Difference between revisions of "NVGate Tachometer"

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NVGate Tachometer (view source)

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NVGate can set up several tachometer sources, including virtual tachometers in the case of multiple shafts. Tachometers are based on signals that provide pulses/revolution or from a CAN bus or from a voltage proportional to the angular velocity.
NVGate can set up several tachometer sources, including virtual tachometers in the case of multiple shafts. Tachometers are based on signals that provide pulses/revolution from a CAN bus or from a voltage proportional to the angular velocity.


==Connect==
==Connect==
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! Using GoToResult !! Using Ribbon ASB
! Using GoToResult !! Using Ribbon ASB
|-
|-
| On this window, only input tachometer and ext. synch tachometer are available. To use it, just open the GoToResults windows, then select the tachometer. [[File:tach3.png|framed|none]]  ||  For more advanced option, on ribbon/acquisition tab, the left button (''Select'') allows dispatching the different tachometer type to the plug-in analyzers. The others items open the corresponding event detection setup.[[File:tach1.png|framed|none]] ''Select:'' '' Shows the list of available tachometer sources and allows plugging it, to the plug-in, events and waterfall.
| On this window, only input tachometer and ext. synch tachometers are available. To use it, just open the GoToResults windows, then select the tachometer. [[File:tach3.png|framed|none]]  ||  For more advanced options, on ribbon/acquisition tab, the left button (''Select'') allows dispatching the different tachometer type to the plug-in analyzers. The others items open the corresponding event detection setup.[[File:tach1.png|framed|none]] ''Select:'' '' Shows the list of available tachometer sources and allows plugging it, to the plug-in, events and waterfall.
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All tach can be used as source for the RPM and Delta RPM event type and/or for order analysis (Constant band tracking of the FFT plug-in and Synchronous Order Analysis plug-in analyzers), and/or as a reference for the waterfall plug-in.
All tachs can be used as a source for the RPM and Delta RPM event type and/or for order analysis (Constant band tracking of the FFT plug-in and Synchronous Order Analysis plug-in analyzers), and/or as a reference for the waterfall plug-in.


'''Display'''
'''Display'''
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! Using GoToResult !! Using Add/remove windows
! Using GoToResult !! Using Add/remove windows
|-
|-
|  You can display scalar value, or profile using GoToResult windows.[[File:tach5.png|600px|none]] First activate a tachometer in a window plug in. Second, A new tab is create : "tachometer". select the profile or scalar value  || For advanced results, use the: add/remove windows.
|  You can display scalar values, or profiles using GoToResult windows.[[File:tach5.png|600px|none]] First activate a tachometer in a window plug in. Second, a new tab is created: "tachometer". Select the profile or scalar value  || For advanced results, use the: add/remove windows.
[[File:tach6.png|600px|none]]
[[File:tach6.png|600px|none]]
Tips : to create Advanced tachometer profile, put the scalar of tachometer into the [[NVGate_Waterfall|waterfall]]
Tips : to create Advanced tachometer profile, put the scalar of tachometer into the [[NVGate_Waterfall|waterfall]]
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==Tachometer Source==
==Tachometer Source==


On NVGate we can set up several tachometer sources, including virtual tachometers in the case of multiple shafts. Tachometers are based on signals that provide pulses/revolution or from a CAN bus or from a voltage proportional to the angular velocity.
In NVGate we can set up several tachometer sources, including virtual tachometers in the case of multiple shafts. Tachometers are based on signals that provide pulses/revolution from a CAN bus or from a voltage proportional to the angular velocity.
[[File:tach4.png|framed|none]]
[[File:tach4.png|framed|none]]


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===Input: Tachs===
===Input: Tachs===


[[Image:Reports_Tools_Ribbons_354.png]]''Inputs:'' Opens the properties dialog for the tachometers based on a dynamic input
[[Image:Reports_Tools_Ribbons_354.png]]''Inputs:'' Opens the properties dialog for the tachometers based on a dynamic input.
Used to define up to 4 tachometers using signal from fast analog input (from the Front-end or from the Player).
Used to define up to 4 tachometers using signal from fast analog inputs (from the Front-end or from the Player).


