Confused with TACHINPUT
Moderators: jsmcortina, muythaibxr
Confused with TACHINPUT
Hello all,
I am using MS3 on v3.00 board. I am simply following the assembly instructions from the link:
http://www.megamanual.com/ms2/V3assemble.htm
I am planning to use Hall Effect sensor to read engine crankshaft hence I have built the circuitry with opto-isolator as mentioned in the page above. I have tested the input circuitry with JimStim without any problems, ie. I am able to read RPM with Tuner Studio.
However when I read from the MS3(base)/V3.0 Hardware Guide from the link:
http://www.msextra.com/doc/pdf/MS3baseV ... re-1.4.pdf
I realized that document mentions to wire TACHSELECT to VRIN for both in sections 5.2.3 and 5.2.4 (ie. meaning that one needs to build VR circuitry)
At this point I am a bit confused, could you please explain me what is going on?
Sincerely.
I am using MS3 on v3.00 board. I am simply following the assembly instructions from the link:
http://www.megamanual.com/ms2/V3assemble.htm
I am planning to use Hall Effect sensor to read engine crankshaft hence I have built the circuitry with opto-isolator as mentioned in the page above. I have tested the input circuitry with JimStim without any problems, ie. I am able to read RPM with Tuner Studio.
However when I read from the MS3(base)/V3.0 Hardware Guide from the link:
http://www.msextra.com/doc/pdf/MS3baseV ... re-1.4.pdf
I realized that document mentions to wire TACHSELECT to VRIN for both in sections 5.2.3 and 5.2.4 (ie. meaning that one needs to build VR circuitry)
At this point I am a bit confused, could you please explain me what is going on?
Sincerely.
Re: Confused with TACHINPUT
Don't use the MegaManual if using Extra Code. Use the ones linked to at the top of this page. They were written for Extra Code.
Rover SD1 3.5 EFI
MS2 V3
EDIS
Tech Edge O2
London UK.
MS2 V3
EDIS
Tech Edge O2
London UK.
Re: Confused with TACHINPUT
Ok I understand. I shouldn't use MegaManual. This becomes clear for me after reading the link:
http://megasquirt.info/educational/
Nevertheless what is your comments on tach input? It works just perfect, and as far as my understanding on schematics (schematics from msextra) optoin circuitry seems more convenient for a Hall Effect sensor as a tach input. As I have mentioned before, RPM signal reading is just working with opto circuitry with JimStim.
Sincerely.
http://megasquirt.info/educational/
Nevertheless what is your comments on tach input? It works just perfect, and as far as my understanding on schematics (schematics from msextra) optoin circuitry seems more convenient for a Hall Effect sensor as a tach input. As I have mentioned before, RPM signal reading is just working with opto circuitry with JimStim.
Sincerely.
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- Super MS/Extra'er
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Re: Confused with TACHINPUT
FWIW...... I absolutely recommend using the VR circuit!
Been there, done that!!!
Ken
Been there, done that!!!
Ken
1979 Corvette - 383 CID SBC w/ Holley Pro-Jection 900 CFM TBI, 4-85 lb lo-z injectors & Walbro 255 pump
MS2 v3 w/extra 3.4.2 Release
36-1, Delphi LS2/7 coils in wasted spark, driven by v2.0 logic board from JBPerformance
Spartan Lambda Sensor from 14point7
TinyIOX from JBPerformance
MS2 v3 w/extra 3.4.2 Release
36-1, Delphi LS2/7 coils in wasted spark, driven by v2.0 logic board from JBPerformance
Spartan Lambda Sensor from 14point7
TinyIOX from JBPerformance
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- Super MS/Extra'er
- Posts: 6828
- Joined: Sun May 15, 2011 11:41 am
- Location: Walnut Creek, Calif. USA
Re: Confused with TACHINPUT
Umm... if it is working fine, leave it as-is!
It can also work fine using the VR input, but no need to bother changing it now. Of course, if you ever "re-purpose" this MS to use (or temporarily try out) on a different install, you may wish you had finished the board and had VR or some adjustment for Hall threshold available.
PS: note that I have to take the OP's word that it really is working fine.
It can also work fine using the VR input, but no need to bother changing it now. Of course, if you ever "re-purpose" this MS to use (or temporarily try out) on a different install, you may wish you had finished the board and had VR or some adjustment for Hall threshold available.
PS: note that I have to take the OP's word that it really is working fine.
Re: Confused with TACHINPUT
It may work just fine. The problem *might* arise if using a hall effect with a multi-tooth wheel. The opto input may not be able to keep up with the number of pulses at very high revs.spiderman wrote:Ok I understand. I shouldn't use MegaManual. This becomes clear for me after reading the link:
http://megasquirt.info/educational/
Nevertheless what is your comments on tach input? It works just perfect, and as far as my understanding on schematics (schematics from msextra) optoin circuitry seems more convenient for a Hall Effect sensor as a tach input. As I have mentioned before, RPM signal reading is just working with opto circuitry with JimStim.
Sincerely.
Rover SD1 3.5 EFI
MS2 V3
EDIS
Tech Edge O2
London UK.
MS2 V3
EDIS
Tech Edge O2
London UK.
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- Experienced MS/Extra'er
- Posts: 187
- Joined: Sun Feb 12, 2006 6:26 pm
- Location: Va. Beach, VA
Re: Confused with TACHINPUT
It may work fine on the JimStim, but once reading the actual toothed wheel at high RPM's there could be hickups depending on the frequency response of the sensor.
Porsche 930 3.0 Slantnose
MS3/MS3X Sequential Injection & Spark, MS Knock, Dual plug, LS2 coils, Siemens 55 lb/hr HiZ injectors, ALM-ADV Wide Band,
Carrera Intake, Extrude honed, Ford 70mm Throttlebody, GTX3071R Turbo
MS3/MS3X Sequential Injection & Spark, MS Knock, Dual plug, LS2 coils, Siemens 55 lb/hr HiZ injectors, ALM-ADV Wide Band,
Carrera Intake, Extrude honed, Ford 70mm Throttlebody, GTX3071R Turbo
Re: Confused with TACHINPUT
Thank you so much all, I have decided to leave it as it is for now. I am going to use VR circuit if there are problems with optocoupler's response in real system.
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- Super MS/Extra'er
- Posts: 1986
- Joined: Sat Jul 22, 2006 8:02 pm
- Location: Eureka, NV USA
- Contact:
Re: Confused with TACHINPUT
Excellent choice, IMHO!spiderman wrote:Thank you so much all, I have decided to leave it as it is for now. I am going to use VR circuit if there are problems with optocoupler's response in real system.
Ken
1979 Corvette - 383 CID SBC w/ Holley Pro-Jection 900 CFM TBI, 4-85 lb lo-z injectors & Walbro 255 pump
MS2 v3 w/extra 3.4.2 Release
36-1, Delphi LS2/7 coils in wasted spark, driven by v2.0 logic board from JBPerformance
Spartan Lambda Sensor from 14point7
TinyIOX from JBPerformance
MS2 v3 w/extra 3.4.2 Release
36-1, Delphi LS2/7 coils in wasted spark, driven by v2.0 logic board from JBPerformance
Spartan Lambda Sensor from 14point7
TinyIOX from JBPerformance
Re: Confused with TACHINPUT
I use a bmw e46 330i with factory hall sensor and 60-2 wheel. Its working perfectly with the opto isolator circuit, only need to replace the C11 10n capacitor to a smaller, I use 330 pf.Dennis930 wrote:It may work fine on the JimStim, but once reading the actual toothed wheel at high RPM's there could be hickups depending on the frequency response of the sensor.
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