of the small number of lines and the lower Isolation effort.

The object of the present invention is therefore a control according to the Develop the preamble of claim 1 such that, while avoiding the Disadvantages mentioned above by reducing the construction effort an inexpensive design of a bus system transmitting angular position values is obtained.

This object is achieved by the characterizing features of claim 1. Further developments of the invention result from the subclaims.

According to the invention it is provided that in one of the units of the printing press an absolute angle encoder is provided, the absolute angle position signals converted into incremental signals by a downstream evaluation electronics are, these incremental signals during machine operation over the as Incremental bus trained angle bus to the individual stations (computers) of the Units are supplied. The evaluation electronics of the absolute angle encoder stands additionally with which the individual stations for the transmission of Switching commands connecting bus system in connection, so that at Machine standstill absolute angular position values at the other stations are transferable. This ensures that even when the machine is at a standstill each of the stations (computers) has information about the current one Angular position the machine is currently.

In the individual stations there are evaluation devices in the form of suitable programs stored or appropriate hardware modules (switchgear) installed, to the absolute values transmitted via the signal bus when the machine is at a standstill Angular position values in connection with the incremental signals when the machine is running permanently the necessary angular position signals in the form of actual angular positions to build. This is done according to a simple embodiment of the Invention in that the incremental signals of the transmitted the incremental signals Angular bus to that at the last machine shutdown over the Absolute angular position value transmitted in the signal bus can be added.

Due to the actual angular position values that can be generated in the individual stations are then to be carried out in the respective units depending on the angular position Switching functions can be triggered. For example, by a sensor in the unit representing the first printing unit of the machine a missing sheet of the system, a corresponding command "Missing sheet system" is via the one based in particular on a message-oriented protocol Bus system forwarded to the other stations. In each of the individual Units (individual printing units) is then the according to the sheet run Blanket cylinder at the intended angular position of the impression cylinder and then turned off from the blanket cylinder. This will be done in the individual Units (printing units) in an evaluation group the currently available ones Actual angular position values - generated from those transmitted when the machine is at a standstill absolute angular position values together with the total angular increments - With the intended for the switching operation to be undertaken Target angular position values compared and if there is a match, the respective Switching process triggered. This is shown here using the example of switching the pressure off In the event of a faulty sheet, evaluate and process the system as described the angular position signals in the individual units are sent accordingly other events in the same way.

According to a preferred development of the invention it is provided that each Station, for example, arranged in the evaluation group and an offset angle value containing memory, the content of which is permanent from the initial value of the counter of the evaluation group providing the current actual angle value is subtracted. This offset angle value is for the individual Stations of the units chosen in such a way that to be executed on a specific command Switching operations in each station with a uniform target angular position value can be triggered.

For the "pressure-down" command, this means, for example, that the corresponding target angular position value is uniformly at X _{pressure-down} degrees. Since the offset angle value in the individual stations of the printing units in this embodiment of the invention is chosen in accordance with the path of the printing material in angular degrees (angular distance or angle difference) between two printing units, the output of the evaluation group (actual angular position value generated by the incremental signals) is minus the offset angle value of the respective printing station is an individual actual angular position value for this station. If the distance between two printing units is DW _distance degrees, the offset value in the first printing unit Off _DW1 : = 0 degrees, for example. In the case of a sheet-fed printing press with units of the same type _strung together, this then means that the offset value in the second, third, ... nth printing _units Off _DW2 = 1 · DW _distance , Off _DW3 = 2 DW _distance , ..., Off _DWn = (n - 1) DW _distance . As a result, the individual printing station each receive an individual actual angular _{position value} X _{DW1, ist} , X _{DW2, ist} , X _{DW3, ist} , ..., X _{DWn, ist} . These actual angular position values decrease with an increasing number of printing units, so that the switching times are generated in accordance with the sheet travel in the individual printing units with a uniform target value X _print-down for the print-off setting.

The advantage of the embodiment of the invention described above is that that in the stations (computers) the same units for each to be executed Commands must always save the same target angular position values. The only difference then is the offset angle values through which the modification the actual angle values take place.

With a sheet-fed printing machine that can be converted from perfecting to perfecting can, in addition to a first angle encoder (before the turn), a second one Angle encoder (after the turn) should be provided. The signals from the angle encoder, attached to the part to be rotated when moving the machine are then used for format-dependent positioning. When the machine is running can use the signals from the two angle sensors for monitoring the coupling device the turn can be evaluated in a suitable manner.

Furthermore, an exemplary embodiment of the invention is explained on the basis of the drawing.

Fig. 1

der erfindungsgemäße Winkelbus nebst dem Absolutwinkelgeber und die einzelnen Stationen, und

Fig. 2

die Winkelauswertung in einer der Stationen.

It shows:

Fig. 1

the angle bus according to the invention together with the absolute angle encoder and the individual stations, and

Fig. 2

the angle evaluation in one of the stations.

According to FIG. 1, a printing machine, not shown, has a plurality of units 1.1, 1.2, 1.3 in the form of an investor, one or more printing units, painting equipment as well as a boom. The individual units are 1.1- 1.3 each assigned to stations 2.1 - 2.3 comprising at least one computer, by which the switching operations to be carried out in the respective unit 1.1 - 1.3 as well as monitoring the sheet travel (sensors - not shown), etc. become.

An angular encoder is located on a single-speed shaft of the printing press, not shown 4 in the form of an absolute angle sensor, to which an electronic evaluation unit 5 is connected downstream. According to the invention it can be provided that the evaluation electronics 5 integrated in one of the stations 2.1 - 2.3 of the units 1.1 - 1.3 is.

