NVGate Torsional - Revision history

Lmagimel: /* Frequency to RPM converter (Torsional inputs) */

2026-10-02T08:06:55Z

Frequency to RPM converter (Torsional inputs)

← Older revision		Revision as of 09:06, 2 October 2026
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	Max RPM = (40 000*64)/pulse per revolution example : 12 800 RPM with 200 Pls/rev<br>		Max RPM = (40 000*64)/pulse per revolution example : 12 800 RPM with 200 Pls/rev<br>

	· Missing teeth management: up to 3 consecutive teeth.<br>		· Missing teeth management: up to 4 consecutive teeth.<br>

	· Available filters: HighPass, LowPass; BandPass, StopBand, Integrator (single or double) and differentiator<br>		· Available filters: HighPass, LowPass; BandPass, StopBand, Integrator (single or double) and differentiator<br>
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	\|}		\|}

	* '''Pulse / rev''': the number of pulses per revolution. The user can enter an integer value between 1 and ~~4092~~. For a non-integer number of pulses per revolution the user must use a virtual tach.<br>		* '''Pulse / rev''': the number of pulses per revolution. The user can enter an integer value between 1 and 4096. For a non-integer number of pulses per revolution the user must use a virtual tach.<br>

	*[[NVGate_Tachometer#Ext._Tach\|other parameters are defined on page tachometer: ext synch .]]		*[[NVGate_Tachometer#Ext._Tach\|other parameters are defined on page tachometer: ext synch .]]

Lmagimel: /* Twist measurements (static and dynamic) */

2026-10-01T15:35:15Z

Twist measurements (static and dynamic)

← Older revision		Revision as of 16:35, 1 October 2026
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	The twist will be displayed in angle or torque (setting ''Physical qty.''). The coefficient is used to convert the read angle in torque.<br>		The twist will be displayed in angle or torque (setting ''Physical qty.''). The coefficient is used to convert the read angle in torque.<br>

	When ''Physical qty.'' = '''Torque''', the setting ''Coef.'' appears. It is the torsional stiffness of the shaft and it must be entered in '''N·m per radian''' (N·m/rad), not in N·m per degree. ~~NVGate does not display this unit.~~		===coefficient===
			When ''Physical qty.'' = '''Torque''', the setting ''Coef.'' appears. It is the torsional stiffness of the shaft and it must be entered in '''N·m per radian''' (N·m/rad), not in N·m per degree.
	{\|class="wikitable"		{\|class="wikitable"
	\|'''Torque (N·m) = Coef. (N·m/rad) × twist angle (rad)'''		\|'''Torque (N·m) = Coef. (N·m/rad) × twist angle (rad)'''

LaurentM OROS: Twist: unit of Coef. in Torque mode (N·m/rad), conversion from N·m/°, Offset

2026-10-01T15:33:33Z

Twist: unit of Coef. in Torque mode (N·m/rad), conversion from N·m/°, Offset

← Older revision		Revision as of 16:33, 1 October 2026
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	[[Image:Release_note_26.png\|700px\|none]]		[[Image:Release_note_26.png\|700px\|none]]

	The twist will be displayed in angle or torque. The coefficient is used to convert the read angle in torque.<br>		The twist will be displayed in angle or torque (setting ''Physical qty.''). The coefficient is used to convert the read angle in torque.<br>

			When ''Physical qty.'' = '''Torque''', the setting ''Coef.'' appears. It is the torsional stiffness of the shaft and it must be entered in '''N·m per radian''' (N·m/rad), not in N·m per degree. NVGate does not display this unit.

			{\|class="wikitable"
			\|'''Torque (N·m) = Coef. (N·m/rad) × twist angle (rad)'''
			\|}

			* If the stiffness is known in N·m/°, multiply it by 57.3 (180/π). Example: 5000 N·m/° → enter ''Coef.'' = 286 479.
			* Example measured on the bench: twist 5.5° (= 0.096 rad) with ''Coef.'' = 1000 → torque = 96 N·m (and not 5500 N·m).
			* The ''Offset'' is an angle (in °), added to the twist '''before''' the coefficient: Torque = Coef. × (twist + Offset).

	The result are available from the add/Remove windows under the virtual input tab.		The result are available from the add/Remove windows under the virtual input tab.

