CA1268820A - Circuit testing - Google Patents
Circuit testingInfo
- Publication number
- CA1268820A CA1268820A CA000518930A CA518930A CA1268820A CA 1268820 A CA1268820 A CA 1268820A CA 000518930 A CA000518930 A CA 000518930A CA 518930 A CA518930 A CA 518930A CA 1268820 A CA1268820 A CA 1268820A
- Authority
- CA
- Canada
- Prior art keywords
- test meter
- display unit
- ohmic resistance
- electrical
- contacts
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000012360 testing method Methods 0.000 title claims abstract description 51
- 238000005259 measurement Methods 0.000 claims description 22
- 238000012544 monitoring process Methods 0.000 claims description 4
- 229910000831 Steel Inorganic materials 0.000 claims description 3
- 239000004973 liquid crystal related substance Substances 0.000 claims description 3
- 239000010959 steel Substances 0.000 claims description 3
- 238000010998 test method Methods 0.000 claims description 2
- 230000000694 effects Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
Landscapes
- Measurement Of Resistance Or Impedance (AREA)
Abstract
ABSTRACT OF DISCLOSURE
An electrical circuit test meter that includes a detachable meter reading display unit that displays a signal transmitted from the test meter body itself.
An electrical circuit test meter that includes a detachable meter reading display unit that displays a signal transmitted from the test meter body itself.
Description
:~6l~82~
~ his invention concerns electrical circuit testing, especiall~ testing of electrisal alarm circuitsO
5 ~ Conventional test meters are used for testing electrical circuitry. ~or faults by measuring resistance, voltage or current between two points and comparing the measurement with that when the circuit is in good working order. ~he use of a test meter is fairly simple in domestic equipment such as a television set. Eowever, problems arise when testing alarm circuits that have contacts at many points situated mainly some distance from a control unit for the alarm and often in separate rooms therefrom~ A person on.his own cannot test such alarm circuits since another person is required to make and break the contacts while the first person remains at the control panel to monitor the signal received and indicated b~ the test meter.
~he object of this invention..is to provide a test meter that ma7 be used by a single person to test electrical circuitr~ suca as alarm circuitry par-ticular wherein elec~rical contacts are remote ~rom the customary testing place na ely the control panel for t~e circui~.
According to this invention there is provided an 3 20228~287 electrical alarm circuit test meter/display unit combination, said electrical alarm circuit including a control box and one or more remote alarm contacts, comprising:
a test meter body for measuring ohmic resistance of the control box when connected thereto and when the circuit has no power applied thereto;
said test meter body including means for converting ohmic resistance measured into a radio freguency signal and means for transmitting said signal from said test meter body; and a receiver-display unit having means for receiving said signal transmitted from said test meter body transmitting means, including means for converting said signal back into said ohmic resistance measurement and means for displaying said resistance measurement at said remote alarm contacts for monitoring the ohmic resistance measurements displayed when acting on said remote contacts in turn which are indicative of the state of the remote alarm contact acted upon.
In accordance with another aspect of this inven-tion there is provided a method of testing an electrical alarm circuit which includes a control box and one or more remote alarm contacts, comprising:
connecting a test meter to the control box for measuring ohmic resistance at the control box when the circuit has no power applied thereto;
converting said test meter ohmic resistance measured into a radio frequency signal and transmitting said signal;
receiving said signal transmitted from said test meter at a receiver-display unit and converting said signal back into ~LZ~8~() -3a- 20228-287 said ohmic resistance measurement and displaying said resistance measurement at said remote alarm contacts; and acting on said remote contacts in turn and monitoring the ohmic resistance measurements displayed which are indicative of the state of the remote alarm contact being acted upon.
