NVGate SOA and CBT techniques - Revision history

Lmagimel at 09:02, 26 November 2024

2024-11-26T09:02:07Z

← Older revision		Revision as of 11:02, 26 November 2024
Line 1:		Line 1:
			[[category:WikiOros]]
	This article compares Synchronous Order Analysis (SOA) method to the Constant Band Tracking (CBT) method.		This article compares Synchronous Order Analysis (SOA) method to the Constant Band Tracking (CBT) method.
	==Applications==		==Applications==

LDesmet: Adding Order Extraction video

2021-02-15T19:48:13Z

Adding Order Extraction video

← Older revision		Revision as of 21:48, 15 February 2021
Line 17:		Line 17:

	* For investigation. When people don<nowiki>'</nowiki>t know precisely what they are looking for (which order or frequency band to follow). The FFT waterfall can be used as a first step evaluation before using eventually SOA or CBT for in-depth analysis.		* For investigation. When people don<nowiki>'</nowiki>t know precisely what they are looking for (which order or frequency band to follow). The FFT waterfall can be used as a first step evaluation before using eventually SOA or CBT for in-depth analysis.

			<Youtube>https://www.youtube.com/watch?v=fdS2amoQ01I</Youtube>

	==Principles==		==Principles==

LDesmet: English edits

2020-06-12T20:30:41Z

English edits

Lmagimel: /* Principles */

2020-04-29T12:40:15Z

Principles

← Older revision		Revision as of 14:40, 29 April 2020
Line 23:		Line 23:

	It is an order analysis method for which the sampling is synchronous with the rotating speed measured from the tachometer. Re-sampling filters are used on the raw signal to give constant angle sampling and a triggered blocks size independent from the rotating speed (the size corresponds to a fixed number of revolutions).<br>		It is an order analysis method for which the sampling is synchronous with the rotating speed measured from the tachometer. Re-sampling filters are used on the raw signal to give constant angle sampling and a triggered blocks size independent from the rotating speed (the size corresponds to a fixed number of revolutions).<br>


	[[NVGate_Synchronous_Order_Analysis\|See SOA page for more info]].		[[NVGate_Synchronous_Order_Analysis\|See SOA page for more info]].

Lmagimel: /* SOA */

2020-04-29T12:40:06Z

SOA

← Older revision		Revision as of 14:40, 29 April 2020
Line 22:		Line 22:
	===SOA===		===SOA===

	It is an order analysis method for which the sampling is synchronous with the rotating speed measured from the tachometer. Re-sampling filters are used on the raw signal to give constant angle sampling and a triggered blocks size independent from the rotating speed (the size corresponds to a fixed number of revolutions).		It is an order analysis method for which the sampling is synchronous with the rotating speed measured from the tachometer. Re-sampling filters are used on the raw signal to give constant angle sampling and a triggered blocks size independent from the rotating speed (the size corresponds to a fixed number of revolutions).<br>


			[[NVGate_Synchronous_Order_Analysis\|See SOA page for more info]].

	===CBT===		===CBT===

Lmagimel: /* CBT */

2020-04-29T12:39:10Z

CBT

← Older revision		Revision as of 14:39, 29 April 2020
Line 26:		Line 26:
	===CBT===		===CBT===

	Constant Band Tracking consists in order analysis calculation based on energy summation from FFT data. Since the FFT module is used when tracking orders with the CBT feature, the trigger block duration is constant and no re-sampling is performed there. As a result, the number of rotation contained in one block depends on the rotating speed.		Constant Band Tracking consists in order analysis calculation based on energy summation from FFT data. Since the FFT module is used when tracking orders with the CBT feature, the trigger block duration is constant and no re-sampling is performed there. As a result, the number of rotation contained in one block depends on the rotating speed.<br>

	[[NVGate_CBT_principle_and_settings\|See CBT page for more info.]]		[[NVGate_CBT_principle_and_settings\|See CBT page for more info.]]

Lmagimel: /* CBT */

2020-04-29T12:39:00Z

CBT

← Older revision		Revision as of 14:39, 29 April 2020
Line 27:		Line 27:

	Constant Band Tracking consists in order analysis calculation based on energy summation from FFT data. Since the FFT module is used when tracking orders with the CBT feature, the trigger block duration is constant and no re-sampling is performed there. As a result, the number of rotation contained in one block depends on the rotating speed.		Constant Band Tracking consists in order analysis calculation based on energy summation from FFT data. Since the FFT module is used when tracking orders with the CBT feature, the trigger block duration is constant and no re-sampling is performed there. As a result, the number of rotation contained in one block depends on the rotating speed.
			[[NVGate_CBT_principle_and_settings\|See CBT page for more info.]]

