GB2269468A

GB2269468A - Control of electronically-triggerable devices

Info

Publication number: GB2269468A
Application number: GB9316055A
Authority: GB
Inventors: Harald Eckel; Manfred Gruener; Berthold Loew
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1992-08-05
Filing date: 1993-08-03
Publication date: 1994-02-09
Anticipated expiration: 2013-08-03
Also published as: GB9316055D0; FR2694646B1; FR2694646A1; DE4226236C1; GB2269468B

Abstract

Apparatus far the control of electronically triggerable means, e.g. matrix print needles, arranged on a rectilinearly reciprocated carriage comprises an incremental transmitter (1) which generates a step clock signal (1a) by way of a synchronisation logic (2) into a control logic (3). The control logic (3) is connected to a variable fine-step timer (5). The fine-step clock signals (7) of the fine-step timer (5) can be passed on to a fine-step counter (8) as well as to at least one triggering clock generator (9, 10). When the count value of a triggering clock generator register (12) is reached, a triggering clock signal (11) can be generated. This allows a highly accurate triggering of the electronic means even during an irregular movement of the carriage. <IMAGE>

Description

2269468 APPARATUS FOR THE CONTROL OF ELECTRONICALLY TRIGGERABLE DEVICES

This invention relates to an apparatus for the control of electronically triggerable devices, in particular such devices when carried on a moving carriage such as a rectilinearly reciprocated carriage, sliding carriage or the like.

German Patent No. 1 129 595 describes a control apparatus with an incremental transmitter which generates a clock signal or pulse for the control of the means to be triggered, a microprocessor for the transfer of register data and with a fixed length division of the path which is covered by the carriage, sliding carriage or the like. In this known numerical control of machines, in particular machine tools, the accuracy of control depends upon the resolving capacity of the path length by pulses. In this respect it is proposed to undertake a rough measurement by a digital path measurement and a fine measurement by a time measurement. It is, however, conceded that the known arrangement cannot detect fluctuations in speed, since it is known to graduate the pulse intervals, obtained by photoelectric scanning of a graduation grid, by a linear time interpolation. Such an interval graduation serves, in this respect, primarily for the measurement of the fluctuation in speed occurring in the case of machine tools.

2 A control apparatus f or a mosaic printer is known from German Patent No. 30 14 338 with a microprocessor and a supply of information for a predeterminable print spacing of a printing raster or scanner linked to constant path intervals of the movement of a printing carriage and f or an answer-back signal raster coming f rom an answer-back signal device, the path interval being greater than the print spacing. Here a start is made from a path distance following a preceding answer-back signal, an average speed being ascertainable from an earlier path interval and a time measured during the covering of this path interval.

However, this control too is no longer adequate for the increased demands made on the accuracy of electronically triggerable means, such as e.g. printing elements in matrix printers.

An object of the invention is the provision of an apparatus which allows detection of fluctuations in speed and thus achieves a highly accurate control of electronically triggerable means.

Apparatus for the control of electronically triggerable devices which are arranged on a moving carriage, having an incremental transmitter which generates a step clock signal for the control of the devices to be triggered, the step clock signal delivered by the incremental transmitter being transmitted to a control logic by way of a synchronisation logic and the control logic being connected to a variable 3 f ine-step timer, wherein the f ine-step clock signals of the timer are passed to a fine-step counter and to at least one triggering clock generator operable to generate a triggering clock signal when a count value of a triggering generator register is reached,.

The apparatus includes a microprocessor for the transfer of register data. The path covered by the carriage is divided into fixed length divisions.

The advantages achieved include especially an extremely accurate splitting of a predetermined length of path, in which respect the reference signal can be an incremental transmitter or motion pick-up. The division produced with the variable timer can constantly be adapted to the frequency of the incremental transmitter.

By virtue of the arrangement with each synchronised incremental 11clockel. i.e. step clock- signal of the incremental transmitter, one or more possibly missing "fine-step clocks" are produced at fairly short intervals, if the speed is too high, or no "fine-step clocks" are produced in the case of too slow a speed. In this respect it is advantageous that the number of "fine-step clocks" over the entire length of path in the case of the predetermined data is always of the same- magnitude.

Advantageously, the triggering clock generator is initially 4 loaded with a valve which is equal to or smaller than the value of the triggering clock generator register.

Furthermore, the f ine-step counter may be variable with respect to a step clock of the incremental transmitter, i.e. it can be resolved into any desired number of f inestep clocks.

The invention will now be further described by way of example with reference to the accompanying drawings, in which:

Fig. 1 is a block diagram of an apparatus in accordance with the invention; Fig. 2 is a further break-down of the block diagram of Fig. 1, and Figs. 3 to 8 show the pulse curves for: Start/Stop (Fig. 3); Incremental clock (Fig. 4); Micro-clock (Fig. 5); Fine-step clock (Fig. 6); Triggering clock for first electronically triggerable means (Fig. 7), and, Triggering clock for a second electronically triggerable means (Fig. 8).