The test meter o-f the inventlon may, of course, be used as a conventional test meter with the detachable display unit attached to the meter body. However, for testing part of an electrical circuit remote from the conventional point o attachment of the test meter, such as the control panel for the circuit, the display unit is detached and taken to that remote part which can be operated and the effect on the meter at the control panel read on the detached display unit. Thus, one person can attach the test meter oE the lnvention to a control panel or other suitable part of an electrical circuit to be tested, detach the display unit and take it to any part of the circuit and note any change in reading, for example, when an electrical contact ls made or broken. The change in reading will ldentlfy if the contact is worklng correctly.
In the preferred embodiment, the test meter measures electrical resistance between two points of an electrical circuit.
That resistance measurement is converted into a radio Erequency signal that is transmitted from the meter body and is received by the detachable display unit which converts the signal back into a resistance .~
~ 61~
,; ` , measurement which is seen on the display unit.
Thus, the meter body preferably includes circuitry for converting a resistance measurement into a radio frequency signal and a radio frequency transmitter and an aerial or other suitable device therefor. The circuitry will preferably be powered by battery, al-though connection to mains supply is possible, and the battery ~, will preferably be rechargeable. The display unit then preferably has an aerial`or other radio frequency signal receiving means and electrical circuitry for converting the received signal back into a resistance measurement that is shown on the display unit.
The display unit may have any suitable display system, such as a movable needle over a marXed face, lS a light emitting diode display or preferably a liquid crystal display.
The meter body itself may include an on/off switch and may also include ohm range selection means such as a rotatable switch that can be turned to select an ohm range marked on the meter.
Mention has been made principally of resistance measurement but the test meter of the invention may also be one for measuring voltage and/or current. Indeed the meter may include means ror selecting ~he electrica parameter to be measured.
~2613~
As most control panels/boxes are at least~partly of metal, such as steel, it may be advantageous to provide the meter body with magnetic attachment means, such as one or more magnetic strips on the back of the -body where~y it can be attached to say a steel panel or box.
In practice then one person may with the test meter of the invention chec~; electrical circuitry that extends some way from the control point of the circuitrv. This is particularly useful for checking alarm circuits and for this purpose it is envisaged that the meter transmitter/receiver be able to operate over distances as much as lOOOm.
The invention will now be further described by way of example only, with reference to the accompanying drawings in which:-Figure 1 shows a test meter of the invention, and Figure 2 shows schematically the components of a test meter of the invention, Figure 3 shows a resistance measuring system ror a test meter of the invention, and Figure 4 shoWs schematically use of the meter of the invention.
Referring to Figures 1 and 2 or the draw~ngs a lZ~8"~ ~
test meter 10 comprises a main body 12 and a detachable display uni~ 14. The body 12 and display unit 14 have mutually engaging electrical contacts for conventional use of the meter with the display unit attached to the -body. Those contacts may provide the ~eans for retaining the display unit onthe body or other or additional releasable engagement means may be provided.
The body 12 contains a radio transmitter 16, an aerial 18 and electronic circuitry for converting a resistance measurement into a radio fxequency signal. The circuitry includes a resistance measuring system 20 and a data encoder 22 for converting the resistance measurement into radio freauency signals. The display uni~ 14 includes an aerial 24 for receiving the radio freauency signal from the meter body and electronic circuitry for converting the signal back into the resistance measurement. That circuitry includes a radio freauency receiver 26 and a data decoder 28. The measurement is then shown on liquid crystal display 30 through a glass window 32. Any other suitable display means may, of course, be used.
The resistance measuring system preferably includes a constant current circuit based on a differential amplifier 4 as shown in Figure 3, wherein the dotted lines represent the circuit under test and the connection a2 is .
~` 12~B~20 to the data encoder.
Connection of the meter to an electrical circuit is by means of wires 34 and 35 via probes 36 and 37 or alternatively via clip type endings.
The meter body is shown with an on/off switch 38 for the battery supply. The battery is preferably rechargeable so that means for co~nection thereof to a power supply may be provided. Also shown is a dial 40 by which the ohm range to be measured can be s~lected.
