GB2594722A

GB2594722A - Weld monitoring apparatus

Info

Publication number: GB2594722A
Application number: GB2006623.9A
Authority: GB
Inventors: Aherne Mark
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-05-05
Filing date: 2020-05-05
Publication date: 2021-11-10
Anticipated expiration: 2040-05-05
Also published as: GB202006623D0; GB2594722B

Abstract

Current is monitored in a weld apparatus, and subsequently integrated (e.g. deriving the energy used). User operable scaling control 102 and scaling circuitry can scale the current or integrated value. Comparator circuitry can compare the scaled integrated value with reference values and indicate the comparison. An operator may set the scaling circuitry using dials, 104, 106. Exemplary, good quality teaching welds can be performed initially; with current, energy and power values being monitored/stored. Subsequent welds may be compared to the exemplary welds, using the scaling setting, to indicate to the user, e.g. using LEDs 114, 116, how the subsequent weld compares to the teaching welds. Current and/or voltage amplifying and/or filtering circuitry may be used. A representative signal may be indicative of the power delivered to a weld. The scaled integrated value may be indicative of the energy delivered to a weld. Integrating may start and stop using trigger circuitry.

Description

WELD MONITORING APPARATUS

The present invention relates to weld monitoring apparatus and to methods of weld monitoring.

Welding is a process for joining together parts, such as metallic parts, which typically comprises generating heat in the region of a join in order to melt the parts, and then allowing the region of the join to cool so as to fuse the parts together. In some forms of welding, such as arc welding and resistance welding, the heat is generated using electrodes, which apply a voltage across the parts to be joined in order to pass a current through those parts. The quality of the weld is largely dependent on the amount of energy applied, which in turn is largely dependent on the voltages and currents used during the welding process and the types of materials to be welded. It is known to use weld monitoring apparatus to sample the voltages and currents used during a welding process, and then to determine whether those sampled values are consistent with desired values for a high-quality weld. However, the known weld monitoring apparatus can be highly complex to operate and can be expensive to manufacture. Furthermore, the known weld monitoring apparatus require frequent specialist calibration using known absolute voltages and currents in order to operate accurately, and require the user to have knowledge of the desired absolute values for high-quality welds, typically in SI units, such as amps, volts, joules and watts, and these can vary considerably, for example based on the particular type of materials to be welded.

It is desired to provide improved weld monitoring apparatus and improved methods of weld monitoring. -2 -

According to an aspect of the present invention, there is provided a weld monitoring apparatus comprising: a monitored current input configured to receive a monitored current signal from a welding system; integrator circuitry configured to integrate the monitored current signal or a representative signal derived therefrom over time to generate an integrated value; a user-operable scaling control configured to provide a scaling value set by a user; /0 scaling circuitry configured to scale the integrated value using the scaling value to generate a scaled integrated value; comparator circuitry configured to compare the scaled integrated value with one or more reference integrated values; and one or more indicators configured to indicate a result of the comparison of 15 the scaled integrated value with the one or more reference integrated values. Similarly, according to another aspect of the present invention, there is provided a method of weld monitoring using a weld monitoring apparatus, the method comprising the steps of: (i) receiving, via a monitored current input, a monitored current signal from 20 a welding system; (ii) integrating, using integrator circuitry, the monitored current signal or a representative signal derived therefrom over time to generate an integrated value; -3 - (iii) providing, via a user-operable scaling control, a scaling value set by a user (iv) scaling, using scaling circuitry, the integrated value using the scaling value to generate a scaled integrated value; (V) comparing, using comparator circuitry, the scaled integrated value with one or more reference integrated values; and (vi) indicating, via one or more indicators, a result of the comparison of the scaled integrated value with the one or more reference integrated values.

In other aspects, rather than integrating and then scaling to generate the 10 scaled integrated value, the apparatus may scale and then integrate to generate the scaled integrated value.

Thus, according to another aspect of the present invention, there is provided a weld monitoring apparatus comprising: a monitored current input configured to receive a monitored current signal 15 from a welding system; a user-operable scaling control configured to provide a scaling value set by a user; scaling circuitry configured to scale the monitored current signal or a representative signal derived therefrom using the scaling value to generate a scaled signal; integrator circuitry configured to integrate the scaled signal over time to generate a scaled integrated value; comparator circuitry configured to compare the scaled integrated value with one or more reference integrated values; and -4 -one or more indicators configured to indicate a result of the comparison of the scaled integrated value with the one or more reference integrated values.

