DE19806141A1 - Control 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 controller for a printing press according to the Oberbe handle 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, d. H. 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 printing 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 multiple units such as feeders, printing units Painting equipment, boom and the like. The individual units are assigned stations designed as computers, which via a particular  bus based on a message-oriented protocol they are. An absolute or incremental angle encoder is attached to one of the units ordered (single-revolving shaft), its angular position values over a separate bus system (angular bus) to the individual stations. A 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 angle position signals are triggered on the angle bus. This is done in the respective current station, a comparison of the angular positions on the angular bus signals (actual angular position) with target win saved in the respective station position values.

In the above-mentioned document, incremental or Called absolute angle encoder. Accordingly, the angle bus is over Plot the angular position values as an incremental or absolute angle bus system transmitting position values. Becomes an absolute angle encoder and a parallel bus to transfer the absolute angular position values system used, such a training expensive because of the ver tied wiring effort 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 In 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 formation of a bus transferring angular position values systems 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 Druckma seem an absolute angle encoder is provided, the absolute angle position signals from a downstream evaluation electronics in incremental signals are converted, 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 len angular position the machine is currently.

In the individual stations there are evaluation devices in the form of suitable pro gram stored or appropriate hardware modules (switchgear) instal lated to the absolute from the signal transmitted when the machine is at a standstill th angular position values in connection with the incremental signals at Maschi the necessary angular position signals in the form of the actual angle  to form positions. This is done according to a simple embodiment of the Invention in that the incremental signals of the incremental signals over carried angular bus to that at the last machine shutdown above the Absolute angular position value transmitted in the signal bus can be added.

Due to the actual angular position that can be generated in the individual stations then the values in the respective units are dependent 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 the system is determined, a corresponding command "Missing To "based on a message-oriented protocol in particular ring 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 from the counter pressure cylinder and then parked from the blanket cylinder. For this purpose, in the individual units (printing units) in an evaluation group that are currently available Actual angular position values - generated from when the machine is at a standstill absolute values of the angular position together with the total angle incre elements - with those provided for the respective switching operation Target angular position values compared and if the respective switching operation 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 the angular position signals in the individual units are given 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 win kelwert containing memory, the content of the permanently initial value of the counter providing the current actual angle value subgroup is subtracted. This offset angle value is for the individual Stations of the units chosen in such a way that based on a specific command  supplying switching processes in each station at a uniform target angle 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 can be} set to 0 degrees, for example. In the case of a sheet-fed printing press with units of the same type lined up, this means that the offset value in the second, third,. . . nth printing unit Off _DW2 = 1st DW _distance , Off _DW3 = 2nd DW _distance ,. . ., Off _DWn = (n-1) .DW _distance is. As a result, the individual printing unit stations each receive an individual actual angular _{position value} X _{DW1, ist} , ist, X _{DW2, ist0} , X _{DW3, ist,.} . ., X _{DWn, is} . These actual angular position values decrease with an increasing number of printing units, so that the switching times of the sheet travel are generated accordingly in the individual printing units with a uniform target value X _print-off 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 modifications actual angle values.

With a sheetfed size that can be changed from perfecting to perfecting In addition to a first angle encoder (before the turn), the machine can also have a second one Angle encoder (after the turn) should be provided. The signals of the Winkelge  bers, which is attached to the part to be rotated when moving the machine are then used for format-dependent positioning. For machines The signals from the two angle encoders can be used to monitor the coupling tion device of the turn can be evaluated in a suitable manner.

Furthermore, an embodiment of the invention is explained hand of drawing.

It shows:

Fig. 1, the angle bus according to the invention together with the absolute angle encoder and the individual stations, and

Fig. 2 shows the angle evaluation in one of the stations.

Referring to FIG. 1, a printing machine, not shown, a plurality of units 1.1, 1.2, 1.3 in the form of a feeder, one or more printing units, Lackiereinrich facilities as well as a boom on. The individual units 1.1-1.3 are each assigned at least one computer comprising stations 2.1-2.3 , by means of which the switching operations to be carried out in the respective unit 1.1-1.3 and the monitoring of sheet travel (sensors - not shown) etc. are carried out.

An angle encoder 4 in the form of an absolute angle encoder is attached to a single-speed shaft of the printing machine, not shown, to which evaluation electronics 5 are connected. According to the invention it can be provided that the evaluation electronics 5 is arranged in one of the stations 2.1-2.3 of the units 1.1-1.3 .

The individual stations 2.1-2.3 of the units 1.1-1.3 are connected to one another by a bus 6 based in particular on a message-oriented protocol (for example CAN bus) for exchanging signals in the sense of commands or messages. Thus, for example, an event can be detected within the stations 2.1 by appropriate sensors (for example “missed sheet system”), whereupon signals (message) representing the event are forwarded to the further stations 2.2 , 2.3 via the first bus 6 .

