Computerized control system for a carding machine

An electronic control system for a machine which forms fiber material into a length of silver which is delivered into a storage can, and which includes a carding cylinder, a feed roller for supplying fiber material to the cylinder, a doffer for removing a web of carded fibers from the cylinder and means for removing the carded fibers from the doffer and forming them into the length of fibers. The system includes monitoring devices for monitoring the operation of the machine, controllable regulator devices connected for controlling the operating speed of at least one of the doffer and feed roller, and a microcomputer connected to the monitoring devices and the regulator means for controlling the regulator devices.

BACKGROUND OF THE INVENTION 
The present invention relates to electronic machine control, for example 
for a carding machine or roller card wherein the type and quantity of 
fiber material processed is regulated and controlled. For example, the 
actual speeds of the feed roller and of an associated doffer are compared 
with given speed values stored in a memory and setting values are formed 
from the comparison result. The setting values are fed to the feed roller 
or to the doffer, respectively, so as to set a preselected delivery speed 
or a preselected draft. 
In a known carding machine, regulation and control of the type and quantity 
of fiber material processed is effected by a plurality of separate 
devices. For example, delivery speed and draft are each controlled by a 
separate electronic motor control for the drives of the feed roller and of 
the doffer. The regulation of the thickness of the sliver leaving the 
carding machine is effected, for example, independently thereof by way of 
a pneumatic signal fed to an electric three-point regulator which produces 
an electrical output signal to cause the fiber material fed into the 
carding machine to be regulated. All of this makes the system rather 
expensive. Moreover, various components, such as the electronic motor 
control and the three-point regulator, are subject to malfunction. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a control which avoids 
the above-mentioned drawbacks, which permits, in particular, central 
regulation and control of the type and quantity of fiber material 
processed and which, as a system, is less expensive and less subject to 
malfunction than prior art systems. 
The above and other objects are achieved, according to the present 
invention, by the provision of an electronic control system for a machine 
which forms fiber material into a length of sliver which is delivered into 
a storage can, and which includes a carding cylinder, a feed roller for 
supplying fiber material to the cylinder, a doffer for removing a web of 
carded fibers from the cylinder and means for removing the carded fibers 
from the doffer and forming them into the length of fibers, which system 
comprises: monitoring means for monitoring the operation of the machine; 
controllable regulator means connected for controlling the operating speed 
of at least one of the doffer and feed roller; and a microcomputer 
connected to the monitoring means and the regulator means for controlling 
the regulator means, the microcomputer comprising: 
data memory means for storing representations of desired values for the 
speeds of the doffer and feed roller and properties of the fiber material 
to be processed; 
program memory means storing a representation of the sequence of operations 
to be performed by the microcomputer; 
microprocessor means constituting a central processing unit and connected 
for controlling signal transfer to and from the memory means; 
interface logic means connected to the microprocessor means for transfer of 
signals therebetween and connected to the monitoring means for receiving 
information therefrom; 
input means connected to the interface means for the input of data and 
program information to be stored in the memory means; and 
output logic means connected between the interface logic means and the 
regulator means for supplying signals for controlling the regulator means; 
whereby the microcomputer means control the operation of the machine on the 
basis of the representations stored in the data and program memory means 
and the information provided by the monitoring means. 
In conjunction with the memory and the interface, the microprocessor forms 
a microcomputer in which the microprocessor, which operates between the 
memory and the interface, serves to develop the required calculation 
operations, logic decisions, instruction signals and the like, while 
external input signals such as keyboard signals and data regarding the 
respective machine state are converted in the interface and transmitted to 
the microprocessor, and instruction signals developed or existing in the 
microcomputer are transmitted to the external devices and control logic 
systems. 
According to the present invention, the speed, for example, of the feed 
roller and of the doffer are required by the microcomputer in conjunction 
with power converters, e.g. thyristors. 
