TACHO PROBE
Contents
1. Automotive Energy amp Power Analysis Field Service Environmental Research amp Development TACHO PROBE Manual About the content of this document The information contained in this document is subject to change without notice DEWETRON elektronische Messgeraete Ges m b H DEWETRON shall not be liable for any errors contained in this document DEWETRON MAKES NO WARRANTIES OF ANY KIND WITH REGARD TO THIS DOCUMENT WHETHER EXPRESS OR IMPLIED DEWETRON SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE DEWETRON shall not be liable for any direct indirect special incidental or consequential damages whether based on contract tort or any other legal theory in connection with the furnishing of this document or the use of the information in this document Version 1 0 APR30 2010 Page 1 1 Introduction and BASICS ccc cc ecceccececccceccececcececcececceceacenegueceaueceeuectenesueaesuecesneauecesuenesueaesnesuentanes 3 CNO al ee 4 DM OE TACHO PROBE DEE 4 22 OE TACHO PROBE On a AES 5 20 ESPAGEOSPROBE 0 ue etn a Reo ne fe eo ee ee en oe eee 5 SARAIOUUS E EE 6 Sol c AMATO GUC NO UE EE 6 32 emule e 7 93 XephPM abd Angle le E 8 3 3 1 Create Analogue Tacho Counter Sensor 8 Se E une lee TAG EE 10 94 PRE e ele E E 11 A AGIWIStable COUMICK Se loe Eo eae 13 CFA NG NON EE 14 51 Credt angle based2. Page 17
3. a new trigger will be only detected if Retrigger value is crossed before So If signal is noisy around trigge level double trigger could appear With set retrigger we could overcome this Version 1 0 Aug 2011 Trigger edge Trigger level v Positive 4 15 Find Retrigger time V Retrigger level Bypass Y Frequency 9 3 Is Page 9 Tacho Probe DR 3 3 2 Setup sampling rate INFO We are in setup mode so DEWESoft is running with the setup sampling rate The setup sampling rate which is actually set could be seen like this Create a new Setup or Start DeweSoft the sampling rate shown now in the Dynamic acquisition rate is the setup sampling rate If the trigger signal is very fast it could be that it is not possible to see the shape and therefore a reliable trigger in the angle math In this case the setup sampling rate has to be set higher gt Global Setup gt Setup sampling rate RNA Project Hardware setup Project setup Global settings set sampling rate according to tacho signal Version 1 0 Aug 2011 Page 10 Tacho Probe 3 4 Results channels The angle math will output Trigger signal with a duration of 1 sample every time the edge is detected The frequency in Hz And a angle signal from 0 360deg This is possible because we only have one puls per revolution So start and stop is defined In case CD
4. 1 Pulse rev or an other sensor must be used CDM TRIG sensor Encoder with Zero Pulse Version 1 0 Aug 2011 Page 11 Tacho Probe ee ns het Scope 22 osse E Se i c2 Q CX ESI Mo oni AS LAM d MEL IL val gt acceleration Tacho probe z3 woe dece cm wow eat Be be oe eee weit bee we Ee eel Ss ew we ee we a es e 22 Math ee Oe Tacho probe Tigger e e e e e e e e e e e e e e e e e e i e e e e e e e e e e e e e e T Tacho probe Angle Tacho probe Frequency 2223 E Tacho probe Angle deg Tacho probe T rigger Tacho probe V 4 0 11 0 18 0 25 0 32 0 39 0 46 0 53 0 60 0 To get speed in RPM a simple math formula can be used to calculate the rpm signal Tacho probe Frequency 60 Basic operators gt e Now the angle math was insert manually to get out engine speed and angle Version 1 0 Aug 2011 Page 12 Tacho Probe 4 Adjustable counter Setup As mentioned if adjustable counter is available or if no analogue amplifier with supply voltage SE TACHO PROBE 02 should be used In this configuration the probe is supplied from the Counter and the output signal is provided on BNC cable and also on the LEMO Counter input of the counter Source of counter x e Channel setup for channel EO CNTO Basic application Reset V Reset on start measure Sensor encoder CDM tacho Y Input filter Bus At the adjustable counter in com
5. KEE 14 92 orcinec 15 S EE ise EE TI I UU Tm 15 S ROME aS RR SE 15 C PE elei 16 Version 1 0 APR30 2010 Page 2 Tacho Probe 1 Introduction and Basics Most of the time a rom measurement is needed at rotating machines The reasons could be very different Sometimes it is only an additional information to all the other measurement channels and sometimes particular analysis like Order tracking Balancing averaged Orbit require this So we need to install a rom sensor For sure there are several sensors on the market So we could use an encoder the DEWETRON RIE Sensor or only other reflecting probes that deliver a signal which is related to engine speed All this sensors could be used But sometimes this takes a lot of effort to mount such sensors Imagine an encoder or even the RIE Sensor this will take a while to install and sometimes it is simply not possible to mount because of space limitations So to find a reliable and easy to install sensor is not that easy For sure not all sensors can fulfil the requirements needed at specific applications For example a Tacho Probe with one pulse could not be used to do a rotational vibration analyse Here a few Probes are introduced which could help to solve the rpm measurement on rotating machines Version 1 0 Aug 2011 Page 3 Tacho Probe 2 Tacho Probe This sensor was mainly designed to measure a pulse coming from an reflective tape or any other object which re