	===To sum-up:===		===To sum-up:===

Lmagimel at 12:37, 29 April 2020

2020-04-29T12:37:37Z

← Older revision		Revision as of 14:37, 29 April 2020
Line 1:		Line 1:
			This article compare Synchronous Order Analysis (SOA) method versus Constant Band Tracking (CBT) method.
	==Applications==		==Applications==
	===Synchronous Order Analysis (SOA)===		===Synchronous Order Analysis (SOA)===

Lmagimel: /* Applications */

2020-04-29T12:35:37Z

Applications

← Older revision		Revision as of 14:35, 29 April 2020
Line 1:		Line 1:
	===~~Applications~~===		==Applications==
			===Synchronous Order Analysis (SOA)===


	* '''Synchronous Order Analysis (SOA)~~'''~~

	* Balancing / Phase default detection: order 1 is being followed. Phase gives the unbalance<nowiki>'</nowiki>s position.		* Balancing / Phase default detection: order 1 is being followed. Phase gives the unbalance<nowiki>'</nowiki>s position.
Line 12:		Line 9:
	* Orbit analysis / Angle analysis		* Orbit analysis / Angle analysis
	* Torsional analysis / Crank Shaft Analysis		* Torsional analysis / Crank Shaft Analysis
			===Constant Band Tracking (CBT)===
	* '''Constant Band Tracking (CBT)~~'''~~

	* Gear Boxes: shocks are numerous, spectra are noisy. Orders are not identified as clearly as they are in the case of large rotating machines such as turbines for instance. What is interested then is more the energy around one order rather than its amplitude. Computation is performed on a constant width frequency band.		* Gear Boxes: shocks are numerous, spectra are noisy. Orders are not identified as clearly as they are in the case of large rotating machines such as turbines for instance. What is interested then is more the energy around one order rather than its amplitude. Computation is performed on a constant width frequency band.

	* '''Order Extraction from waterfall~~'''~~		===Order Extraction from waterfall===

	* For investigation. When people don<nowiki>'</nowiki>t know precisely what they are looking for (which order or frequency band to follow). The FFT waterfall can be used as a first step evaluation before using eventually SOA or CBT for in-depth analysis.		* For investigation. When people don<nowiki>'</nowiki>t know precisely what they are looking for (which order or frequency band to follow). The FFT waterfall can be used as a first step evaluation before using eventually SOA or CBT for in-depth analysis.

	~~{\|cellspacing~~=~~"0" cellpadding~~ = ~~"10" style="border-style:solid; border-color:black; border-width:1px;" width="100%"~~		==Principles==
	~~\|<font color~~=~~"#4F81BD"><font size~~ = ~~"4">'''''2/ Principles'''''</font></font>~~

	\|}		===SOA===

	* '''SOA~~'''~~

	It is an order analysis method for which the sampling is synchronous with the rotating speed measured from the tachometer. Re-sampling filters are used on the raw signal to give constant angle sampling and a triggered blocks size independent from the rotating speed (the size corresponds to a fixed number of revolutions).		It is an order analysis method for which the sampling is synchronous with the rotating speed measured from the tachometer. Re-sampling filters are used on the raw signal to give constant angle sampling and a triggered blocks size independent from the rotating speed (the size corresponds to a fixed number of revolutions).

	* '''CBT~~'''~~		===CBT===

	Constant Band Tracking consists in order analysis calculation based on energy summation from FFT data. Since the FFT module is used when tracking orders with the CBT feature, the trigger block duration is constant and no re-sampling is performed there. As a result, the number of rotation contained in one block depends on the rotating speed.		Constant Band Tracking consists in order analysis calculation based on energy summation from FFT data. Since the FFT module is used when tracking orders with the CBT feature, the trigger block duration is constant and no re-sampling is performed there. As a result, the number of rotation contained in one block depends on the rotating speed.

	To sum-up:		===To sum-up:===

	* SOA trigger block is based on a constant revolution number defined by the order resolution and in sync with the tachometer pulses.		* SOA trigger block is based on a constant revolution number defined by the order resolution and in sync with the tachometer pulses.
Line 53:		Line 46:
	* The SOA averaging is done on the exact same number of revolutions at any time of the measurement whereas the CBT will average different number of revolutions at sparate time of the test depending on the current rotating speed.		* The SOA averaging is done on the exact same number of revolutions at any time of the measurement whereas the CBT will average different number of revolutions at sparate time of the test depending on the current rotating speed.