Similarly, according to another aspect of the present invention, there is provided a method of weld monitoring using a weld monitoring apparatus, the method comprising the steps of: (i) receiving, via a monitored current input, a monitored current signal from a welding system; (ii) providing, via a user-operable scaling control, a scaling value set by a user; /0 (Hi) scaling, using scaling circuitry, the monitored current signal or a representative signal derived therefrom using the scaling value to generate a scaled signal; (iv) integrating, using integrator circuitry, the scaled signal over time to generate a scaled integrated value; /5 (v) comparing, using comparator circuitry, the scaled integrated value with one or more reference integrated values; and (vi) indicating, via one or more indicators, a result of the comparison of the scaled integrated value with the one or more reference integrated values.

As will be appreciated, the present invention provides a simple and effective way in which to monitor a welding process. In particular, when using the apparatus, the user merely needs to set the scaling value, perform the welding process, and monitor the one or more indicators. Furthermore, the present invention provides a simple and effective way in which to calibrate the apparatus based on executing an exemplary high-quality weld, which may be formed using -5 -the particular type of materials to be welded. In particular, using the apparatus may comprise performing one or more iterations of a calibration process, wherein the calibration process comprises: setting the scaling value using the user-operable scaling control; forming an exemplary weld; performing steps (i) to (vi) using the apparatus; and (if necessary) adjusting the scaling value using the user-operable scaling control based on the result indicated by the one or more indicators. Adjusting the scaling value may include increasing the scaling value when one or more indicators indicate that one or more reference integrated values have not been reached as a result of forming the exemplary weld and/or /0 decreasing the scaling value when one or more indicators indicate that one or more other reference integrated values have been reached as a result of forming the exemplary weld. Using the apparatus may then comprise setting or maintaining the scaling value as determined during calibration, forming a subsequent weld, and monitoring the one or more indicators. In this way, it can readily and consistently be determined whether the subsequent weld is likely to be comparable in quality with the exemplary weld(s) formed during calibration (e.g. in terms of energy delivered to the weld). The present invention can also avoid the need to perform frequent specialist calibration of the apparatus using known absolute voltages and currents, and can avoid the need for the user to have knowledge of the desired absolute values for high-quality welds, e.g. in SI units, such as amps, volts, joules and watts. The present invention can therefore provide simple, low-cost and effective weld monitoring.

In embodiments, the apparatus may further comprise current amplifying and/or filtering circuitry configured to receive the monitored current signal from -6 -the monitored current input and to output an amplified and/or filtered version of the monitored current signal. The current filtering circuitry may comprise a low pass current filter. Thus, the current filtering circuitry may attenuate frequencies in the monitored current signal which are above a selected cut-off frequency.

These embodiments can help to improve the accuracy and consistency of the apparatus In embodiments, the apparatus may further comprise multiplying circuitry, wherein the multiplying circuitry is configured to derive the representative signal using the (e.g. amplified and/or filtered) monitored current signal. In some /0 embodiments, the multiplying circuitry may be configured to derive the representative signal by squaring the (e.g. amplified and/or filtered) monitored current signal. This is because power is proportional to current squared, and energy is equal to the integral of power over time. In other embodiments, the apparatus may further comprise a monitored voltage input configured to receive a monitored voltage signal from a welding system, wherein the multiplying circuitry is configured to derive the representative signal by multiplying together the monitored voltage signal and the (e.g. amplified and/or filtered) monitored current signal. This is because power is equal to current multiplied by voltage, and energy is equal to the integral of power over time. In these other embodiments, the apparatus may further comprise voltage amplifying and/or filtering circuitry configured to receive the monitored voltage signal and output an amplified and/or filtered version of the monitored voltage signal for multiplying with the (e.g. amplified and/or filtered) monitored current signal. The voltage filtering circuitry may comprise a low pass voltage filter. Thus, the voltage filtering -7 -circuitry may attenuate frequencies in the monitored voltage signal which are above a selected cut-off frequency. Again, these embodiments can help to improve the accuracy and consistency of the apparatus.