6. M sensor is set up angle will run continuously up so we will not get an angle signal running from 0 to 360deg Why Example CDM sensor is used on screw heads lets assume we get 6 pulses 6 screws so we could extract the frequency the Trigger signal and also the Angle Every screw pulse will equal 360 62 60deg So first pulse is Odeg next will be 60deg the last will be 360 or Odeg It would be possible to reset every 6 screw Lets assume we do that and do an angle based measurement like described at 4 1 At that measurement we could see a peak around 240deg If we stop the measurement now and restart it the peak will be at 120deg even if nothing was changed on the machine At an other restart it will be at 300deg and on a other restart we could see it again maybe on 240deg Why The start is not defined at a CDM sensor So at the first measurement where the peak was inni num seen at 240deg the angle math started on screw 1 on the second it started on screw 3 SO Start and end is not defined and we can not get a defined phase angle out of it To avoid errors the angle will run only up at a 0 en 420 180 240 300 en CDM sensor 360 360 But some applications need a defined start 0 60 120 180 240 position to get reproducible angle Order 360 tracking Balancing or if want to have comparable angle based measurement So if this needed Trigger Probe must be operated in Tacho Mode
7. OBE 02 Here the Probe is connected to a Voltage input module with BNC or to an adjustable counter input The TX power supply will always come from d A SA the counter input 12V The probe has got an additional adapter Ree cable with LEMO and BNC prepared to connect directly e 1 DEWE CNT ADJ 1x 650R 0 5W oder 2x 1k3 emo connector is connected to Counter A__ pin 1 12v Input for power supply NN The output signal is provided via BNC and li IN also via LEMO including supply to counter 4 4 l 1 NR o0 in case adjustable counters are E installed this could be used instead of ege meng analogue input SIS LEMO TPol DIN female TPolDIN male housing Resistors in housing 30cm of connector This connection to counter input of the Lemo is always there even if no adjustable counter is installed because it will not disturb the output signal BNC OUT Voltage input with BNC connector LEMO Counter Input TTL LMEO Counter Input Adjustable 2 3 SE TACHO PROBE 0x If there is a need to connect the probe to any other input module only the adapter cable has to be modified So please contact your local DEWETRON dealer for further assistance Version 1 0 Aug 2011 Page 5 Tacho Probe 3 Analogue Setup 3 1 Analogue Input Here either SE TACHO Probe 01 or SE TACHO Probe 02 could be used Probe 01 will be supplied directly from analogue input amplifier where Probe 02 wil
8. Shafts or 5 3 ge gees other rotating parts this probe is very easy x e e and fast to setup For further information lt please refer to Order tracking or Balancing a rs tonnes NC user manual Trial weight position B Correction weight position 270 5 4 Rpm measurement The probe is also perfectly suitable for a fast and quick rom measurement oo additionally rpm signal to all the other signals Version 1 0 Aug 2011 Page 15 6 Specifications Length Temperature range Min Frequency Max Frequency Supply Voltage Current consumption typically phase shift Tacho Probe 140mm 10 60 lt 10Hz depending on Reflection about 10kHz depending on reflection 9 15V DC 25mA 1Pulse rev 50kHz sampling rate 100K 600rpm Odeg 6000rpm 6deg depending on reflection measured on test pad This probe is working on the principle of light received So reflection and sharpness of object will define the output signal Because waveform can change with speed trigger position changes and therefore the angle position That s why it is suitable for RPM measurement but not for high accurate phase measurement Applications Balancing Order tracking Common RPM measurement Version 1 0 Aug 2011 Page 16 SYSTEM TECHNOLOGY SWEDEN AB Version 1 0 Aug 2011 www systemtech se Tel 013 35 70 30 sales systemtech se Linn gatan 14 582 25 LINKOPING Tacho Probe