Lmagimel: /* Limits */

2026-10-01T15:15:15Z

Limits

← Older revision		Revision as of 16:15, 1 October 2026
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	* Near a whole number (g = 1.95, 2.0, 2.05), setting that whole number is correct on both sides; setting the lower whole number fails as soon as the gap exceeds it		* Near a whole number (g = 1.95, 2.0, 2.05), setting that whole number is correct on both sides; setting the lower whole number fails as soon as the gap exceeds it
	* In post-processing, when the ''Tach'' option of Signal Op. is used, check that the ''Missing teeth'' value of the created tachometer (''Tachometer > Ext. tach. 1'') is the same as the Tors one.		* In post-processing, when the ''Tach'' option of Signal Op. is used, check that the ''Missing teeth'' value of the created tachometer (''Tachometer > Ext. tach. 1'') is the same as the Tors one.
	* It is recommended to set the instrumentation in order to limit the number of missing pulse below 3s~~'''~~: Indeed long interval without pulses will lead to a strong order 1 artefact in the instantaneous speed signal due to interpolation of sample. Remaining below 3s for the missing pulse provide correct measurements.		* It is recommended to set the instrumentation in order to limit the number of missing pulse below 3s: Indeed long interval without pulses will lead to a strong order 1 artefact in the instantaneous speed signal due to interpolation of sample. Remaining below 3s for the missing pulse provide correct measurements.

	===Tutorial ===		===Tutorial ===

Lmagimel: /* Limits */

2026-10-01T15:14:58Z

Limits

← Older revision		Revision as of 16:14, 1 October 2026
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	* Near a whole number (g = 1.95, 2.0, 2.05), setting that whole number is correct on both sides; setting the lower whole number fails as soon as the gap exceeds it		* Near a whole number (g = 1.95, 2.0, 2.05), setting that whole number is correct on both sides; setting the lower whole number fails as soon as the gap exceeds it
	* In post-processing, when the ''Tach'' option of Signal Op. is used, check that the ''Missing teeth'' value of the created tachometer (''Tachometer > Ext. tach. 1'') is the same as the Tors one.		* In post-processing, when the ''Tach'' option of Signal Op. is used, check that the ''Missing teeth'' value of the created tachometer (''Tachometer > Ext. tach. 1'') is the same as the Tors one.
	*It is recommended to set the instrumentation in order to limit the number of missing pulse below 3s''': Indeed long interval without pulses will lead to a strong order 1 artefact in the instantaneous speed signal due to interpolation of sample. Remaining below 3s for the missing pulse provide correct measurements.		* It is recommended to set the instrumentation in order to limit the number of missing pulse below 3s''': Indeed long interval without pulses will lead to a strong order 1 artefact in the instantaneous speed signal due to interpolation of sample. Remaining below 3s for the missing pulse provide correct measurements.

	===Tutorial ===		===Tutorial ===

Lmagimel: /* Fractional missing pulses management */

2026-10-01T15:14:50Z

Fractional missing pulses management

← Older revision		Revision as of 16:14, 1 October 2026
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	<font color="#0070C0"><u>''''' Piano tape junction for fractional missing pulse management'''''</u></font>		<font color="#0070C0"><u>''''' Piano tape junction for fractional missing pulse management'''''</u></font>

	The empty area (missing teeth) length at the piano tape junction must be included between 1 and 3 teeth. The number of missing teeth must be set to the '''integer part''' of the gap length: in this example (gap of 2.x teeth): 2. See the [[#Quick guide for the operator: what to enter in NVGate\|quick guide for the operator]] below.		The empty area (missing teeth) length at the piano tape junction must be included between 1 and 4 teeth.

	~~Note: the total number of teeth includes the missing teeth. By example, an encoder with '''24 pulse/rev''' and '''1 missing teeth''' must be set as :~~
	~~[[Image:Torsional_Setup_With_MissTeeth.png\|700px\|none]]<br>~~


	~~[[Image:front_end_22.png\|framed\|none]]~~

	~~'''Attention''': The time lap of the first missing pulse must be longer than twice the time lap of the previous pulse interval~~

	'''It is recommended to set the instrumentation in order to limit the number of missing pulse below 3s''': Indeed long interval without pulses will lead to a strong order 1 artefact in the instantaneous speed signal due to interpolation of sample. Remaining below 3s for the missing pulse provide correct measurements.