In use (see Figure 4 of the drawings), the meter 10 is connected to the control panel 51 o an electrical circuit 50, say an electrical alarm circuit that has a sexies of electrical contacts 52 that, ~or example, are made when a door is closed but broken when the door is opened. The door could be in another room or merely several yards away from the control painel 51 for the circuit 50 so that a second person would be needed using a conventional test meter, one person watching the meter whilst the other opens and closes the door. With the test meter of the invention, however, only one person is required who connects the meter to the control panel.
switches it on and detaches the display unit. That person can then take the display uni~ to the door and open and close the door while watching the display unit He can then tell by the resistanc2 readings that he obtains on the display unit if the contact is working 8 ~ 8 ~ ~
correctly. A whole alarm circuit can be tested in this way by one person without him ever having to return to the control panel.
This is almost certainly going to save time and - 5 expense as only one man can test an entire extensive electrical circuit re~atively quickly.
~ his invention concerns electrical circuit testing, especiall~ testing of electrisal alarm circuitsO
5 ~ Conventional test meters are used for testing electrical circuitry. ~or faults by measuring resistance, voltage or current between two points and comparing the measurement with that when the circuit is in good working order. ~he use of a test meter is fairly simple in domestic equipment such as a television set. Eowever, problems arise when testing alarm circuits that have contacts at many points situated mainly some distance from a control unit for the alarm and often in separate rooms therefrom~ A person on.his own cannot test such alarm circuits since another person is required to make and break the contacts while the first person remains at the control panel to monitor the signal received and indicated b~ the test meter.
~he object of this invention..is to provide a test meter that ma7 be used by a single person to test electrical circuitr~ suca as alarm circuitry par-ticular wherein elec~rical contacts are remote ~rom the customary testing place na ely the control panel for t~e circui~.
According to this invention there is provided an 3 20228~287 electrical alarm circuit test meter/display unit combination, said electrical alarm circuit including a control box and one or more remote alarm contacts, comprising:
a test meter body for measuring ohmic resistance of the control box when connected thereto and when the circuit has no power applied thereto;
said test meter body including means for converting ohmic resistance measured into a radio freguency signal and means for transmitting said signal from said test meter body; and a receiver-display unit having means for receiving said signal transmitted from said test meter body transmitting means, including means for converting said signal back into said ohmic resistance measurement and means for displaying said resistance measurement at said remote alarm contacts for monitoring the ohmic resistance measurements displayed when acting on said remote contacts in turn which are indicative of the state of the remote alarm contact acted upon.
In accordance with another aspect of this inven-tion there is provided a method of testing an electrical alarm circuit which includes a control box and one or more remote alarm contacts, comprising:
connecting a test meter to the control box for measuring ohmic resistance at the control box when the circuit has no power applied thereto;
converting said test meter ohmic resistance measured into a radio frequency signal and transmitting said signal;
receiving said signal transmitted from said test meter at a receiver-display unit and converting said signal back into ~LZ~8~() -3a- 20228-287 said ohmic resistance measurement and displaying said resistance measurement at said remote alarm contacts; and acting on said remote contacts in turn and monitoring the ohmic resistance measurements displayed which are indicative of the state of the remote alarm contact being acted upon.
The test meter o-f the inventlon may, of course, be used as a conventional test meter with the detachable display unit attached to the meter body. However, for testing part of an electrical circuit remote from the conventional point o attachment of the test meter, such as the control panel for the circuit, the display unit is detached and taken to that remote part which can be operated and the effect on the meter at the control panel read on the detached display unit. Thus, one person can attach the test meter oE the lnvention to a control panel or other suitable part of an electrical circuit to be tested, detach the display unit and take it to any part of the circuit and note any change in reading, for example, when an electrical contact ls made or broken. The change in reading will ldentlfy if the contact is worklng correctly.
In the preferred embodiment, the test meter measures electrical resistance between two points of an electrical circuit.