	~~{\|cellspacing~~=~~"0" cellpadding~~ = ~~"10" style="border-style:solid; border-color:black; border-width:1px;" width="100%"~~		==Swept sine setup emphasizing differences between SOA and CBT techniques==
	~~\|<font color="#4F81BD"><font size = "4">'''''3/~~Swept sine setup emphasizing differences between SOA and CBT techniques~~'''''</font></font>~~

	\|}

	A 1V-RMS swept sine is set up to go from 100 to 200Hz (6000 to 12000RPM). Order 1 is tracked using CBT and SOA. Frequency resolution is 5Hz in the frequency domain (2kHz bandwidth <nowiki>+</nowiki> 401 lines).		A 1V-RMS swept sine is set up to go from 100 to 200Hz (6000 to 12000RPM). Order 1 is tracked using CBT and SOA. Frequency resolution is 5Hz in the frequency domain (2kHz bandwidth <nowiki>+</nowiki> 401 lines).

	* '''CBT~~'''~~		===CBT===

	To begin with, the minimum frequency band (15Hz) is selected for the tracking of order 1. The profile from 6500RPM to 11500RPM for order 1 is the following:		To begin with, the minimum frequency band (15Hz) is selected for the tracking of order 1. The profile from 6500RPM to 11500RPM for order 1 is the following:
Line 78:		Line 68:
	Energy around order 1 in a 45Hz bandwidth is now included in the computed value. As the energy distributed on the lines of the FFT spectrum comes, in this case, only from order 1, we are therefore clearly getting closer to the 1V RMS by enlarging the bandwidth and combining those lines.		Energy around order 1 in a 45Hz bandwidth is now included in the computed value. As the energy distributed on the lines of the FFT spectrum comes, in this case, only from order 1, we are therefore clearly getting closer to the 1V RMS by enlarging the bandwidth and combining those lines.

	* '''SOA~~'''~~		===SOA===

	The order 1 tracked with the SOA plug-in gives a value which is consistent with RPM (see below). The tracked order is never "released" with such technique, no matter what the RPM value is. That is why the result is a straight line and no "steps" are seen in the profile.		The order 1 tracked with the SOA plug-in gives a value which is consistent with RPM (see below). The tracked order is never "released" with such technique, no matter what the RPM value is. That is why the result is a straight line and no "steps" are seen in the profile.
Line 84:		Line 74:
	[[Image:SOA_Vs_CBT_07.png\|framed\|none]]		[[Image:SOA_Vs_CBT_07.png\|framed\|none]]

	* '''Phase information~~'''~~		===Phase information===

	Below are the complete ''Bode'' plots (with phase information) of order 1 profiles we get respectively from the SOA plug-in and from the CBT.		Below are the complete ''Bode'' plots (with phase information) of order 1 profiles we get respectively from the SOA plug-in and from the CBT.
Line 96:		Line 86:
	On the contrary, the phase of the SOA is always -90° because the order is "held" during the whole computation process.		On the contrary, the phase of the SOA is always -90° because the order is "held" during the whole computation process.

	~~{\|cellspacing~~=~~"0" cellpadding~~ = ~~"10" style="border-style:solid; border-color:black; border-width:1px;" width="100%"~~		==Tachometer setup==
	~~\|<font color~~=~~"#4F81BD"><font size~~ = ~~"4">'''''4/Tachometer setup'''''</font></font>~~

	\|}

	The setup of the tachometer is very important for the accuracy of the phase results. Since different setup can lead to slightly different results, it is necessary to know what to pay attention to. The difference between AC and DC coupling will be here emphasized as one of those important settings.		The setup of the tachometer is very important for the accuracy of the phase results. Since different setup can lead to slightly different results, it is necessary to know what to pay attention to. The difference between AC and DC coupling will be here emphasized as one of those important settings.

Lmagimel at 12:32, 29 April 2020

2020-04-29T12:32:09Z

← Older revision		Revision as of 14:32, 29 April 2020
Line 1:		Line 1:
	~~{\|cellspacing~~=~~"0" cellpadding~~ = ~~"10" style~~=~~"border-style:solid; border-color:black; border-width:1px;" width~~=~~"100%"~~		===Applications===
	~~\|<font color~~=~~"#4F81BD"><font size~~ = ~~"4">'''''1/ Applications'''''</font></font>~~

	\|}

	* '''Synchronous Order Analysis (SOA)'''		* '''Synchronous Order Analysis (SOA)'''