The control apparatus may be used with a reciprocating carriage, sliding carriage or the like being e.g. a printing head sliding carriage of a matrix needle printer. The apparatus includes an incremental transmitter 1, here shown as a so-called clock disc with signal transmitter.

The incremental transmitter 1 transfers its step clock signals la to a synchronisation logic 2, - which is connected signalwise to a control logic 3. The input of a Start or Stop signal 4 is effected by way of the control logic 3.

As a result of a Start signal 4, a counter in a fine-step timer 5 is started. A micro-clock 6, derived from a frequency oscillator, clocks the counter of the fine-step timer 5 until the predetermined value of a register 5a is reached in the fine-step timer 5. When this value is reached, at the same time a fine-step clock 7 is triggered, which increments a fine-step counter 8, sets the counter in the fine-step timer 5 to "zero" and increments other counters in triggering clock generators 9 and 10, discussed further below.

The fine-step counter 8 possesses a fine-step limitation register 8a and a fine-step limitation control 8b. In the same way the fine-step timer 5 has a fine-step time register 5a and a fine-step controller 5b. The number of fine-step clocks 7 within the time between two increments of the incremental transmitter 1 is contained in the finestep limitation register 8a.

6 The procedure which generates the fine-step clocks continues to run until the fine-step counter 8 has reached the value of the fine-step limitation register 8a, unless previously stopped by a synchronised step clock la of the incremental transmitter 1 in this routine. With identical values in the fine-step counter 8 and fine-step limitation register 8a, the fine- step clock generation is halted, until a new synchronised step clock starts the same procedure from the beginning.

If, before the valves of the f ine-step counter 8 and of the fine-step limitation register 8a reach equality, a synchronous step clock la of the incremental transmitter 1 occurs, the fine-step counter 8 is incremented with the micro-clock 6 until there is equality of the fine-step limitation register 8a and of the fine-step limitation control 8b, in which case also correspondingly just as many fine-step clocks 7 are generated and the fine-step counter 8, as well as. the counter in the f ine-step, timer 5, are again set to "zero". The same procedure begins immediately after the step clock la of the incremental transmitter 1.

With each fine-step clock 7, counters in the connected triggering clock generators 9 and 10 are incremented.

Upon equality of a counter and of a register in the triggering clock generators 9 and 10 being reached, triggering clock 11 is generated and the counters then 7 begin again at "zero".

The triggering clocks 11 can be transferred e.g. to timers in the circuits f or the triggering of a printing needle, driven by an electromagnet, in matrix needle printing heads.

In Fig. 3, the Start/Stop signal 4 during the control procedure is on logic 11111. The step clock la of the incremental transmitter 1 is depicted true-to-scale in Fig. 4. Fig. 5 shows the micro-clock 6 derived from a frequency oscillator of e.g. 1 or 2 MHz. The fine-step clock 7 (Fig. 6) is, as an example, adjusted with f ive micro-clocks 6, which are deposited in the fine-step time register 5a.

The step clock la depicted third from the left comes temporally, at a shorter interval after the nominally predetermined Interval, e.g. on account of rapid running of an electric motor which drives the clock disc and which also drives the carriage, sliding carriage or the like.

In this case, supplementary fine-step clocks 7 have to be generated. The step clock signal la, depicted fourth from the left, comes temporally at a longer interval after the nominally predetermined interval, e.g. on account of the electric motor running too slow. Thus, the number of finestep clocks 7 within a step clock la remains constant.

8 Furthermore, a triggering clock generator register 12 is provided, see Figs. 1 and 2, which, each time the predetermined register value.is reached, can deliver the triggering clock 11. In the triggering clock generator 9 initially a value can be loaded with is already equal to or smaller than the value of the triggering clock generator register 12, so that, prior to the otherwise normal arrival at the register value, a triggering clock 11 is generated. In contrast, Fig. 7 shows the otherwise normal arrival at the register value. In this respect, for example, the triggering clock 11 is resolved into seven counting values. In Fig. 8 the embodiment with a non-normal register value is presupposed. In Figs. 7 and 8 the counting values are plotted at the bottom.

9

Claims

CLAIMS:

1. Apparatus for the control of electronically triggerable devices which are arranged on a moving carriage, having an incremental transmitter which generates a step clock signal for the control of,,the devices to be triggered, the step clock signal delivered by the incremental transmitter being transmitted to a control logic by way of a synchronisation logic and the control logic being connected to a variable fine-step timer, wherein the f ine-step clock signals of the timer are passed to a f ine- step, counter and to at least one triggering clock generator operable to generate a triggering clock signal when a count value of a triggering generator register is reached.

2. Apparatus as claimed in Claim 1, wherein a value is initially loaded into the triggering clock generator(s) which is equal to or smaller than the value of the triggering clock generator register.

3. Apparatus as claimed in either Claim 1 or Claim 2, wherein the finestep counter is variable with respect to a step clock signal of the incremental transmitter.

4. Apparatus substantially as hereinbefore described and illustrated in the accompanying drawings.