A costly and malfunction prone electronic motor control is no longer 
necessary. Simultaneously, the necessary related functions, i.e. the 
matching of speed between feed roller, doffer and carding machine 
cylinder, are realized. Processing of the measured and setting signals for 
thickness regulation of the sliver is likewise effected by the 
microcomputer. The continuous monitoring of all significant measured 
values permits the early detection and localization of errors. In an 
advantageous manner, the microcomputer can simultaneously realize a direct 
speed regulation of the drive for the feed roller, the doffer, the tuft 
feed connected upstream, or the like. The use of an electronic three-point 
control is no longer required. 
Due to the ability of the microprocessor to store data, it is possible to 
store optimum values as determined once for a given lot, e.g. values for 
draft, delivery rate and the like, and to reuse such values for processing 
a similar lot if required, without the need for resetting so that no 
additional setting work is required when lots are changed. The regulating 
behavior for the drive motors is fixed by the program and can be varied at 
will, e.g. PI behavior, start-up integrator and the like. 
Other advantageous features are described below. 
By using a guide computer, various tasks can be performed: 
(a) error detection and localization (clear text) for carding master and 
the like; 
(b) compilation of operating data (dead times, production, breaks in the 
sliver, flaws); 
(c) information regarding maintenance, cleaning and repair work (operating 
hour counter); 
(d) for a group of cards as determined by the guide computer, all cards can 
be programmed or adjusted for a certain lot; 
(e) each individual carding machine can be corrected or influenced by the 
guide computer (production rate and the like). 
Because of the "intelligence" of the system, it is possible to act at once 
if there are any malfunctions and to prevent the occurrence of possibly 
disadvantageous effects, as shown by the following examples: 
Breaks in a conductor, operator errors or the like may provide an 
indication that 50,000 meters of sliver have been filled into a can but 
the system memory indicates that only 9000 m/can is accurate. Before the 
incorrect can fill of 50,000 m/can is put into operation, the guide 
computer or some other report inquires from the operator whether this 
value is correct. Only if the correctness is expressly confirmed, e.g. by 
a change in coilers, will the instruction be implemented. Information that 
a certain production rate belongs to a certain speed of the feed roller is 
also stored. If it is noted that the drive motor for the feed roller 
suddenly has a speed which exceeds the given limit, the machine is shut 
down at once and the error is reported, localized and possibly the 
situation is corrected automatically. Even if the speed of the cylinder 
drops, e.g. when it labors, this can also be detected, reported and 
evaluated at once. 
Of importance for the invention are the central control or regulation and 
control of all measuring, instruction and setting signals during 
processing of fiber material by the microcomputer, or microprocessor 
system. The microcomputer is thus used for regulating functions, e.g. 
regulation of the speed of the feed roller, of the doffer and the like. 
Additionally, the microcomputer is used for control functions, e.g. on/off 
switching of the carding machine or roller card, control of the velocity 
stages of the rollers, e.g. of the licker-in, the cylinder, the doffer for 
start-up movement, fast movement and slow movement and the like. 
The present invention will now be explained in greater detail with 
reference to embodiments that are illustrated in the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The control system shown in FIG. 1 has a microprocessor 1 as the central 
processing unit, CPU, connected on the one hand, with a data memory 2 and 
a program memory 3 and, on the other hand, with an interface 4. These 
control members 1 through 4 in their entirety constitute a microcomputer 
7. 
The memory 2 receives the data for the respective production program as fed 
in by the operator via a keyboard 5. Permanently programmed data for the 
sequence control for each production program are stored in the memory 3. 
These are data, inter alia, which permit or suppress certain machine 
functions upon the occurrence of certain determined operating states. 
These data determine, for example, the permissible speed range of the 
doffer. 
The microprocessor 1, on the one hand, produces all control signals 
required to operate the microcomputer and, on the other hand, performs, 
under control of the program stored in the PMEM memory 3, all data 
transfers between the memories and the external circuits and devices which 
are coupled in via the interface 4. Moreover, the microprocessor 1 makes 
all necessary calculations and decisions as will be explained below. 
The interface 4 is basically a buffer memory including input and output 
registers which make it possible to read into the microcomputer, upon 
instruction therefrom, external information as input signals, i.e. 
keyboard signals and signals which represent the machine state, and to 
read out the information stored therein, i.e. instructions, to transmit 
them as output signals to the external control logics, display devices and 
the like. 