← Older revision		Revision as of 22:30, 12 June 2020
Line 1:		Line 1:
	This article ~~compare~~ Synchronous Order Analysis (SOA) method ~~versus~~ Constant Band Tracking (CBT) method.		This article compares Synchronous Order Analysis (SOA) method to the Constant Band Tracking (CBT) method.
	==Applications==		==Applications==
	===Synchronous Order Analysis (SOA)===		===Synchronous Order Analysis (SOA)===

	* Balancing / Phase default detection: ~~order~~ 1 is being followed. Phase gives the unbalance<nowiki>'</nowiki>s position.		* Balancing / Phase default detection: Order 1 is being followed. Phase gives the unbalance<nowiki>'</nowiki>s position.
	* ~~Cost~~ Down using Bode Plot. Critical frequencies can be detected (Amplitude and Phase)		* Coast Down using Bode Plot. Critical frequencies can be detected (Amplitude and Phase)

	[[Image:SOA_Vs_CBT_01.png\|framed\|none]]		[[Image:SOA_Vs_CBT_01.png\|framed\|none]]
Line 12:		Line 12:
	===Constant Band Tracking (CBT)===		===Constant Band Tracking (CBT)===

	* Gear Boxes: shocks are numerous, spectra are noisy. Orders are not identified as clearly as they are in the case of large rotating machines such as turbines for instance. What is ~~interested then~~ is more ~~the~~ energy around one order rather than its amplitude. Computation is performed on a constant width frequency band.		* Gear Boxes: shocks are numerous, spectra are noisy. Orders are not identified as clearly as they are in the case of large rotating machines such as turbines for instance. What is interesting is their is more energy around one order rather than its amplitude. Computation is performed on a constant width frequency band.

	===Order Extraction from waterfall===		===Order Extraction from waterfall===
Line 27:		Line 27:
	===CBT===		===CBT===

	Constant Band Tracking consists in order analysis calculation based on energy summation from FFT data. Since the FFT module is used when tracking orders with the CBT feature, the trigger block duration is constant and no re-sampling is performed there. As a result, the number of ~~rotation~~ contained in one block depends on the rotating speed.<br>		Constant Band Tracking consists of order analysis calculation based on energy summation from FFT data. Since the FFT module is used when tracking orders with the CBT feature, the trigger block duration is constant and no re-sampling is performed there. As a result, the number of rotations contained in one block depends on the rotating speed.<br>

	[[NVGate_CBT_principle_and_settings\|See CBT page for more info.]]		[[NVGate_CBT_principle_and_settings\|See CBT page for more info.]]
Line 36:		Line 36:
	* FFT trigger block for CBT has a constant time base defined by the frequency resolution.		* FFT trigger block for CBT has a constant time base defined by the frequency resolution.

	The example below shows, at two different rotating speeds of a swept sine~~, respectively the FFT trigger block and the SOA trigger block~~.		The example below shows, respectively the FFT trigger block and the SOA trigger blocks at two different rotating speeds of a swept sine.

	[[Image:SOA_Vs_CBT_02.png\|framed\|none]]		[[Image:SOA_Vs_CBT_02.png\|framed\|none]]
Line 48:		Line 48:
	This is different in the FFT module where the average time is the same for the whole range of speeds.		This is different in the FFT module where the average time is the same for the whole range of speeds.

	* The SOA averaging is done on the exact same number of revolutions at any time of the measurement whereas the CBT will average different number of revolutions at ~~sparate~~ time of the test depending on the current rotating speed.		* The SOA averaging is done on the exact same number of revolutions at any time of the measurement whereas the CBT will average different number of revolutions at a separate time of the test depending on the current rotating speed.

	==Swept sine setup emphasizing differences between SOA and CBT techniques==		==Swept sine setup emphasizing differences between SOA and CBT techniques==
Line 93:		Line 93:


	The setup of the tachometer is very important for the accuracy of the phase results. Since different ~~setup~~ can lead to slightly different results, it is necessary to know what to pay attention to. The difference between AC and DC coupling will be here emphasized as one of those important settings.		The setup of the tachometer is very important for the accuracy of the phase results. Since different setups can lead to slightly different results, it is necessary to know what to pay attention to. The difference between AC and DC coupling will be here emphasized as one of those important settings.

	<u>Measurement setup</u>: one tachometer is connected to both Ext ~~Sync~~ 1 and 2 and both ~~Input~~ 1 and 2. The different signals are:		<u>Measurement setup</u>: one tachometer is connected to both Ext Syncs 1 and 2 and both Inputs 1 and 2. The different signals are:

	* Train pulses with AC coupling (in black)		* Train pulses with AC coupling (in black)