* '''Source:''': the tach input signal (NONE by default). The input signal can be any Front-end input in Connected mode on line or any Player track in Post-analysis mode (except for the DC input and the Ext. Sync. inputs or tracks). (note : on OR35V1, Input 5 to input 8 are not able to be set as source using an OR35 analyzer.)
* '''Source:''': the tach input signal (NONE by default). The input signal can be any Front-end input in Connected mode, on-line or any Player track in Post-analysis mode (except for the DC input and the Ext. Sync. inputs or tracks). (note : on OR35V1, Input 5 to input 8 are not able to be set as source using an OR35 analyzer.)
* '''Input filter''': adds a digital filter before the tach process. The user can choose any filter from the list of the defined filters.
* '''Input filter''': adds a digital filter before the tach process. The user can choose any filter from the list of the defined filters.


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* '''Average size''': defines the average number used to compute the average speed. Revolution number n average speed is: avrg_speed<nowiki>[</nowiki>n-1<nowiki>]</nowiki> <nowiki>+</nowiki> (inst_speed<nowiki>[</nowiki>n-1<nowiki>]</nowiki> - avrg_speed<nowiki>[</nowiki>n-1<nowiki>]</nowiki>) / avrg_size.
* '''Average size''': defines the average number used to compute the average speed. Revolution number n average speed is: avrg_speed<nowiki>[</nowiki>n-1<nowiki>]</nowiki> <nowiki>+</nowiki> (inst_speed<nowiki>[</nowiki>n-1<nowiki>]</nowiki> - avrg_speed<nowiki>[</nowiki>n-1<nowiki>]</nowiki>) / avrg_size.
* '''Max speed''': predefine a maximum angular speed to preset the scale and order tracking maxima. The limit of Max speed depends on the sampling frequency of the input signal and is equal to: 60 * Fe / (2 * 2.56) for the maximum. The Max speed setting is also used:
* '''Max speed''': predefines a maximum angular speed to preset the scale and order tracking maxima. The limit of Max speed depends on the sampling frequency of the input signal and is equal to: 60 * Fe / (2 * 2.56) for the maximum. The Max speed setting is also used:
* to specify the limit of Y axis of the RPM profile result
* to specify the limit of Y axis of the RPM profile result
* to compute the limit of the maximum order of the SOA plug-in analyzer.
* to compute the limit of the maximum order of the SOA plug-in analyzer.
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[[Image:Reports_Tools_Ribbons_355.png]]:  ''Ext. Synch:''Opens the properties dialog for the tachometers based on a high speed oversampled Ext Synch input.<big>Big text</big>
[[Image:Reports_Tools_Ribbons_355.png]]:  ''Ext. Synch:''Opens the properties dialog for the tachometers based on a high speed oversampled Ext Synch input.<big>Big text</big>
In acquisition mode, the tach Ext synch come frome the frond end.<br>
In acquisition mode, the tach Ext synch comes from the frond end.<br>


In post analyse, we connect player track on tachometer Ext synch ressource.<br>
In post analyze, we connect player track on tachometer Ext synch resource.<br>




====Acquisition mode====
====Acquisition mode====
Externals syncs are high speed levels comparator that provides accurate events date for the tachs and trigger. External sync is sampled at 64 time the Front-end sampling frequency in order to achieve higher precision in delay or phase measurements.
External syncs are high speed level comparators that provides accurate events dates for the tachs and trigger. External sync is sampled at 64 time the Front-end sampling frequency in order to achieve higher precision in delay or phase measurements.