The individual stations 2.1 - 2.3 of the units 1.1 - 1.3 are in particular by one based on a message-oriented protocol (e.g. CAN bus) Bus 6 for exchanging signals in the sense of commands or messages connected with each other. For example, within the stations 2.1 appropriate sensors detect an event (e.g. "missed sheet system"), whereupon via the first bus 6 signals representing the event (Message) to be forwarded to the other stations 2.2, 2.3.

The individual stations 2.1 - 2.3 are through a second bus 7 as an angle bus connected with each other. This second bus 7 is designed as an incremental bus, i.e. over the lines of this bus 7 are corresponding to the rotation of the Machine and the resolution of the angle encoder 4 incremental signals. The second bus 7 is directly connected to the output of the evaluation electronics 5 of the angle encoder 4 connected. To generate the incremental signals for this Signals transmitting bus 7 is preferably the bit of the angle encoder 4 evaluated at the highest resolution and provided as incremental signals.

The evaluation electronics 5 of the angle encoder designed as an absolute angle encoder 4 stands over a corresponding interface with which the signal exchange between the individual stations 2.1 - 2.3 serving first bus 6 in connection. It is provided that when the machine comes to a standstill via the bus 6 each current and delivered by the angle encoder 4 angle value to the individual Stations 2.1 - 2.3 is sent.

The individual stations 2.1-2.3 have suitable hardware components (Interfaces, bus couplers and the like) as well as corresponding program routines realized evaluation groups 3.1 - 3.3, each with one input with the Signal exchange and the transmission of the absolute angular position values (at Machine standstill) bus 6 and the transmission of the incremental signals serve bus 7 are connected.

2 shows the basic components of an evaluation group 3.1 in detail. At this Embodiment variants of the invention are those via the bus 6 when the machine is at a standstill transferable absolute values of the angle encoder 4 a first input a loadable counter 8 fed to the evaluation group 3.1. This loadable counter 8 is via a second input with that of the transmission of the incremental signals serving second bus 7 connected such that the machine running on this Counter 8 applied signals of bus 7 increase the absolute value in counter 8 and this provides the corresponding value at the output as the actual angle value.

The output of the counter 8 containing the current actual angle value becomes one Totalizer 9 supplied, on the other hand with that contained in a memory 10 Offset angle value is related. Through the totalizer 9 because of the sign of the sizes to be linked, shown in FIG Subtraction of the offset angle value from that provided by the counter 8 current actual angle value. Thus station 2.1 stands around the offset angle value corrected angle value is available, which is indicated by a connection Computer system of the station 2.1 is supplied. With these for the respective Offset angle value corrected actual angular position values are then compared with the target angular position values stored in station 2.1, in order to over the events / commands transmitted in bus 6 in unit 1.1 Carry out switching operations or actions.

Reference list

1.1 - 1.3

unit

2.1 - 2.3

Station (computer)

3.1 - 3.3

Evaluation group (station 2.1 - 2.3)

4th

Angle encoder (absolute angle encoder)

5

Evaluation unit (angle encoder 4)

6

Bus (signal exchange between stations 2.1 - 2.3)

7

Bus (transmission of incremental signals)

8th

Counter (evaluation group 3.1-3.3)

9

Totalizer (evaluation group 3.1 - 3.3)

10th

Memory (evaluation group 3.1 - 3.3; offset angle value)

Claims (4)

1. Control device for a printing press, particularly an offset sheet printing press, wherein the printing press has several units such as feeder, printing units, varnishing devices, delivery and the like, to which units are fitted in each case at least one station having a computer, the individual stations are connected with one another via a first bus for the transfer of commands and the press has an angle sensor, the signals of which can be fed via a second bus to the individual stations, characterised in that the angle sensor (4) is constructed as an absolute angle sensor with a downstream connected evaluation unit (5), from which incremental signals which can be generated by the angle sensor (4) as well as absolute angle values can be extracted, that, via the first bus (6) with the press stationary, the absolute angle values of the evaluation unit (5) of the angle sensor (4) can be transferred, that the second bus (7) is constructed as a bus transferring the incremental signals of the evaluation unit (5), and that, with the press running in each of the stations (2.1 - 2.3), the absolute angle values of the angle sensor (4) transferred via the first bus (6) with the press stationary can be processed in combination with the incremental signals of the second bus (7) to current actual angle position values.
2. Control device according to Claim 1, characterised in that via the evaluation unit (5) incremental signals can be generated from the bit of the angle sensor (4) with the highest resolution, and can be fed to the second bus (7).
3. Control device according to Claim 1 or 2, characterised in that the stations (2.1 - 2.3) in each case have an evaluation module (3.1 - 3.3) with a loadable counter (8) which is connected with a first input with the first bus (6) for transfer of absolute values sent with the press stationary and with a second input with the second bus (7) for transfer of the incremental signals, and that, by the counter (8) with the press running, the absolute angle value corresponding to the incremental signals can be summed up and the value of the counter (8) is fed at one output as a current actual angle value to the computer systems of the stations (2.1 - 2.3).
4. Control device according to Claim 3, characterised in that the evaluation modules (3.1 - 3.3) have in each case a store (10) connected via a summer (9), the output of the counter (8) which contains an offset angle value, that, via the summer (9), the offset angle value is continuously subtracted from the angle value present in the output of the counter (8) and that the difference value present at the output of the summer (9) can be fed to the computer systems of the stations (2.1 - 2.3) as a current actual angle value.

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