Thus, in any of the embodiments described herein, the representative signal may be indicative of power delivered to a weld by the welding system (since power is proportional to current squared and is equal to current multiplied by voltage). Furthermore, the scaled integrated value may be indicative of energy delivered to a weld by the welding system (since energy is equal to the integral of power over time).

In embodiments, the apparatus may further comprise triggering circuitry configured to compare the monitored current signal or the representative signal derived therefrom with a trigger reference value, wherein the integrator circuitry is configured to start integrating when the triggering circuitry indicates that the monitored current signal or the representative signal derived therefrom is greater than the trigger reference value. The trigger reference value may be a fixed (e.g. current) value stored internally to the apparatus. The trigger reference value may be in the range 1% to 3% of the input range of the monitored current input. The input range of the monitored current input may be chosen based on the typical currents used for the type of welding that the apparatus is configured to monitor, e.g. arc welding and/or resistance welding. The integrator circuitry may be configured to start integrating when the triggering circuitry indicates that the monitored current signal or the representative signal derived therefrom is greater than the trigger reference value for a first pre-set period of time (so as to avoid triggering on irrelevant transient current). The integrator circuitry may be -8 -configured to stop integrating and/or reset when the triggering circuitry indicates that the monitored current signal or the representative signal derived therefrom is lower than a stop and/or reset reference value. The integrator circuitry may be configured to stop integrating and/or reset when the triggering circuitry indicates that the monitored current signal or the representative signal derived therefrom is lower than the stop and/or reset reference value for a second and/or third preset period of time (so as to avoid stopping and/or resetting due to irrelevant transient current). The stop and/or reset reference value may be a fixed (e.g. current) value stored internally to the apparatus. The trigger reference value may /0 be in the range 1% to 3% of the input range of the monitored current input. The stop and/or reset reference value may be, or may be the same as, the trigger reference value, or may be (slightly) lower than the trigger reference value to provide hysteresis. These embodiments can help to provide a highly representative integrated value based on the welding current and which is not affected by transient current.

In embodiments, the user-operable scaling control may comprise one or more rotary controls, slidable controls, buttons and/or switches. The user-operable scaling control may comprise a relatively finer scaling control configured to provide a relatively finer value set by a user and a relatively coarser scaling control configured to provide a relatively coarser value set by a user, the scaling value being a combination (e.g. addition) of the relatively coarser value and the relatively finer value. The relatively finer scaling control may provide relatively finer values in the range 0-0.9. The relatively coarser scaling control may provide relatively coarser values in the range 0-9. One or more relatively even finer -9 -controls and/or relatively even coarser controls may be provided as desired. For example, a relatively even coarser scaling control may provide relatively even coarser values in the range 0-90. The user-operable scaling control(s) may have discrete positions corresponding to discrete scaling values (e.g. in increments of 0.1, 1 or 10) or may have a continuous range of positions corresponding to a continuous range of scaling values. These embodiments can provide a simple and intuitive way for the user to set the scaling value, and to read and record that scaling value for use when monitoring subsequent welds. Furthermore, an appropriate range of scaling values can be found rapidly with the relatively /0 coarser control(s) and then the scaling value can be fine-tuned with the relatively finer control(s).

In embodiments, the apparatus may further comprise a user-operable tolerance control configured to provide one or more tolerance values set by a user, and reference modifier circuitry configured to modify a base reference integrated value using the one or more tolerance values to generate one or more modified reference integrated values to be compared with the scaled integrated value. The one or more tolerance values may correspond to a % increase or (Yo decrease in the base reference integrated value. The base reference integrated value may be a fixed value stored internally to the apparatus. The user-operable tolerance control may comprise one or more rotary controls, slidable controls, buttons and/or switches. The user-operable tolerance control may comprise a high-level tolerance control configured to provide a high-level tolerance value (e.g. % increase) set by a user, the reference modifier circuitry being configured to modify the base reference integrated value using the high-level tolerance value -10 -to generate a high-level reference integrated value to be compared with the scaled integrated value. For example, a high-level tolerance value corresponding to a 5% increase in the base reference integrated value may multiply the base reference integrated value by 1.05 to generate the high-level reference integrated value. The user-operable tolerance control may comprise a low-level tolerance control configured to provide a low-level tolerance value (e.g. % decrease) set by a user, the reference modifier circuitry being configured to modify the base reference integrated value using the low-level tolerance value to generate a low-level reference integrated value to be compared with the scaled integrated value.