For external sync or tach signals whose frequencies overload the inputs sampling rate, an internal hardware divider is available in order to lower signal frequency. The upper frequency of the external sync must be lower than 64 times the Front-end frequency range. At input frequencies greater than 300 kHz, sensitivity can be decreased due to the electronic circuitry.
For external sync or tach signals whose frequencies overload the inputs sampling rate, an internal hardware divider is available in order to lower signal frequency. The upper frequency of the external sync must be lower than 64 times the Front-end frequency range. At input frequencies greater than 300 kHz, sensitivity can be decreased due to the electronic circuitry.
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* If Slope is set to RISE, the input signal must go below Threshold - Hystersis before a new pulse can be detected.
* If Slope is set to RISE, the input signal must go below Threshold - Hystersis before a new pulse can be detected.
* If Slope is set to FALL, the input signal must go above Threshold <nowiki>+</nowiki> Hystersis before a new pulse can be detected. This setting is used to reject false pulse detection following, for example, a transition of the input signal. This setting can be displayed in dB.
* If Slope is set to FALL, the input signal must go above Threshold <nowiki>+</nowiki> Hystersis before a new pulse can be detected. This setting is used to reject false pulse detection following, for example, a transition of the input signal. This setting can be displayed in dB.
* '''Pre-''''''divider''': Hardware pre-divider is available after the edge detector and is used to reduce the frequency of the signal to be measured. When the tach is enabled, the measured speed take into account the pre-divider setting when displaying the true RPM value. The user can enter any integer value between 1 and 255. If tach is <nowiki>’</nowiki>On<nowiki>’</nowiki> this setting is linked to the <nowiki>’</nowiki>pulse/rev<nowiki>’</nowiki> setting.
* '''Pre-''''''divider''': Hardware pre-divider is available after the edge detector and is used to reduce the frequency of the signal to be measured. When the tach is enabled, the measured speed takes into account the pre-divider setting when displaying the true RPM value. The user can enter any integer value between 1 and 255. If tach is <nowiki>’</nowiki>On<nowiki>’</nowiki> this setting it is linked to the <nowiki>’</nowiki>pulse/rev<nowiki>’</nowiki> setting.
* '''Post''''''-mutiplier:''' selection of the multiplier factor. It allows to generate an <nowiki>’</nowiki>ExtSync<nowiki>’</nowiki> signal which the pulse frequency is multiplied by the selected factor. The user can enter any integer value between 1 and 50. This is particularly used with slow time base as GPS or standard clock.
* '''Post''''''-mutiplier:''' selection of the multiplier factor. It allows the generation of a <nowiki>’</nowiki>ExtSync<nowiki>’</nowiki> signal which the pulse frequency is multiplied by the selected factor. The user can enter any integer value between 1 and 50. This is particularly useful with slow time base as GPS or standard clock.


[[Image:front_end_15.png|framed|none]]
[[Image:front_end_15.png|framed|none]]


* '''Multiplier Hold off: '''defines the maximum time (expressed in percentage of the last period measured after multiplication) between a detected pulse and a simulated pulse. If a simulated pulse is detected before this time has expired since the detected pulse then this pulse is not added. By this way, the simulated signal is synchronize with the input signal. The user can enter any value between 1% and 99%.
* '''Multiplier Hold off: '''defines the maximum time (expressed in percentage of the last period measured after multiplication) between a detected pulse and a simulated pulse. If a simulated pulse is detected before time has expired since the detected pulse then this pulse will not be added. In this way, the simulated signal is synchronized with the input signal. The user can enter any value between 1% and 99%.


[[Image:front_end_16.png|framed|none]]
[[Image:front_end_16.png|framed|none]]
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* '''Mode: '''This setting allows selecting available signal generated by the Ext. synch input to be used by the NVGate analysis components.
* '''Mode: '''This setting allows selecting available signals generated by the Ext. synch input to be used by the NVGate analysis components.




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|-
|-
|[[NVGate_Torsional|Torsional]]
|[[NVGate_Torsional|Torsional]]
|The input generates the instantaneous velocity measured with the F. to V converter from a pulses train. The torsional signal is considered as a dynamic input. It appears as Tors # in the inputs list (# being the Ext sync number)
|The input generates the instantaneous velocity measured with the F to V converter from a pulses train. The torsional signal is considered as a dynamic input. It appears as Tors # in the inputs list (# being the Ext sync number)


|-
|-
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|-
|-
|[[NVGate_Torsional#Angular_sampling_for_SOA_analysis|Sampling]]
|[[NVGate_Torsional#Angular_sampling_for_SOA_analysis|Sampling]]
|The detected pulses on the inputs will be used to synchronize the SOA re-sampling algorithm. The number of pulse/rev is f free and may be different from the SAO resolution.
|The detected pulses on the inputs will be used to synchronize the SOA re-sampling algorithm. The number of pulse/rev is free and may be different from the SAO resolution.