The external devices include a display 6 with which the significant program 
data and, for example, information regarding the respective production 
rate and further machine states are displayed. Various sensors 8 generate 
reporting signals regarding the machine state. Such signals provide 
information, for example, as to whether the cylinder of the carding 
machine is running or not. 
Finally, there is provided a production, or control, logic system 9 with 
connected regulating motors 10 for the transport of material. During 
automatic operation, the logic system 9 receives its instruction signals 
from the microcomputer 7 and controls operation, for example, of the feed 
roller and of the doffer in dependence on the production program. 
As already mentioned above, the production programs are fed into the memory 
2 via an input device, e.g. the keyboard 5. The depression of a program 
key on keyboard 5 generates a code which is read into the microprocessor 1 
via the interface 4. The microprocessor determines whether the respective 
code represents an instruction, i.e. for example, storing, erasing or 
using a signal, or information for the production program. In the former 
case, the respective instruction is followed. If the microprocessor 1 
determines that an instruction signal means "store", it causes the last 
fed-in data to be transferred into memory 2. In the latter case, numbers 
or functions are intermediately stored in the data memory 2 for later use. 
FIG. 2 is a schematic representation of a carding machine which can be 
controlled according to the invention. This machine includes a feed roller 
11, a licker-in 12, a carding cylinder 13, a doffer 14, a stripper roller 
15, two pinch rollers 16 and 17, a trumpet 18 and two calender rollers 19 
and 20 which deliver a sliver. The feed roller 11 has an associated sensor 
in the form of an electronic tachogenerator 21 which is connected to an 
analog/digital converter 22. The analog/digital converter 22 is connected 
to the microcomputer 7, via its microprocessor interface 4 The 
analog/digital converter 22 is in turn controlled by the microcomputer 7. 
The microcomputer 7 is also associated with a desired value generator 
signal 23. 
The microcomputer 7 is connected to a first digital/analog power converter 
24 which is controlled by the microprocessor 1 and is in communication 
with a regulating motor 25 for driving the feed roller 11. The doffer 14 
similarly has an associated electronic tachogenerator 26 constituting a 
measured value sensor, which is connected to the analog/digital converter 
22. The microcomputer 7 is additionally connected to a second 
digital/analog power converter 27 which is in communication with the 
regulating motor 28 for the doffer 14. 
As will be apparent, elements 21, 22 and 26 of FIG. 2 form components of 
unit 8 of FIG. 1, while elements 24, 25, 27 and 28 of FIG. 2 form part of 
unit 10 of FIG. 1. 
During operation, the speeds of the feed roller 11 and of the doffer 14 are 
converted to speed-proportional analog electrical signals by the 
tachogenerators 21 and 26, respectively, which form input signals for the 
microcomputer 7. From the input signals and the stored program data, 
electrical output signals are developed via the microprocessor 1. These 
digital signals are converted back to analog electrical signals by the 
subsequent digital/analog power converters 24 and 27, respectively, and 
then are fed to the regulating motors 25 and 28, respectively by which the 
rotation of the feed roller 11 and the doffer 14, respectively, are 
controlled. 
FIG. 3 shows a control arrangement similar to that of FIG. 2 but 
constructed to perform additional regulating and control functions. The 
carding cylinder has an associated measured value sensor in the form of an 
electrical tachogenerator 30 which is connected to the analog/digital 
converter 22. Also connected to the analog/digital converter is a testing 
device 31. Finally, an analog signal is fed to the analog/digital 
converter from a sliver thickness measuring device 32 which will be 
described in greater detail with reference to FIG. 4. 
The following devices are further connected electrically to the 
microcomputer: 
operating elements, such as on/off switches for the carding machine and the 
like; a device 34 for the input of preliminary or primary signals, e.g. 
identifying the degree of can fill; monitoring members 35 which report 
malfunctions in the system, or in the operating sequence, respectively; a 
higher order guide computer 36 for a plurality of carding machines or 
roller cards; a programming module 37 with which variable data can be 
programmed once or when they change; a display device 38 to display 
production and counter states; and a control device 39, with which, for 
example, signal lights 40, relays 41 and valves 42 can be controlled 
directly. 