That resistance measurement is converted into a radio Erequency signal that is transmitted from the meter body and is received by the detachable display unit which converts the signal back into a resistance .~
~ 61~
,; ` , measurement which is seen on the display unit.
Thus, the meter body preferably includes circuitry for converting a resistance measurement into a radio frequency signal and a radio frequency transmitter and an aerial or other suitable device therefor. The circuitry will preferably be powered by battery, al-though connection to mains supply is possible, and the battery ~, will preferably be rechargeable. The display unit then preferably has an aerial`or other radio frequency signal receiving means and electrical circuitry for converting the received signal back into a resistance measurement that is shown on the display unit.
The display unit may have any suitable display system, such as a movable needle over a marXed face, lS a light emitting diode display or preferably a liquid crystal display.
The meter body itself may include an on/off switch and may also include ohm range selection means such as a rotatable switch that can be turned to select an ohm range marked on the meter.
Mention has been made principally of resistance measurement but the test meter of the invention may also be one for measuring voltage and/or current. Indeed the meter may include means ror selecting ~he electrica parameter to be measured.
~2613~
As most control panels/boxes are at least~partly of metal, such as steel, it may be advantageous to provide the meter body with magnetic attachment means, such as one or more magnetic strips on the back of the -body where~y it can be attached to say a steel panel or box.
In practice then one person may with the test meter of the invention chec~; electrical circuitry that extends some way from the control point of the circuitrv. This is particularly useful for checking alarm circuits and for this purpose it is envisaged that the meter transmitter/receiver be able to operate over distances as much as lOOOm.
The invention will now be further described by way of example only, with reference to the accompanying drawings in which:-Figure 1 shows a test meter of the invention, and Figure 2 shows schematically the components of a test meter of the invention, Figure 3 shows a resistance measuring system ror a test meter of the invention, and Figure 4 shoWs schematically use of the meter of the invention.
Referring to Figures 1 and 2 or the draw~ngs a lZ~8"~ ~
test meter 10 comprises a main body 12 and a detachable display uni~ 14. The body 12 and display unit 14 have mutually engaging electrical contacts for conventional use of the meter with the display unit attached to the -body. Those contacts may provide the ~eans for retaining the display unit onthe body or other or additional releasable engagement means may be provided.
The body 12 contains a radio transmitter 16, an aerial 18 and electronic circuitry for converting a resistance measurement into a radio fxequency signal. The circuitry includes a resistance measuring system 20 and a data encoder 22 for converting the resistance measurement into radio freauency signals. The display uni~ 14 includes an aerial 24 for receiving the radio freauency signal from the meter body and electronic circuitry for converting the signal back into the resistance measurement. That circuitry includes a radio freauency receiver 26 and a data decoder 28. The measurement is then shown on liquid crystal display 30 through a glass window 32. Any other suitable display means may, of course, be used.
The resistance measuring system preferably includes a constant current circuit based on a differential amplifier 4 as shown in Figure 3, wherein the dotted lines represent the circuit under test and the connection a2 is .
~` 12~B~20 to the data encoder.
Connection of the meter to an electrical circuit is by means of wires 34 and 35 via probes 36 and 37 or alternatively via clip type endings.
The meter body is shown with an on/off switch 38 for the battery supply. The battery is preferably rechargeable so that means for co~nection thereof to a power supply may be provided. Also shown is a dial 40 by which the ohm range to be measured can be s~lected.
In use (see Figure 4 of the drawings), the meter 10 is connected to the control panel 51 o an electrical circuit 50, say an electrical alarm circuit that has a sexies of electrical contacts 52 that, ~or example, are made when a door is closed but broken when the door is opened. The door could be in another room or merely several yards away from the control painel 51 for the circuit 50 so that a second person would be needed using a conventional test meter, one person watching the meter whilst the other opens and closes the door. With the test meter of the invention, however, only one person is required who connects the meter to the control panel.
switches it on and detaches the display unit. That person can then take the display uni~ to the door and open and close the door while watching the display unit He can then tell by the resistanc2 readings that he obtains on the display unit if the contact is working 8 ~ 8 ~ ~
correctly. A whole alarm circuit can be tested in this way by one person without him ever having to return to the control panel.