9. ape was used to reduce the reflection once per revolution The distance should be about 1 2cm depending on reflection Version 1 0 Aug 2011 Page 6 Tacho Probe 3 2 Check the Signal Before rpm is extracted with further math functions we should check the tacho signal 1 8079 Tacho probe V 1 0422 14765 13108 2 246 2 296 2 346 2 396 2 446 Z On the shaft of the engine a black tape is used to create the trigger pulse So every time the black tape passes the reflection decreases and therefore the voltage output of the trigger probe drops We could see a nice trigger signal which will give us a volatge drop every revolution But we can also observe a small drops between which is caused from an other part on the shaft which decreases the reflection like dirt or rust But this will not disturb because it is very small compareed to the main signal so if we set the right trigger level 1 5V for the rom detection we will get a nice signal In case the trigger level is not high enough or is burried under noise the probe must be readjusted to get a clear trigger pera revolution Version 1 0 Aug 2011 Page Tacho Probe 3 3 Get RPM and Angle signal Now we have to extract the angle and the frequency to get rom and a angle based view if this is required gt For this an angle sensor mathematic is prepared in the math Basic section of DEWESoft ee DS des Other Triggering analvei At Latch math e A
10. flects light SE TACHO PROBE 0x It is used to measure the speed of a rotating shaft rpm or it could be also used to create a trigger event based on a reflection The sensor is emitting light LED which is reflected from an us object and received from a photo transistor T1 So the output of this sensor is an analogue voltage signal which is proportional to OUT the reflected light GND A white color mark a screw head a flute or something similar will already produce different light reflection and therefore a signal which could be used to trigger The typically distance to the object is about 2cm The sensor has to be connected to an analogue input channel of a Dewetron measurement system Depending on the Input connector DSUB BNC the power supply will be provided from the Analogue input channel or from the counter input There are two connector options available 2 1 SE TACHO PROBE 01 Here the power supply comes from the analogue f input amplifier 5o no additional power supply or any 4 i connector is needed to operate the probe es NN y SZ The probe could be directly connected to this input amplifiers of DEWETRON NEL MDAQV 200 MDAQ Bridge DEWE 43 di DAQP LV ee a HSI LV Pin 7 IN OF DAQP Frequ A i VVVVVV Pin 2 IN m Shield to Trigger Probe E housing 9pol DSUB Male Resistors in DSUB conector of Probe Version 1 0 Aug 2011 Page 4 Tacho Probe 2 2 SE TACHO PR
11. l be supplied out of counter and signal will be measured from analogue input amplifier BNC INPUT 9 M Tacho DAQP LV 0 Used Hy 50 V 300 kHz BE i 9 acceleration DAQP ACC A i 5000 mV 300 kHz Exc 4 m Analogue Trigger probe is connected to a volatge amplifier DAQP LV of channel 0 The volatge input of the tacho probe is set to 25V tacho probes power supply is 12 V so the maximum signal we get will be about 11V Therefore 25V Range is suitable for it Filter is set to 3OKkHz There is no scaling needed trigger probe output is volatge which will be later used to get the speed of the machine The example was related to DAQP LV amplifier If other amplifier is used voltage should be set gt 10V and filter should be set gt 50kHz or to highest value In case reflection is changing over time DC component of the signal could change here AC coupling of the input would could help In this case trigger level will become relative In case of noise lower filter should be used INFO Be aware that a low filter will shift the PHASE at different engine speeds which could influence the measurement Now the sensor could be pointed to the rotating part of the machine To get one pulse per revolution a color mark screw head flute or a strong black tape or reflection stripe must be available on the shaft to get a nice signal In our case a black t