|-
|-
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* '''Hold off (% period): '''defines the minimum time (expressed in % of the last valid tach period) between 2 tach pulses used to measure RPM.
* '''Hold off (% period): '''defines the minimum time (expressed in % of the last valid tach period) between 2 tach pulses used to measure RPM.
If a pulse is detected before this time has expired since the last valid pulse then the new pulse is rejected. This is used to reject angular speed variations that are too large. This minimum time is in fact the maximum between the Hold off setting value and the value computed using the last tach period length and the Hold off (% period) setting value.
If a pulse is detected before the time has expired since the last valid pulse then the new pulse will be rejected. This is used to reject angular speed variations that are too large. This minimum time is in fact the maximum between the Hold off setting value and the value computed using the last tach period length and the Hold off (% period) setting value.


''Hidden/fixed: ''Hidden if Mode is Trigger or Torsional.
''Hidden/fixed: ''Hidden if Mode is Trigger or Torsional.
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The Max speed setting is also used:
The Max speed setting is also used:


* to specify the limit of Y axis of the RPM profile result
* to specify the limit of Y axis of the RPM profile result.
* to compute the limit of the maximum order of the SOA plug-in analyzer.
* to compute the limit of the maximum order of the SOA plug-in analyzer.
''Hidden/fixed: ''Hidden if Mode is Trigger.
''Hidden/fixed: ''Hidden if Mode is Trigger.
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* '''Hold off''': defines the minimum time (expressed in seconds) between two tach pulses used to measure angular speed. If a pulse is detected before this time has expired since the last valid pulse then the new pulse is rejected. This minimum time is in fact the maximum between the Hold off setting value and the value computed using the last tach period length and the Hold off  (% period) setting value. The user can enter any value between 0 and 36000s.
* '''Hold off''': defines the minimum time (expressed in seconds) between two tach pulses used to measure angular speed. If a pulse is detected before the time has expired since the last valid pulse then the new pulse will be rejected. This minimum time is in fact the maximum between the Hold off setting value and the value computed using the last tach period length and the Hold off  (% period) setting value. The user can enter any value between 0 and 36000s.
* '''Hold off (% period): '''defines the minimum time (expressed in % of the last valid tach period) between two tach pulses used to measure angular speed. If a pulse is detected before this time has expired since the last valid pulse then the new pulse is rejected. This is used to reject angular speed variations that are too large. This minimum time is in fact the maximum between the Hold off setting value and the value computed using the last tach period length and the Hold off (% period) setting value.
* '''Hold off (% period): '''defines the minimum time (expressed in % of the last valid tach period) between two tach pulses used to measure angular speed. If a pulse is detected before this time has expired since the last valid pulse then the new pulse is rejected. This is used to reject angular speed variations that are too large. This minimum time is in fact the maximum between the Hold off setting value and the value computed using the last tach period length and the Hold off (% period) setting value.


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===DC Tach===
===DC Tach===
Up to 4 tachometers using signal from DC inputs can be activated. It<nowiki>’</nowiki>s particularly interesting if a tachometric transducer which delivers voltage proportional to rotational speed is used for the measurement (the sensitivity is in Volt/RPM). The actual speed is continuously known during the rotation. Be aware than phase measurement is not accurate with the method.
Up to 4 tachometers using signal from DC inputs can be activated. It<nowiki>’</nowiki>s particularly interesting if a tachometric transducer which delivers voltage proportional to rotational speed is used for the measurement (the sensitivity is in Volt/RPM). The actual speed is continuously known during the rotation. Be aware that phase measurements are not accurate with the method.


====Acquisition====
====Acquisition====
[[image:DC_tach acquisition.png|framed|DC tach on connected mode]]
[[image:DC_tach acquisition.png|framed|DC tach on connected mode]]
On acquisition mode, you need to activate a DC input on the frond tend, then activate the tach option
On acquisition mode, you need to activate a DC input on the frond tend, then activate the tach option.