This is almost certainly going to save time and - 5 expense as only one man can test an entire extensive electrical circuit re~atively quickly.
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Electrical alarm circuit test meter/display unit combination, said electrical alarm circuit including a control box and one or more remote alarm contacts, comprising:
a test meter body for measuring ohmic resistance of the control box when connected thereto and when the circuit has no power applied thereto;
said test meter body including means for converting ohmic resistance measured into a radio frequency signal and means for transmitting said signal from said test meter body; and a receiver display unit having means for receiving said signal transmitted from said test meter body transmitting means, including means for converting said signal back into said ohmic resistance measurement and means for displaying said resistance measurement at said remote alarm contacts for monitoring the ohmic resistance measurements displayed when acting on said remote contacts in turn which are indicative of the state of the remote alarm contact acted upon.
a test meter body for measuring ohmic resistance of the control box when connected thereto and when the circuit has no power applied thereto;
said test meter body including means for converting ohmic resistance measured into a radio frequency signal and means for transmitting said signal from said test meter body; and a receiver display unit having means for receiving said signal transmitted from said test meter body transmitting means, including means for converting said signal back into said ohmic resistance measurement and means for displaying said resistance measurement at said remote alarm contacts for monitoring the ohmic resistance measurements displayed when acting on said remote contacts in turn which are indicative of the state of the remote alarm contact acted upon.
2. An electrical circuit test meter as claimed in claim 1, wherein the display unit display comprises a movable needle over a marked face.
3. An electrical circuit test meter as claimed in claim 1, wherein the display unit display is a light emitting diode display.
4. An electrical circuit test meter as claimed in claim 1, wherein the display unit display is a liquid crystal display.
5. An electrical circuit test meter as claimed in claim 1, wherein the meter body is provided with magnetic attachment means, whereby it can be attached to say a steel panel or box.
6. An electrical circuit test meter as claimed in claim 1, wherein said display unit body is detachably mounted to said meter body.
7. A method of testing an electrical alarm circuit which includes a control box and one or more remote alarm contacts, comprising:
connecting a test meter to the control box for measuring ohmic resistance at the control box when the circuit has no power applied thereto;
converting said test meter ohmic resistance measured into a radio frequency signal and transmitting said signal;
receiving said signal transmitted from said test meter at a receiver-display unit and converting said signal back into said ohmic resistance measurement and displaying said resistance measurement at said remote alarm contacts; and acting on said remote contacts in turn and monitoring the ohmic resistance measurements displayed which are indicative of the state of the remote alarm contact being acted upon.
connecting a test meter to the control box for measuring ohmic resistance at the control box when the circuit has no power applied thereto;
converting said test meter ohmic resistance measured into a radio frequency signal and transmitting said signal;
receiving said signal transmitted from said test meter at a receiver-display unit and converting said signal back into said ohmic resistance measurement and displaying said resistance measurement at said remote alarm contacts; and acting on said remote contacts in turn and monitoring the ohmic resistance measurements displayed which are indicative of the state of the remote alarm contact being acted upon.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000518930A CA1268820A (en) | 1986-09-25 | 1986-09-25 | Circuit testing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000518930A CA1268820A (en) | 1986-09-25 | 1986-09-25 | Circuit testing |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1268820A true CA1268820A (en) | 1990-05-08 |
Family
ID=4134007
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000518930A Expired CA1268820A (en) | 1986-09-25 | 1986-09-25 | Circuit testing |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1268820A (en) |
-
1986
- 1986-09-25 CA CA000518930A patent/CA1268820A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed | ||
| MKEC | Expiry (correction) |
Effective date: 20121205 |