	====Quick guide for the operator: what to enter in NVGate====		====Quick guide for the operator: what to enter in NVGate====
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	* Near a whole number (g = 1.95, 2.0, 2.05), setting that whole number is correct on both sides; setting the lower whole number fails as soon as the gap exceeds it		* Near a whole number (g = 1.95, 2.0, 2.05), setting that whole number is correct on both sides; setting the lower whole number fails as soon as the gap exceeds it
	* In post-processing, when the ''Tach'' option of Signal Op. is used, check that the ''Missing teeth'' value of the created tachometer (''Tachometer > Ext. tach. 1'') is the same as the Tors one.		* In post-processing, when the ''Tach'' option of Signal Op. is used, check that the ''Missing teeth'' value of the created tachometer (''Tachometer > Ext. tach. 1'') is the same as the Tors one.
			*It is recommended to set the instrumentation in order to limit the number of missing pulse below 3s''': Indeed long interval without pulses will lead to a strong order 1 artefact in the instantaneous speed signal due to interpolation of sample. Remaining below 3s for the missing pulse provide correct measurements.

	===Tutorial ===		===Tutorial ===

Lmagimel: /* Limits */

2026-10-01T13:28:32Z

Limits

← Older revision		Revision as of 14:28, 1 October 2026
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	NVGate allows achieving angular sampled analysis avoiding the artefacts introduced by the direct angular sampling.		NVGate allows achieving angular sampled analysis avoiding the artefacts introduced by the direct angular sampling.



	~~=====Limits=====~~
	* The gap must be at least 1 tooth long, i.e. the gap interval must be longer than twice the normal interval. With a shorter gap (g = 0.6 tested), no setting gives a correct speed (spikes of 37 to 39 %).
	* Near a whole number (g = 1.95, 2.0, 2.05), setting that whole number is correct on both sides; setting the lower whole number fails as soon as the gap exceeds it (g = 2.05 set to 1 → +1.8 %).
	* In post-processing, when the ''Tach'' option of Signal Op. is used, check that the ''Missing teeth'' value of the created tachometer (''Tachometer > Ext. tach. 1'') is the same as the Tors one.

Lmagimel: /* Check after setting */

2026-10-01T13:28:13Z

Check after setting

← Older revision		Revision as of 14:28, 1 October 2026
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	=====Check after setting=====		=====Check after setting=====
	Run the shaft at a constant speed and look at the Tors signal: it must be '''flat''', with '''no spike once per revolution''', and its mean value must match the speed given by another sensor. If not, see the typical mistakes below.		Run the shaft at a constant speed and look at the Tors signal: it must be '''flat''', with '''no spike once per revolution''', and its mean value must match the speed given by another sensor. If not, see the typical mistakes below.



			=====Limits=====
			* The gap must be at least 1 tooth long, i.e. the gap interval must be longer than twice the normal interval.
			* Near a whole number (g = 1.95, 2.0, 2.05), setting that whole number is correct on both sides; setting the lower whole number fails as soon as the gap exceeds it
			* In post-processing, when the ''Tach'' option of Signal Op. is used, check that the ''Missing teeth'' value of the created tachometer (''Tachometer > Ext. tach. 1'') is the same as the Tors one.

	===Tutorial ===		===Tutorial ===

Lmagimel: /* Annexe : Setting Pulse/rev and Missing teeth */

2026-10-01T13:27:39Z

Annexe : Setting Pulse/rev and Missing teeth

← Older revision		Revision as of 14:27, 1 October 2026
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	NVGate allows achieving angular sampled analysis avoiding the artefacts introduced by the direct angular sampling.		NVGate allows achieving angular sampled analysis avoiding the artefacts introduced by the direct angular sampling.

	~~==Annexe : Setting Pulse/rev and Missing teeth ==~~
	With a piano tape, the gap at the junction is never a whole number of teeth: it is, for example, 2.4 teeth, never exactly 2 or 3. NVGate handles such a fractional gap perfectly, '''provided that the two settings are chosen as described below'''.

	~~[[File:Torsional_piano_tape_gap.png\|800px\|none]]~~
	~~<font color="#0070C0">''Piano tape with P = 58 pulses present per revolution and a gap of g = 2.4 teeth''</font>~~

	~~=====What the two settings mean=====~~
	~~{\|class="wikitable" style="width:100%;"~~
	~~!Setting!!Meaning~~
	\|-
	~~\|'''Pulse / rev''' (N)\|\|Total number of tooth positions on one revolution, '''missing teeth included'''.~~
	\|-
	~~\|'''Missing teeth''' (m)\|\|Number of missing teeth (the gap).~~
	\|-
	~~\|'''N − m'''\|\|Number of pulses '''actually present''' on one revolution (P). This is the decisive value: it must match the real number of pulses.~~
	\|}

