GB2228641A

GB2228641A - Measuring instrument

Info

Publication number: GB2228641A
Application number: GB8904481A
Authority: GB
Inventors: Edward Smithson
Original assignee: Megger Instruments Ltd
Current assignee: Megger Instruments Ltd
Priority date: 1989-02-28
Filing date: 1989-02-28
Publication date: 1990-08-29
Anticipated expiration: 2009-02-28
Also published as: GB2228641B; GB8904481D0

Abstract

A measuring instrument for measuring a variable electrical parameter such as voltage in which instrument the parameter is read and coded by a suitable means such as a microprocessor 1 which controls a sound or light emitter 15, a reader preferably a bar code reader (18 Fig. 2) is provided to read a coded emission corresponding to the parameter. The parameter is preferably displayed on a digital display 13. The instrument is convenient for reading voltages, consumption and soon at various points by means of the suitable reader (18) which can then off load its readings to a logging device. <IMAGE>

Description

MEASURING INSTRUMENT The present invention relates to measuring instruments.

Measuring instruments for measuring and recording variable parameters such as weight, electrical resistance, voltage, electrical or gas consumed units, temperature or liquid flow have been traditionally displayed in an analogue or digital form.

In order to log such instruments it has been the practice for this to be done manually or by means of a connected logging device.

In certain applications it may be necessary where there are several similar instruments, that logging is done by multiple connections or by plugging or unplugging the logging device. This may be inconvenient in the event of the instruments being widely separated and in sore conditions where high voltages exist it may be undesirable to have direct connections. Telemetry is sometimes used, but this has its problems.

A measuring instrument according to the present invention comprises means for reading a variable parameter, parameter coding means for producing a coded signal corresponding to the reading, a light or sound emitter arranged to emit externally from the instrument, and control means for causing the light or sound emission to be emitted in accordance with the coded signal.

Preferably the reading means includes an input conditioning module and analogue to digital convertor.

The control means suitably comprises a microprocessor which may also include the coding means.

The input conditioning module is preferably controlled from the microprocessor and is arranged to adjust the input ranging.

The analogue/digital convertor is arranged to convert a scaled analogue signal from the input conditioning module to a digital signal for the microprocessor.

Preferably a digital display is connected to the microprocessor for displaying the reading from the input. The display may also be a cathode ray tube or other analogue display.

The light or sound emitting means may be a light emitting diode (LED) which is connected to the microprocessor. The LED is controlled to cause the light signal coded in accordance with the coded signal generated by the microprocessor. The coded signal represents the read value and is suitably a pulse train in the form of a timewise bar code digital representation which can be read by a bar code reader.

Bar code readers are now cheap and therefore any logging by such a means would be adaptable, cost effective and overcome the problems of fixed logging devices. In high power or hazardous areas the use of light and acoustic receiver and transmitters would be safe.

In order to log the station or instrument number these can have a bar code indicator capable of being wiped by the reader in the normal way. Such an indicator would be a fixed parameter for the instrument.

The use of a bar code system would have further advantages that the logging instrument can be arranged to read different units from different instruments by coding the unit to be emitted into the serial number indicator.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a block diagram of one instrument according to the invention and Figure 2 is a schematic diagram of the instrument of Figure 1.

A typical measuring instrument 2 according to the invention is shown in Figure 1 comprising a microprocessor 1, a key pad 3 connected to inputs on the microprocessor so that the user can control the instrument via the microprocessor. An input conditioning module 5 is controlled from the microprocessor through control lines 7 so that the input ranging may be adjusted. The input conditioning module 5 is connected to test terminals 9 and an analogue to digital convertor 11 is connected between the input conditioning module and the microprocessor to convert a variable parameter signal at the test terminals to a digital signal for the microprocessor.

Connected to the microprocessor is a meter display 13 which may be a digital liquid crystal display or else a cathode ray tube or simple analogue display for displaying a final measured value of the variable parameter.

Also connected to the microprocessor is a simple pulsing light emitting means 15 such as a LED which is controlled to emit a coded signal in the form of a time spaced signal and which is suitably coded according to a bar code.

In an alternative form of the instrument the light emitting means may be a sound emitting means.

In Figure 2 the instrument 2 of Figure 1 has its light emitting means 15 and a bar code strip at 17. A bar code reader 18 with a bar code pick up 20 and display 22 is provided to read a fixed parameter that is the serial number of the instrument 2. A further bar code strip 24 on an item 26 to be tested may indicate the serial number of item 26 and if necessary the units to read through instrument 2.

A log book or manual 28 may also be provided with a bar code strip 30 indicating a catalogue or account number.

To use the instrument 2 it is simple to wipe pick up 20 over log book bar code strip 30 to indicate to reader 18 the item type or account number. The pick up 20 is then wiped over the bar code strip 17 of instrument 2 to check the identification of instrument 2. Instrument 2 is set to emit from L.E.D. 15 a bar coded signal corresponding to the reading of instrument 2. The pick up 20 is then held so as to receive the light emitted pulses of L.E.D.

15 so that the reader 18 can log the reading taken at terminals 9.

Whilst L.E.D. 15 emits visible light, infra red or ultra violet light may be used to transmit the coded variable parameter. Other coding than bar codes may be used but bar coding is preferred because this can be simply read by readily available readers.

Claims

1. A measuring instrument comprising means for reading a variable parameter, parameter coding means for producing a coded signal corresponding to the reading, a light or sound emitter arranged to emit externally from the instrument, and control means for causing the light or sound emission to be emitted in accordance with the coded signal.

2. A measuring instrument as claimed in claim 1 including an input conditioning module and analogue to digital convertor.

3. A measuring instrument as claimed in claim 2 wherein the control means comprises a microprocessor.

4. A measuring instrument as claimed in any one of claims 1 to 3 wherein the control means includes the coding means.

5. A measuring instrument as claimed in claim 3 wherein the input conditioning module is controlled from the microprocessor and is arranged to adjust the input ranging.

6. A measuring instrument as claimed in claim 3 or 5 wherein the analogue to digital convertor is arranged to convert a scaled analogue signal from the input conditioning module to a digital signal for the microprocessor.

7. A measuring instrument as claimed in claim 3, 5 or 6 wherein a digital display is connected to the microprocessor for displaying the reading from the input.

8. A measuring instrument as claimed in any one of claims 1 to 7 wherein the light or sound emitting means is a light emitting diode connected to the control means.

9. A measuring instrument as claimed in any one of claims 1 to 8 wherein the light or sound emitting means is a light emitting means emitting the coded signal in the form of a pulse train.

10. A measuring instrument substantially as hereinbefore described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows 1. A measuring instrument comprising means for reading a variable electrical analogue parameter, parameter coding means for producing a coded signal corresponding to the reading, a light or sound emitter arranged to emit externally from the instrument, and control means for causing the light or sound emission to be emitted in accordance with the coded signal.