The digital/analog power converters 24 and 27 are in communication with the 
regulating motors 25 and 28 via devices 43 and 44, respectively. 
Device 43, 44 is, for example, a measuring device for motor current and/or 
motor voltage. To measure the motor current, for example, device 43, 44 
includes a shunt and an operational amplifier. The input signal is the 
motor current and/or the motor voltage. The output signal is an equivalent 
measurement signal (resulting from the measurement), the measurement of 
the motor current also producing a voltage as the output signal. 
As shown in FIG. 4, a sliver F passes through trumpet 18, thus producing a 
pneumatic signal x which is converted into an electrical signal y in a 
suitable transducer 45. In the analog/digital converter 22, the signal y 
is converted into a digital electric signal z, which is fed into the 
microcomputer 7 (see FIGS. 1 through 3). From this signal, an ouput signal 
is developed which serves to control, for example, the rotation of the 
feed roller 11 to vary the rate at which fibers are fed to the carding 
machine and thus to regulate the uniformity of the sliver leaving the 
carding machine. 
According to the invention it is possible, by using an electronic 
microcomputer control and regulating device, to eliminate the need for a 
considerable amount of apparatus previously required. In particular, the 
need for a separate control circuit with separate regulating device for 
each parameter to be regulated can be avoided. It should be noted, for 
example, that the power converters 27 are not regulating devices but, for 
example, are only power transistors which are actuated by corresponding 
pulses from the control device. The regulation of machine dependent and 
fiber technological data is no longer effected separately but together in 
the apparatus according to the invention. The particular advantage is that 
this links together the machine related and the fiber technological 
characteristics and enables them to act on one another. 
For example, the actual values from the sliver thickness measuring device 
can be processed in the control device and can be used as machine 
dependent control values for the speed of the feed roller and/or the 
doffer of the carding machine. Moreover, for example, the optimum fiber 
technological data, such as draft, production rate and the like can be 
measured for a certain lot of fibers and this information can be stored in 
the control device so that upon later processing of a similar lot the same 
machine-related control values can be set for the rollers of the carding 
machine. 
Finally, the necessary fiber technological data can be matched to the 
possible machine output and thus the relationship of carding technology to 
card structure can be optimized. A further advantage is that for other 
functions, e.g. the drive and/or the carding technology, a certain 
regulating behavior can be realized via desired, predeterminable 
characteristics. As a result, the information required for carding work, 
such as roller and doffer speeds, sliver thickness, speed ratios and the 
like, are centrally compiled, evaluated and processed in an optimum 
manner. 
FIG. 5 is a programming flow diagram illustrating the sequence of 
operations carried out by the microprocessor 1 according to a basic 
embodiment of the invention. As is the general practice in this art, the 
operating sequence is performed cyclically at a rate selected to assure 
that adjustments will be made sufficiently rapidly. Since variations in a 
carding process occur very slowly compared to conventional microprocessor 
cycle times, this requirement does not present any difficulty in the 
present case, particularly given the relatively small number of steps 
involved in a complete operating cycle. 
In the operating sequence depicted in FIG. 5, the first calculation block 
indicates that the desired and actual values for the speeds of the doffer 
14 and the feed roller 11 are determined based on values provided by the 
data memory 2 and the tachogenerators 21 and 26. The desired and actual 
values for the doffer speed are compared and the comparison result is 
supplied to the second control block. If equality does not exist, a new 
doffer speed control value is determined, as indicated by the second 
calculation block, to supply a control value which will bring the doffer 
speed to the desired value. The control value is supplied to power 
converter 27. 
If the actual and desired doffer speed values are found to be equal, or 
after determination of a new doffer speed control value, the result 
achieved by comparison of the actual and desired speed values for the feed 
roller are supplied to the second decision block. If this comparison 
result indicates that the values are not equal, a new feed roller speed 
control value is determined in the following calculation block, and the 
new control value is supplied to power converter 24. 
If the actual and desired speed values for the feed roller were found to be 
equal, or after determination of a new feed roller speed control value, 
the desired and actual sliver thickness values are stored. The desired 
value can be supplied from the data memory 2, while the actual sliver 
thickness value will be derived from regulator 45 via converter 22. These 
values are then compared and the comparison result is supplied to a 
further decision block. 