The individual stations 2.1-2.3 are connected to one another by a second bus 7 as an angle bus. This second bus 7 is designed as an incremental bus, ie 4 incremental signals are transmitted via the lines of this bus 7 in accordance with the rotation of the machine and the resolution of the angle encoder. The second bus 7 is connected directly to the output of the evaluation electronics 5 of the angle encoder 4 . In order to generate the incremental signals for the bus 7 transmitting these signals, the bit of the angle encoder 4 with the highest resolution is preferably evaluated and provided as incremental signals.

The evaluation electronics 5 of the Winkelge encoder 4, which is designed as an absolute angle encoder, is connected via a corresponding interface to the first bus 6, which serves to exchange signals between the individual stations 2.1-2.3 . It is provided that is sent when a machine stop via the bus 6 and the respective current delivered by the angle encoder 4 angle value to the individual stations 2.1-2.3.

The individual stations 2.1-2.3 have evaluation groups 3.1-3.3 implemented by means of suitable hardware components (interfaces, bus couplers and the like) and corresponding program routines , each of which has an input with the purpose of exchanging signals and transmitting the absolute angular position values (when the machine is at a standstill) Bus 6 and the transmission of the incremental signals serve bus 7 are connected.

Fig. 2 shows the basic components of an evaluation group 3.1 in detail. In this embodiment variant of the invention, the absolute values of the angle encoder 4 that can be transmitted via the bus 6 when the machine is at a standstill are fed to a first input of a loadable counter 8 of the evaluation group 3.1 . This loadable counter 8 is connected via a second input to the second bus 7 serving for the transmission of the incremental signals, in such a way that the signals of the bus 7 applied to this counter 8 when the machine is running increase the absolute value in the counter 8 and this increases the corresponding value at the output as Provides actual angle value.

The output of the counter 8 which contains the current actual angle value is fed to a summer 9 which, on the other hand, is connected to the offset angle value contained in a memory 10 . The summer 9 subtracts the offset angle value from the current actual angle value provided by the counter 8 because of the signs of the variables to be linked, which are shown in FIG. 2. Thus, the station 2.1 has an angle value corrected by the offset angle value, which is fed to the computer system of the station 2.1 via an indicated connection. These actual angular position values, corrected by the respective offset angular value, are then used to compare them with the nominal angular position values stored in station 2.1 , in order to carry out the necessary switching operations or actions in unit 1.1 when events / commands are transmitted via bus 6 .

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

4th

)

6

Bus (signal exchange between the 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

Storage (evaluation group

3.1-3.3

; Offset angle value)

Claims (4)

1. Control for a printing press, in particular sheetfed offset printing press, the printing press having a plurality of units such as feeders, printing units, coating devices, delivery arms and the like. The units are each assigned at least one station having a computer, the individual stations via a first bus Transmission of commands which are connected to one another and the printing press has an angle sensor, the signals of which can be fed to the individual stations via a second bus, characterized in that the angle sensor ( 4 ) is designed as an absolute angle sensor with a downstream evaluation unit ( 5 ), which incremental signals and absolute angle values that can be generated by the angle encoder ( 4 ) can be found that the absolute angle values of the evaluation unit ( 5 ) of the angle encoder ( 4 ) can be transmitted via the first bus ( 6 ) when the machine is at a standstill, that the second bus ( 7 ) as an the incremental signals the evaluation Unit ( 5 ) transmitted bus is formed, and that when the machine is running in each of the stations ( 2.1-2.3 ) the absolute angle values of the angle encoder ( 4 ) transmitted via the first bus ( 6 ) when the machine is at a standstill in conjunction with the incremental signals of the second bus ( 7 ) can be processed at current actual angular position values. 2. Control according to claim 1, characterized in that the evaluation unit ( 5 ) from the bit of the angle encoder ( 4 ) with the highest resolution incremental signals can be generated and fed to the second bus ( 7 ). 3. Control according to claim 1 or 2, characterized in that the stations ( 2.1-2.3 ) each have an evaluation group ( 3.1-3.3 ) with a loadable counter ( 8 ) with a first input to the first bus ( 6 ) Acceptance of the absolute angle values sent when the machine is at a standstill and is connected to a second input with the second bus ( 7 ) for the acceptance of the incremental signals, and that the absolute angle value corresponding to the incremental signals and the value of the counter can be summed up by the counter ( 8 ) when the machine is running ( 8 ) can be fed to the computer system of the stations ( 2.1-2.3 ) at an output as the current actual angle value. 4. Control according to claim 3, characterized in that the evaluation groups ( 3.1-3.3 ) each have a memory ( 10 ) linked via a summer ( 9 ) to the output of the counter ( 8 ), which contains an offset angle value that by the totalizer ( 9 ) the offset-Win kelwert is continuously subtracted from the angular value at the output of the counter ( 8 ), and that the difference value at the output of the totalizer ( 9 ) is present as the current difference between the computer system of the stations ( 2.1-2.3 ) Actual angle value can be fed.