For example, a low-level tolerance value corresponding to a 5% decrease in the base reference integrated value may multiply the base reference integrated value by 0.95 to generate the low-level reference integrated value. The user-operable tolerance control(s) may have discrete positions corresponding to discrete tolerance values or may have a continuous range of positions corresponding to a continuous range of tolerance values. These embodiments can provide a simple and intuitive way for the user to set acceptable tolerances to the base reference integrated value, and to read and record those tolerances for use when monitoring subsequent welds.

In embodiments, the one or more indicators may comprise one or more of: a base indicator configured to indicate that the scaled integrated value is greater than a base reference integrated value; a high-level indicator to indicate that the scaled integrated value is greater than a high-level reference integrated value; a low-level indicator to indicate that the scaled integrated value is less than a low-level reference integrated value; and a mid-level indicator to indicate that the -11 -scaled integrated value is between a high-level or base reference integrated value and a low-level reference integrated value or alternatively to indicate that the scaled integrated value is between a high-level reference integrated value and a low-level or base reference integrated value. The base indicator may be monitored during calibration, with the scaling value being set such that the scaled integrated value Oust) exceeds the base reference integrated value as a result of the exemplary weld(s). Alternatively or additionally, the mid-level indicator may be monitored during calibration, with the scaling value being set such that the scaled integrated value is between a high-level or base reference integrated value and a low-level reference integrated value or alternatively is between a high-level reference integrated value and a low-level or base reference integrated value as a result of the exemplary weld(s). The low-level indicator, high-level indicator and/or the mid-level indicator may be monitored during a subsequent weld to determine whether the subsequent weld is likely to be comparable in quality with the exemplary weld(s) formed during calibration. The one or more indicators may be visual (e.g. lights, such as LEDs) and/or audible (e.g. alarms).

In embodiments, the apparatus may further comprise a weld pulse indicator configured to indicate that the monitored current signal or the representative signal derived therefrom is greater than a trigger reference value.

The weld pulse indicator may be configured to indicate that the monitored current signal or the representative signal derived therefrom is greater than a stop and/or reset reference value. The weld pulse indicator can help to indicate that a welding process is being performed and/or that the weld monitoring apparatus is operational.

In embodiments, the apparatus may further comprise one or more outputs for outputting one or more signals or values derived by the apparatus. The one or more signals or values may comprise one or more of: the (e.g. amplified and/or filtered) monitored current signal, the (e.g. amplified and/or filtered) monitored voltage signal, the representative signal, the scaled representative signal, the integrated value, the scaled integrated value, and one or more values (e.g. logic levels) corresponding to the one or more indications provided by the one or more indicators. The one or more signals or values may be used for further analysis of the weld parameters and/or for automated processes, such as operation of weld rejection mechanisms (rejection chutes) in automated welding systems.

In embodiments, the apparatus may be a portable and/or bench-top apparatus. The apparatus may further comprise one or more leads for connecting the weld apparatus (e.g. the electrode cables of the weld apparatus for current monitoring and/or electrodes of the weld apparatus for voltage monitoring) to the one or more inputs. The apparatus may further comprise one or more leads for connecting the one or more outputs to external weld control and/or monitoring systems.

In embodiments, the various "circuitry" referred to herein may be of any desired and suitable form that is configured to perform the functions described herein The various "circuitry" referred to herein may comprise non-programmable or "hard-wired" circuitry and/or may comprise programmable circuitry as desired. The various "circuitry" referred to herein may comprise discrete electronic components (e.g. passive components, active components, etc.), electrical conductors (e.g. wiring, leads, tracks, vias, printed circuit boards (PCBs), etc.) and/or integrated electronic circuits (e.g. microchips, microprocessors, FPGAs, electronic memories, etc.) as desired.