If this decision block indicates that the values are not equal, the last 
calculation block indicates that a new desired value for the doffer and/or 
feed roller speed is calculated. These calculations will, of course, be 
based on relationships between sliver thickness and doffer and feed roller 
speeds which are already well known in the art. The new desired value, or 
values, are then supplied to the first calculation block. If the last 
decision block indicates equality between the actual and desired sliver 
thickness values, the operating sequence returns to the input of the first 
decision block. 
Into the data memory 2 (see FIG. 1), of microcomputer 7 (see FIGS. 1 and 
3), signals are fed which represent the actual value recorded by the 
electrical tachogenerator 30 (see FIG. 1) serving as the measuring value 
sensor for the rpm of the drum 13 (see FIG. 2). 
Into the data memory 2 (see FIG. 1), signals are fed which represent the 
actual value of the motor current determined by the measuring device 43 
(see FIG. 3) for the drive of the feed roller 11 (see FIG. 2). 
Into the data memory 2 (see FIG. 1), signals are fed which represent the 
actual value of the motor current determined by the measuring device 44 
(see FIG. 3) for the drive of the doffer 14 (see FIG. 2). 
Into the data memory 2 (see FIG. 1), signals are fed which represent the 
motor voltage determined by the measuring device 43 (see FIG. 3) for the 
drive of the feed roller 11 (see FIG. 2). 
Into the data memory 2 (see FIG. 1), signals are fed which represent the 
actual value of the motor voltage determined by measuring device 44 (see 
FIG. 3) for the drive of the doffer 14 (see FIG. 2). 
Into the data memory 2 (see FIG. 1), signals are fed from a known testing 
device 31 (see FIG. 3). Such a testing device is known, for example, from 
the brochure "Pocket VDU--Fully Alphanumeric Hand-Held Terminal" by 
Neumunster Messtechnik. 
Into the data memory 2 (see FIG. 1) signals are fed from machines connected 
ahead of the carding machine (see FIG. 2) or the roller card, for example 
a tuft supplier 46 (see FIG. 3) as disclosed in U.S. Pat. No. 3,169,664 or 
U.S. Pat. No. 4,219,828 or a known fine opener. 
Into the data memory 2 (see FIG. 1), signals are fed from a machine 
connected downstream of the carding machine (see FIG. 2), for example from 
a drawing mechanism 47 as disclosed in U.S. Pat. No. 4,199,844 (see FIG. 
3). 
Into the data memory 2 (see FIG. 1), signals are fed from monitoring 
elements 35 (see FIG. 3), for example from a known motor protection 
switch. 
Into or out of the data memory 2 (see FIG. 1), signals are fed from and/or 
to a higher order known guide computer 36 (see FIG. 3), a higher order 
control or the like for plurality of cards or roller cards. 
Into or out of the data memory 2 (see FIG. 1) signals are fed from and/or 
to a known programming module 37 (see FIG. 3). Such a programming module 
is known, for example, from the brochure "Pocket VDU--Fully Alphanumeric 
Hand-Held Terminal" by Neumunster Messtechnik. 
Into or out of the data memory 2 (see FIG. 1), signals are fed from and/or 
for the machine operation 33 (see FIG. 3), for example known devices to 
switch on and off the carding machine or roller card. 
The invention includes control as well as regulating functions, i.e. 
control as well as regulating processes can be realized. 
It will be understood the above description of the present invention is 
susceptible to various modifications, changes and adaptations and the same 
are intended to be comprehended within the meaning and range of 
equivalents of the appended claims. 
FIG. 6 shows a similar flow diagram as FIG. 5. Here, the desired and given 
value for the doffer speed and the desired and given value for the feed 
roller speed are initially calculated. The results of this calculation are 
processed further in the same manner as shown in FIG. 5. In 
contradistinction to FIG. 5, after the last calculation box, the operating 
sequence returns to the input of the first decision box. While in FIG. 5 
actual values are determined in the first calculation box, at the input of 
FIG. 6 control values are calculated instead.