GB2116796A

GB2116796A - Data input arrangement

Info

Publication number: GB2116796A
Application number: GB8206878A
Authority: GB
Inventors: Leslie A Birt; David A Bonham; Anthony D Grimer
Original assignee: Bowthorpe Holding PLC
Current assignee: Bowthorpe PLC
Priority date: 1982-03-09
Filing date: 1982-03-09
Publication date: 1983-09-28
Also published as: GB2116796B

Abstract

A data input arrangement comprises an e.g. rotary element 10 manually movable over a predetermined range along a predetermined path, means (such as a wiper 12 co-operating with a potentiometer 14) for detecting the instantaneous position of the element 10, and a digital display 22 arranged to give a digital indication of the position of the element 10. No values scale is required in association with the control element 10, because the digital display gives an immediate and accurate display of the value selected for data input into the system memory. <IMAGE>

Description

SPECIFICATION Data input arrangement This invention relates to an arrangement for the input of data, for example into a microprocessor system.

In accordance with this invention there is provided a data input arrangement, comprising an element manually movable over a predetermined range along a predetermined path, means for detecting the instantaneous position of said element, and a digital display arranged to give a digital indication of the position of said element.

Preferably means are provided (such as a selector switch or a bank of push buttons) for selecting amongst different parameters in respect of which data is to be input or loaded.

Each parameter generally has a valid range, values outside of which are invalid, and conveniently each valid range is arranged to correspond with the full, predetermined range of movement of the input element.

This input element may be movable along a linear track or over an arcuate track, for example, but a particularly convenient arrangement comprises a rotary input element.

The input element may drive the wiper of a potentiometer itself driving an analogue-todigital converter feeding a microprocessor. Instead of using a different potentiometer for each of the selectable parameters, the same potentiometer may be used for all parameters with the microprocessor controlling the digital display according to the selected parameter and its valid range of values. Thus the relationship between the wiper position and the data value being input is determined by the microprocessor. The input range may be linear (with respect to the position of the movable input element) between upper and lower values of the parameter. However, different profiles can be used for the different parameters: some could be reversed low to high and others non-linear e.g. logarithmic.

An embodiment of this invention will now be described, by way of example only, with reference to the accompanying drawing, the single figure of which is a schematic diagram of a data input arrangement in accordance with the invention.

The data input arrangement illustrated comprises a rotary input control 10 which is manually movable and drives a wiper 1 2 of a rotary potentiometer 1 4 having a potential difference connected across it. The wiper is fed to an analogue-to-digital converter 1 6 itself feeding a microprocessor 1 8. A bank of selector push buttons 20 is provided for selecting amongst parameters for which data is to be entered, and a digital display 22 is provided for indicating the value being loaded.

The rotary position of the control 10 determines the voltage appearing on the potentiometer wiper (for a given value of potential difference across the potentiometer ends), and hence the digital value issued by the converter 1 6. The microprocessor is able to determine the position of the wiper from this digital value and from the known value of the potential difference across the potentiometer. According to the parameter selected by the push-buttons 20, the valid range of values for that parameter is related to the range of movement of the rotary control and the parameter value is displayed digitally on the display 22. The user may simply adjust the rotary control (and hence the position of the potentiometer wiper) until the display 22 shows the data value which it is desired to enter.

Thus the adjustment of the rotary control produces the data value to be entered. The microprocessor, with its preset relationship between potentiometer range and selected parameter range, formats the data and only allows valid values (for example it would not allow 26 o'clock or 3 Ibs 1 7 oz). The microprocessor might be arranged to enter time to the nearest e.g. 10 minutes, or to enter only values between 20 and 60 minutes for example. Moreover, the arrangement renders it impossible for the user to enter a value which is too precise or too imprecise (to too many or to too few decimal places, for example).

In the arrangement illustrated, the microprocessor is arranged to detect when a parameter is selected on the bank of push-buttons 20, in response to which it causes a display of the existing value of that parameter as held in its memory, regardless of the actual position of the rotary control 10 at that time. The microprocessor repeatedly reads the wiper position (via the analogue-to-digital converter): whilst this position remains unchanged the microprocesor drives the display to show the value currently stored in the memory. However, the microprocessor is arranged to sense a change (of at least a small amount) in position of the wiper so as to drive the display to show a value related to the instantaneous position of the wiper and this value is substituted in the memory. This value is continuously updated as the rotary control is moved: when the depressed push-button is released the displayed value at that time is held in the memory. Thus existing values can be read without losing them and new entries or changes can be made without the need to clear old values. If a parameter selecting push-button is not held down, changes in the position of the wiper do not up-date the value stored in the memory, and thus held data is protected against corruption due to any accidental movement of the rotary control.

There is no need for any legend or scale (which would be very complex for a multi parameter usage) to co-operate with the rotary control to indicate its position, because the data value being entered is displayed digitally.

Claims

1. A data input arrangement, comprising an element manually movable over a predetermined range along a predetermined path, means for detecting the instantaneous position of said element, and a digital display arranged to give a digital indication of the position of said element.

2. A data input arrangement as claimed in claim 1, further comprising means for selecting amongst different parameters in respect of which data is to be input.

3. A data input arrangement as claimed in claim 2, in which for each said parameter a full valid range thereof corresponds with the full predetermined range of movement of said input element.

4. A data input arrangement as claimed in any preceding claim, in which said input element is a rotary input element.

5. A data input arrangement as claimed in any preceding claim, in which said input element drives the wiper of a potentiometer itself driving an analogue-to-digital converter.

6. A data input arrangement as claimed in any preceding claim, further comprising a data memory with means for recalling to said display data stored therein and the arrangement being such as to up-date the displayed data upon movement of said element.

7. A data input arrangement as claimed in any preceding claim, further comprising a microprocessor serving to disallow (for input) data of invalid values.

8. A data input arrangement substantially as herein described with reference to the accompanying drawing.