By way of example only, embodiments of the invention will now be described in detail with reference being made to the accompanying drawings in 5 which: Figure 1A is a front view of a weld monitoring apparatus according to an embodiment of the present invention; Figure 1B is a top view of the weld monitoring apparatus of Figure 1A; Figure 2 is a block diagram of the main internal components of the weld /0 monitoring apparatus of Figure 1A according to an embodiment of the present invention; and Figure 3 is a block diagram of the main internal components of the weld monitoring apparatus of Figure 1A according to another embodiment of the present invention.

Figures 1A and 1B show a portable bench-top weld monitoring apparatus according to an embodiment of the present invention. The apparatus 100 comprises a user-operable scaling control 102 by which a user can set a scaling value. The scaling control 102 comprises a relatively finer scaling control 104 and a relatively coarser scaling control 106, each in the form of a rotary control having discrete positions 0-9 corresponding to discrete scaling values. The finer scaling control 104 provides a relatively finer value in increments of 0.1 in the range 00.9 and the coarser scaling control 106 provides a relatively coarser value in increments of 1 in the range 0-9. The scaling value is derived by addition of the relatively coarser value and the relatively finer value set by the user. In the example shown, the scaling value is 5.3 (i.e. 3x0.1 + 5x1). In other embodiments not illustrated, the scaling control can comprise an even coarser scaling control which provides a relatively even coarser value in increments of 10 in the range 0-90. The purpose of the scaling value is discussed in more detail below.

The apparatus 100 further comprises a user-operable tolerance control 108 by which a user can set tolerance values. The tolerance control 108 comprises a high-level tolerance control 110 and a low-level tolerance control 112, each in the form of a rotary control having discrete positions 1-10 corresponding to discrete tolerance values in the form of a % increase or cYa /0 decrease in a base reference integrated value. In the example shown, a high-level tolerance value corresponding to a 7% increase in the base reference integrated value is set by the high-level tolerance control 110, which provides a high-level reference integrated value of 1.07 times the base reference integrated value. Similarly, a low-level tolerance value corresponding to a 2% decrease in the base reference integrated value is set by the low-level tolerance control 112, which provides a low-level reference integrated value of 0.98 times the base reference integrated value. The purpose of the reference integrated values is discussed in more detail below.

The apparatus 100 further comprises a weld pulse indicator 114 in the form of an LED which indicates when a monitored current signal is greater than a trigger reference value, and thus that a weld is being formed. The apparatus 100 further comprises a base indicator 116, a high-level indicator 118 and a low-level indicator 120, each in the form of an LED, the purpose of which will be discussed in more detail below. The apparatus 100 further comprises a power -15 -indicator 122 in the form of an LED which indicates that the apparatus 100 is powered.

The apparatus 100 further comprises a monitored current input 124 that connects to a lead for receiving a monitored current signal from a welding system. 5 The apparatus 100 further comprises a monitored voltage input 126 that connects to a lead for receiving a monitored voltage signal from the welding system. The apparatus 100 further comprises a first output 128 for outputting an amplified/filtered version of the monitored current signal and a second output 130 for outputting logic levels derived by the apparatus 100. These outputted signals /0 and values can be subject to additional processing by an external weld control and/or monitoring system if desired. The apparatus 100 is powered via a 24V connector 132, although other voltage supplies could be used.

Referring now to Figures 2 and 3, which show alternative embodiments of the present invention, the weld monitoring apparatus 100 comprises current amplifying circuitry 202 and low pass current filtering circuitry 204 that receives a monitored current signal I from the monitored current input 124 and outputs an amplified and filtered version of the monitored current signal I. The weld monitoring apparatus 100 further comprises voltage amplifying circuitry 206 and low pass voltage filtering circuitry 208 that receives a monitored voltage signal V from the monitored voltage input 126 and outputs an amplified and filtered version of the monitored voltage signal V. The amplified/filtered monitored current signal may also be output via the first output 128 for further analysis if desired.

The weld monitoring apparatus 100 further comprises multiplying circuitry 210 that multiplies the monitored current signal I and the monitored voltage signal -16 -V together to generate a representative signal P indicative of power delivered to a weld by the welding system. In other embodiments, the voltage circuitry may be omitted/unused, and the multiplying circuitry may instead square the monitored current signal I to generate a representative signal P indicative of power delivered to a weld by the welding system.