'''Tach:''' On / Off. Used to activate a tachometer with an RPM level proportional to the DC level
'''Tach:''' On / Off. Used to activate a tachometer with an RPM level proportional to the DC level.
Rotation: Depending on the way you look at a measured shaft or on the convention you are using, the shaft may be considered as rotating clock wise or counter clock wise. This has noticeable impact on the phase of spectra and orders.
Rotation: Depending on the way you look at a measured shaft or on the convention you are using, the shaft may be considered as rotating clock wise or counter clock wise. This has noticeable impact on the phase of spectra and orders.


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'''Average size:''' defines the average number used to compute the average speed. Revolution number n average speed is: avrg_speed[n-1] + (inst_speed[n-1] - avrg_speed[n-1]) / avrg_size.
'''Average size:''' defines the average number used to compute the average speed. Revolution number n average speed is: avrg_speed[n-1] + (inst_speed[n-1] - avrg_speed[n-1]) / avrg_size.


'''Max speed:''' defines the highest measured angular speed. speed higher than Max speed are rejected. By default Max speed is expressed in RPM.
'''Max speed:''' defines the highest measured angular speed. Speeds higher than Max speed are rejected. By default Max speed is expressed in RPM.


The Max speed setting is also used:
The Max speed setting is also used:


* to specify the limit of Y axis of the RPM profile result
* To specify the limit of Y axis of the RPM profile result.
* to compute the limit of the maximum order of the SOA plug-in analyzer.
* To compute the limit of the maximum order of the SOA plug-in analyzer.
'''Min speed''': defines the lowest measured angular speed. All revolutions with a speed lower than Min speed are forced to 0 RPM. By default Min speed is expressed in RPM. Min speed is automatically adjusted to Max speed/1000 but it is possible to go lower.
'''Min speed''': defines the lowest measured angular speed. All revolutions with a speed lower than Min speed are forced to 0 RPM. By default Min speed is expressed in RPM. Min speed is automatically adjusted to Max speed/1000 but it is possible to go lower.
* '''Rotation:''' This setting defines the way the phase variation is counted: clockwise or counter-clockwise for each tachometer.
* '''Rotation:''' This setting defines the way the phase variation is counted: clockwise or counter-clockwise for each tachometer.
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In Post-Analyze, the DC tachs are available.
In Post-Analyze, the DC tachs are available.


They can be activated and connected to a DC Input available in the signal loaded in the player.  The set up magnitude, sensitivity and offset allow to calibrate the DC Input in post analyze to obtain the correct values of the angular velocity.
They can be activated and connected to a DC Input available in the signal loaded in the player.  Then set up magnitude, sensitivity and offset allow to calibrate the DC Input in post analyze to obtain the correct values of the angular velocity.
Settings are the same than in acquisition mode
Settings are the same in acquisition mode.


=====Extract a DC tachometer from dynamical input=====
=====Extract a DC tachometer from dynamical input=====
On post analysis, if you have record a tachometer on a dynamical input, you can extract the DC of this channels using the monitor, Then, define a DC tachomter with the value "monitor DC". The process is as follow :
On post analysis, if you have record a tachometer on a dynamical input, you can extract the DC of this channels using the monitor. Then, define a DC tachometer with the value "monitor DC". The process is as follow :


* Open the ribbon Analyses / Monitor / Inputs button.
* Open the ribbon Analyses / Monitor / Inputs button.
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[[Image:Reports_Tools_Ribbons_356.png]]:  ''Fractional:'' '' Opens the properties dialog for the tachometers that derives from another one. Fractional tach. computes RPM speed for a non accessible shaft by using gear ratio setting.'' ''Adapted for gear boxes and transmissions.
[[Image:Reports_Tools_Ribbons_356.png]]:  ''Fractional:'' '' Opens the properties dialog for the tachometers that derives from another one. Fractional tach. computes RPM speed for a non accessible shaft by using gear ratio setting.'' ''Adapted for gear boxes and transmissions.
Note: the fractional tach. cannot be settled from the ''Vision'' interface, use the ASB for it.
Note: the fractional tach. cannot be settled from the ''Vision'' interface, use the ASB for it.
Used to define up to 4 fractional tach, using data from the tach or the Ext Tach.
Used to define up to 4 fractional tachs using data from the tach or the Ext Tach.