	~~=====Setting rule=====~~
	~~{\|class="wikitable" style="width:100%;"~~
	~~\|style="background:#E8F0FA;"\|~~
	~~# '''Count P''', the number of pulses actually present on one revolution (black stripes of the tape, or pulses between two gaps on a recording).~~
	~~# '''Measure g''', the gap length in teeth: '''g = (gap interval ÷ normal interval) − 1'''.~~
	~~# '''Missing teeth = integer part of g'''. If g is within 0.1 of a whole number, use that whole number.~~
	~~# '''Pulse/rev = P + Missing teeth''' — not the "nominal" number of stripes of the tape.~~
	\|}

	~~'''Example''': 58 pulses present and a gap interval 3.4 times the normal interval → g = 2.4 → '''Missing teeth = 2''' and '''Pulse/rev = 58 + 2 = 60'''.~~

	~~=====How to measure P and g on site=====~~
	~~# Run the shaft at a roughly constant speed and record the Ext. sync. track for a few revolutions.~~
	~~# On the recording, read the normal interval between two pulses and the interval across the gap. Compute g = (gap interval ÷ normal interval) − 1. Example: 3.4 ms ÷ 1.0 ms − 1 = 2.4 teeth.~~
	~~# Count the pulses between two gaps: this is P.~~
	~~# Check the result: at constant speed the Tors signal must be flat (no spike once per revolution), and its mean value must equal the speed given by another sensor (or by the same input in Tach mode).~~

	~~=====What happens with a wrong setting=====~~
	The following results were measured with NVGate 18.00.003 on an OR35, with synthetic pulse trains whose pulse instants are exactly known (58 pulses present per revolution, 1200 RPM constant, gap g from 0.6 to 4.0 teeth, 63 cases). Results are identical online (Ext. sync. input) and in post-processing (Signal Op.).

	~~[[File:Torsional_missing_teeth_map.png\|900px\|none]]~~
	<font color="#0070C0">''Error on the mean speed (%) depending on the actual gap g and on the settings. Colour = worst of mean and peak error. Left: Pulse/rev = P + m. Right: Pulse/rev kept at the nominal value 60.''</font>

	~~{\|class="wikitable" style="width:100%;"~~
	~~!Setting!!Example (g = 2.4, P = 58)!!Result~~
	\|-
	~~\|style="background:#5EF86D;"\|'''Missing teeth = integer part of g''', Pulse/rev = P + m\|\|m = 2, Pulse/rev = 60\|\|Correct in all tested cases (g = 1.0 to 4.0): mean error < 0.002 %, peak error < 0.035 %~~
	\|-
	~~\|Missing teeth rounded up\|\|m = 3, Pulse/rev = 61\|\|Correct only when the decimal part of g is large enough (1.7 → 2, 2.4 → 3 are correct, but 1.3 → 2 gives −57 %)~~
	\|-
	~~\|style="background:#FBBCB7;"\|One tooth less than the integer part\|\|m = 1, Pulse/rev = 59\|\|Speed '''too high by +1.6 to +2.9 %''', with no visible spike — the most misleading error~~
	\|-
	~~\|style="background:#FBBCB7;"\|One or two teeth too many\|\|m = 4, Pulse/rev = 62\|\|Speed too low by −2 % up to '''−68 %''' (speed divided by two)~~
	\|-
	~~\|style="background:#FBBCB7;"\|Missing teeth = 0 although there is a gap\|\|m = 0, Pulse/rev = 58\|\|Mean speed nearly correct, but a '''spike of 37 to 65 %''' once per revolution~~
	\|-
	~~\|style="background:#FBBCB7;"\|Pulse/rev kept at the nominal value whatever m\|\|Pulse/rev = 60, m = 3\|\|Correct only if Pulse/rev − m equals P. Otherwise +0.7 to +3.6 %, or worse~~
	\|}

	=====Limits=====		=====Limits=====

Lmagimel: /* Typical mistakes (example: 8 pulses, gap of 2.4) */

2026-10-01T13:26:50Z

Typical mistakes (example: 8 pulses, gap of 2.4)

@@ Line 152: / Line 152: @@
 =====Check after setting=====
 Run the shaft at a constant speed and look at the Tors signal: it must be '''flat''', with '''no spike once per revolution''', and its mean value must match the speed given by another sensor. If not, see the typical mistakes below.
 ===Tutorial ===