In the embodiment of Figure 2, the representative signal P is integrated over time by integrator circuitry 212 to generate an integrated value E. The integrated value E is scaled by scaling circuitry 214 using the scaling value provided by the scaling control 102 to generate a scaled integrated value E. The scaled integrated value Es is indicative of energy delivered to the weld by the welding system.

Alternatively, in the embodiment of Figure 3, the representative signal P is scaled by scaling circuitry 214 using the scaling value provided by the scaling control 102 to generate a scaled representative signal P. The scaled representative signal Ps is integrated over time by integrator circuitry 212 to generate a scaled integrated value E. Again, the scaled integrated value Es is indicative of energy delivered to the weld by the welding system.

In either Figure 2 or Figure 3, the apparatus 100 further comprises triggering circuitry 216 that compares the monitored current signal I with a fixed trigger reference value IR stored in memory 218. The integrator circuitry 212 starts integrating when the triggering circuitry 216 indicates with a START signal that the monitored current signal is greater than the trigger reference value IR for a first period of time, which is indicative of the welding process commencing. Generally, the trigger reference value IR is in the range 1% to 3% of the input -17 -range of the monitored current input 124. In these embodiments, the trigger reference value IR is in the range 50-100 amps, but other trigger reference values could be used as desired. The integrator circuitry 212 stops integrating when the triggering circuitry indicates, via stop circuitry 220 and a STOP signal, that the monitored current signal is less than the trigger reference value IR for a second period of time, which is indicative of the welding process pausing temporarily. The integrator circuitry 212 also resets (e.g. zeros the integrated value) when the triggering circuitry indicates, via reset circuitry 222 and a RESET signal, that the monitored current signal is less than the trigger reference value IR for a third /0 period of time, which is longer than the second period of time and which is indicative of the weld having been completed.

The apparatus 100 further comprises comparator circuitry 224 that compares the scaled integrated value Es with a base reference integrated value ER stored in memory 226. The comparator circuitry 224 also compares the scaled integrated value ES with a high-level reference integrated value EH and a low-level reference integrated value EL provided by reference modifier circuitry 228. The reference modifier circuitry 228 modifies the base reference integrated value ER using the high-level and low-level tolerance values set by the tolerance control 108. In the example shown in Figure 1, the high-level reference integrated value EH is 1.07 x ER and the low-level reference integrated value EL is 0.98 x ER. The indicators 116, 118 and 120 indicate the respective results of the comparisons of the scaled integrated value Es with the reference integrated values EB, EH, and EL. Logic levels based on the respective results may also be output via the second output 130 for further analysis and weld control processes if desired.

As is shown in Figures 2 and 3, the weld monitoring apparatus 100 is used in conjunction with a welding system 300. The welding system 300 comprises a power supply 302 that delivers either a substantially fixed welding current or a substantially fixed welding voltage via electrode cables 304 to electrodes 306 5 during a welding process. To form the weld, the electrodes 306 are brought into contact with the parts 308 to be welded. The current which passes through the parts 308 generates significant heat in the region of the join to be made, which melts the parts 308. The region of the join is then allowed to cool so as to fuse the parts 308 together. A current shunt 310 is electrically coupled to one of the /0 electrode cables 304 to provide a monitored current signal Ito the apparatus 100 via the monitored current input 124, and voltage probes 312 are electrically coupled to the electrodes 306 to provide a monitored voltage signal V to the apparatus 100 via the monitored voltage input 126.

During initial set-up, using the apparatus 100 may comprise performing several iterations of a calibration process, in which the scaling value is set using the scaling control 102, an exemplary weld is formed using the welding system 300, and, if necessary, the scaling value is adjusted based on the results indicated by the indicators 116, 118 and 120, with the aim being for the scaled integrated value Es to just exceed the base reference integrated value EB as indicated by the base indicator 116, to be less than the high-level reference integrated value EH as indicated by the high-level indicator 118, and/or to be greater than the low-level reference integrated value EL as indicated by the low-level indicator 120. In some embodiments, one or more of the indicators may be supplemented or replaced by a mid-level indicator which indicates when the -19 -scaled integrated value Es is between the high-level reference integrated value EH and the low-level reference integrated value EL.