12. ngle sensor He Scope trigger Onthe left we have to specify the input channel which reflects our tacho signal gt The sensor type describes which sensor is connected EE Name Tacho probe Trigger Tacho probe 1 Pulse rev color ME CDM sensor x Pulses rev screw heads of a flange 60 2 b8pulses and 2 are missing are a few examples of sensor types For more information refer to online help PRESS F1 of DEWESOFT online help In our case we have 1 puls rev so it is a analogue tacho signal This Tacho sensor must be created in the Counter Sensor editor of DeweSoft 3 3 1 Create Analogue Tacho Counter Sensor Help y Settings gt Settings gt Counter sensor editor will open the counter sensor editor Project d Hardware setup amp Counter sensors editor Project setup EXIT Global setup ana Remove sensor Save amp Exit Cancel ol PLE E Ta Sensor editor Signal type Signal filter S Analog voltage Y 100 ns x H7 Counter sensor editor ids Signal edge Default trigger level V 0 5 v SI units editor Negative In the editor we create a new sensor called Tacho Analog and select Tacho for sensor Type Tacho type is always 1 Pulse per revolution Page 8 Version 1 0 Aug 2011 LL E e Addsensor Removesensor Save amp Exit Cancel EH nal leve Signal type Signal filter Analog voltage Y 100 n
13. parison to non adjustable counter input the Trigger level and also retrigger level could be entered So in other words we can set trigger level from 0 to 40V To do this we have to set the Trg Type to CUSTOM After that the trigger level and retrigger level could be entered Sensor type Tacho Analog sensor type will be also Tacho or CDM and result output will be angle and speed in Hz or rpm Also here only Tacho Signal 1pulse rev will deliver an angle signal from 0 to 360deg If CDM is used Angle will continuously run up Why it similar to analogue Tacho sensor like described in 3 4 Even if the adjustable counter is used the output signal should be checked first like described in section 3 2 output on BNC cable Because without a visual view it would be hardly possible to set the right Trigger and Retrigger level in the counter setup If the probe is connected to adjustable counter one more analogue input channel would be available and at very high input frequencies of tacho probe counter would give better frequency resolution Version 1 0 Aug 2011 Page 13 Tacho Probe 5 Applications 5 1 Create angle based view The Tacho probe delivers RPM and also an angle signal If now XY diagram is used and angle is applied to x axis and for example acceleration or any other signal to y axis this signal could be shown angle based XY Recorder Watt Transparent Unified prope
14. rties o Tacho probe Angle deg Tacho probe T rigger Tacho probe V acceleration mV gt E ZS E amp O o Kl Tacho probe Angle deg o0 on the right we could see the signal time based and on the left the signal is shown angle based At XY Diagram graph type has to be changed to angle based xy view and after that number of periods revolutions could be chosen INDO At XY diagram deselect all channels first The first channel applied after will be the X channel and the next one s are used for the Y channel s Version 1 0 Aug 2011 Page 14 Tacho Probe 5 2 Order tracking Also Order tracking needs rpm signal if the probe is used in Order tracking the Order tracking module will add this Angle Math function automatically and use the results out of it Setup will be the same all settings are controlled out of Order tracking module and therefore it will be locked in the math section For further information please refer to Order tracking user Manual EE Frequency source EE Tacho probe Tacho probe Trigger Analog pulses 4 x Tacho probe Y Tacho probe Angle 5 3 Balancing For Balancing application this is the perfect ee probe Also Balancing needs Order tracking er Enn and therefore a speed rpm and angle DEED signal And for balancing Fans
15. s k Signaledge Positive sl Default trigger level V 0 5 Tacho Probe lf we get more pulses from the analogue trigger probe because we are looking to the screw head of a flansch where 5 screws are used we have to use the Geartooth CDM sensor type Signal type is indicating which type of signal we get from the probe In our case we get an analog voltage so we have to set this to analogue volatge Signal filter is used if tacho signal has noise on it so it has to be high for at least 100ns that it will be counted Signal edge predefines if pos or neg slope is used to trigger and also a default trigger level could be set gt itis possible to enter a value in the DEFAULT trigger level field INFO Signal type is used for filtering the sensor so if Digital TTL is selected instead of analogue it will not appear in the Sensor list of Ordertracking if Analogue Pulses is used as source The same if Counter sensor is set up as analogue sensor and should be used when Counter is selected as frequency source in Ordertracking The next Step is to enter the trigger levels and the retrigger level So module will find the edge and calculate frequency and angle between those From point 3 2 where we checked the signal in the recorder we could see that about 1 5V and 1 4V would be the right settings for trigger and retrigger Retrigger is working like this After a trigger was detected 1 5V
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