Virtual tach computes RPM speed for a not accessible shaft by using gear ratio setting.
Virtual tachs computes RPM speed for a not accessible shaft by using gear ratio setting.


[[Image:Tachometer_08.png|framed|none]]
[[Image:Tachometer_08.png|framed|none]]
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====Application====
====Application====
The main application is in automtive : studying vibration due to a CVT gear box. We will first compute the speed of the belt with a [https://en.wikipedia.org/wiki/Continuously_variable_transmission continuously variable transmission (CVT)]deducing by the speed of the 2 shafts. Then, with this belt speed, we can deduce vibration due to this belt using waterfall or order traking technics.
The main application is in automotive : studying vibration due to a CVT gear box. We will first compute the speed of the belt with a [https://en.wikipedia.org/wiki/Continuously_variable_transmission continuously variable transmission (CVT)]deducing by the speed of the 2 shafts. Then, with this belt speed, we can deduce vibration due to this belt using waterfall or order tracking techniques.
[[File:CVT1.png|framed|none]]
[[File:CVT1.png|framed|none]]
Exemple of study in CVT Vibration : https://www.hindawi.com/journals/sv/2015/857978/
Exemple of study in CVT Vibration : https://www.hindawi.com/journals/sv/2015/857978/


====How to use====
====How to use====
This module allows computing tachometer information (Speed, Phase) relatively to 2 measured tachometers. Up to 4 different combined tach can be computed simultaneously. The combined tach can be used as any other standard tach.
This module allows computing tachometer information (Speed, Phase) relatively to 2 measured tachometers. Up to 4 different combined tachs can be computed simultaneously. The combined tach can be used as any other standard tach.


* '''Label''': the name of the output tach.
* '''Label''': the name of the output tach.
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* '''Average size''': defines the average number used to compute the average speed. Revolution number n average speed is: avrg_speed<nowiki>[</nowiki>n-1<nowiki>]</nowiki> <nowiki>+</nowiki> (inst_speed<nowiki>[</nowiki>n-1<nowiki>]</nowiki> - avrg_speed<nowiki>[</nowiki>n-1<nowiki>]</nowiki>) / avrg_size.
* '''Average size''': defines the average number used to compute the average speed. Revolution number n average speed is: avrg_speed<nowiki>[</nowiki>n-1<nowiki>]</nowiki> <nowiki>+</nowiki> (inst_speed<nowiki>[</nowiki>n-1<nowiki>]</nowiki> - avrg_speed<nowiki>[</nowiki>n-1<nowiki>]</nowiki>) / avrg_size.
* '''Max speed''': predefine a maximum angular speed to preset the scale and order tracking maxima. The limit of Max speed depends on the sampling frequency of the input signal and is equal to: 60 * Fe / (2 * 2.56) for the maximum. The Max speed setting is also used:
* '''Max speed''': predefines a maximum angular speed to preset the scale and order tracking maxima. The limit of Max speed depends on the sampling frequency of the input signal and is equal to: 60 * Fe / (2 * 2.56) for the maximum. The Max speed setting is also used:
* to specify the limit of Y axis of the RPM profile result
* to specify the limit of Y axis of the RPM profile result
* to compute the limit of the maximum order of the SOA plug-in analyzer.
* to compute the limit of the maximum order of the SOA plug-in analyzer.
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Constants and parameters can be defined (except ''pi'' and ''e'') using the = sign; eg: ''var1 = pi * 2'' or ''var2 = rpm1/2''. The constants may be defined once only.
Constants and parameters can be defined (except ''pi'' and ''e'') using the = sign; eg: ''var1 = pi * 2'' or ''var2 = rpm1/2''. The constants may be defined only once.


Parameter/constant names must start with a letter and may be ended by a number.
Parameter/constant names must start with a letter and may be ended by a number.
LDesmet
maintenancecenter, writer
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