During subsequent welding, using the apparatus 100 comprises setting or maintaining the scaling value as determined during calibration, forming a subsequent weld using the welding system 300, and monitoring the indicators 116, 118, 120 to determine whether the subsequent weld is likely to be comparable in quality with the exemplary weld or welds formed during calibration, with the aim being for the weld to result in a scaled integrated value Es that is less than the high-level reference integrated value EH as indicated by the high-level indicator 118, and/or greater than the low-level reference integrated value EL as indicated by the low-level indicator 120. Again, in some embodiments, one or more of the indicators may be supplemented or replaced by a mid-level indicator which indicates when the scaled integrated value Es is between the high-level reference integrated value EH and the low-level reference integrated value EL.

Claims

-20 -CLAIMS1. A weld monitoring apparatus comprising: a monitored current input configured to receive a monitored current signal from a welding system; integrator circuitry configured to integrate the monitored current signal or a representative signal derived therefrom over time to generate an integrated value; a user-operable scaling control configured to provide a scaling value set by a user; /0 scaling circuitry configured to scale the integrated value using the scaling value to generate a scaled integrated value; comparator circuitry configured to compare the scaled integrated value with one or more reference integrated values; and one or more indicators configured to indicate a result of the comparison of 15 the scaled integrated value with the one or more reference integrated values.
2. A weld monitoring apparatus comprising: a monitored current input configured to receive a monitored current signal from a welding system; a user-operable scaling control configured to provide a scaling value set 20 by a user; scaling circuitry configured to scale the monitored current signal or a representative signal derived therefrom using the scaling value to generate a scaled signal; -21 -integrator circuitry configured to integrate the scaled signal over time to generate a scaled integrated value; comparator circuitry configured to compare the scaled integrated value with one or more reference integrated values; and one or more indicators configured to indicate a result of the comparison of the scaled integrated value with the one or more reference integrated values.
3. The apparatus as claimed in claim 1 or 2, further comprising current amplifying and/or filtering circuitry configured to receive the monitored current signal from the monitored current input and to output an amplified and/or filtered /0 version of the monitored current signal.
4. The apparatus as claimed in claim 1, 2 or 3, further comprising multiplying circuitry, wherein the multiplying circuitry is configured to derive the representative signal using the monitored current signal.
5. The apparatus as claimed in claim 4, wherein the multiplying circuitry is configured to derive the representative signal by squaring the monitored current signal.
6. The apparatus as claimed in claim 4, further comprising a monitored voltage input configured to receive a monitored voltage signal from a welding system, wherein the multiplying circuitry is configured to derive the representative signal by multiplying together the monitored voltage signal and the monitored current signal.
7. The apparatus as claimed in claim 6, further comprising voltage amplifying and/or filtering circuitry configured to receive the monitored voltage signal and -22 -output an amplified and/or filtered version of the monitored voltage signal for multiplying with the monitored current signal.
8. The apparatus as claimed in any one of the preceding claims, wherein the representative signal is indicative of power delivered to a weld by the welding 5 system.
9. The apparatus as claimed in any one of the preceding claims, wherein the scaled integrated value is indicative of energy delivered to a weld by the welding system.
10. The apparatus as claimed in any one of the preceding claims, further /0 comprising triggering circuitry configured to compare the monitored current signal or the representative signal derived therefrom with a trigger reference value, wherein the integrator circuitry is configured to start integrating when the triggering circuitry indicates that the monitored current signal or the representative signal derived therefrom is greater than the trigger reference value.
11. The apparatus as claimed in claim 10, wherein the integrator circuitry is configured to start integrating when the triggering circuitry indicates that the monitored current signal or the representative signal derived therefrom is greater than the trigger reference value for a first pre-set period of time.
12. The apparatus as claimed in claim 10 or 11, wherein the integrator circuitry is configured to stop integrating and/or reset when the triggering circuitry indicates that the monitored current signal or the representative signal derived therefrom is lower than a stop and/or reset reference value.
-23 - 13. The apparatus as claimed in claim 12, wherein the integrator circuitry is configured to stop integrating and/or reset when the triggering circuitry indicates that the monitored current signal or the representative signal derived therefrom is lower than the stop and/or reset reference value for a second and/or third pre-set period of time.
14. The apparatus as claimed in any one of the preceding claims, wherein the user-operable scaling control comprises one or more rotary controls, slidable controls, buttons and/or switches.
15. The apparatus as claimed in any one of the preceding claims, wherein the /0 user-operable scaling control comprises a relatively coarser scaling control configured to provide a relatively coarser value set by a user and a relatively finer scaling control configured to provide a relatively finer value set by a user, the scaling value being a combination of the relatively coarser value and the relatively finer value.
16. The apparatus as claimed in any one of the preceding claims, further comprising a user-operable tolerance control configured to provide one or more tolerance values set by a user, and reference modifier circuitry configured to modify a base reference integrated value using the one or more tolerance values to generate one or more modified reference integrated values to be compared with the scaled integrated value.
17. The apparatus as claimed in claim 16, wherein the user-operable tolerance control comprises one or more rotary controls, slidable controls, buttons and/or switches.
-24 - 18. The apparatus as claimed in claim 16 or 17, wherein the user-operable tolerance control comprises a high-level tolerance control configured to provide a high-level tolerance value set by a user, the reference modifier circuitry being configured to modify the base reference integrated value using the high-level tolerance value to generate a high-level reference integrated value to be compared with the scaled integrated value.
19. The apparatus as claimed in claim 16, 17 or 18, wherein the user-operable tolerance control comprises a low-level tolerance control configured to provide a low-level tolerance value set by a user, the reference modifier circuitry being configured to modify the base reference integrated value using the low-level tolerance value to generate a low-level reference integrated value to be compared with the scaled integrated value.
20. The apparatus as claimed in any one of the preceding claims, wherein the one or more indicators comprise one or more of: a base reference indicator configured to indicate that the scaled integrated value is greater than a base reference integrated value; a high-level indicator to indicate that the scaled integrated value is greater than a high-level reference integrated value; a low-level indicator to indicate that the scaled integrated value is less than a low-level reference integrated value; and a mid-level indicator to indicate that the scaled integrated value is between a high-level or base reference integrated value and a low-level reference integrated value or alternatively to indicate that the scaled integrated value is between a high-level reference integrated value and a low-level or base reference integrated value.-25 -
21. The apparatus as claimed in any one of the preceding claims, further comprising one or more outputs for outputting one or more signals or values derived by the apparatus
22. The apparatus as claimed in any one of the preceding claims, wherein the apparatus is a portable and/or bench-top apparatus.
23. A method of weld monitoring using a weld monitoring apparatus, the method comprising the steps of: (i) receiving, via a monitored current input, a monitored current signal from a welding system; 00 integrating, using integrator circuitry, the monitored current signal or a representative signal derived therefrom over time to generate an integrated value; (Hi) providing, via a user-operable scaling control, a scaling value set by a user; (iv) scaling, using scaling circuitry, the integrated value using the scaling value to generate a scaled integrated value; (v) comparing, using comparator circuitry, the scaled integrated value with one or more reference integrated values; and (vi) indicating, via one or more indicators, a result of the comparison of the 20 scaled integrated value with the one or more reference integrated values.
24 A method of weld monitoring using a weld monitoring apparatus, the method comprising the steps of: (i) receiving, via a monitored current input, a monitored current signal from a welding system; -26 - (ii) providing, via a user-operable scaling control, a scaling value set by a user (Hi) scaling, using scaling circuitry, the monitored current signal or a representative signal derived therefrom using the scaling value to generate a scaled signal; (iv) integrating, using integrator circuitry, the scaled signal over time to generate a scaled integrated value; (v) comparing, using comparator circuitry, the scaled integrated value with one or more reference integrated values; and /0 (vi) indicating, via one or more indicators, a result of the comparison of the scaled integrated value with the one or more reference integrated values.
25. A method as claimed in claim 23 or 24, comprising performing one or more iterations of a calibration process, wherein the calibration process comprises: setting the scaling value using the user-operable scaling control; forming an exemplary weld; performing steps (i) to (vi); and if necessary, adjusting the scaling value using the user-operable scaling control based on the result indicated by the one or more indicators.