My first post here, I'm in learning mode, this seemed like the most appropriate thread.
I found this circuit (on-line) with a reference to the MegaSquirt project. I'm not sure which version of MegaSquirt this circuit was used in, as the posted schematics appear slightly different.
My question relates to the 1n4733A zener.
During the positive portion of the input signal, the diode within the opto will limit input voltage to about 1V
During the negative portion of the input signal, the 1n4003 diode will limit input voltage to about -1V
It seems like the zener has no purpose, can someone explain?
I also noticed that this version of the circuit (http://www.msextra.com/doc/general/ms1v3schems.html) has provision for either an ignition coil signal or a VR signal, however the opto based circuit (similar to above circuit) appears to be for the ignition coil signal not the VR signal. Perhaps the first opto based circuit posted above was used for either signal in an earlier version?
Variable reluctance sensor circuit
Forum rules
Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
Variable reluctance sensor circuit
You do not have the required permissions to view the files attached to this post.
-
Bernard Fife
- Master Squirter
- Posts: 475
- Joined: Thu Oct 29, 2009 12:54 pm
Re: Variable reluctance sensor circuit
Jester,
This circuit isn't used on any of the MegaSquirt main boards, so it's hard to comment. Perry hasn't posted here for years. You can try the email pedward@dainst.com (from the schematic), or you might try Googling his name ("Perry Harrington" from the schematic), to see if you can contact him and ask him about the circuit.
Lance.
This circuit isn't used on any of the MegaSquirt main boards, so it's hard to comment. Perry hasn't posted here for years. You can try the email pedward@dainst.com (from the schematic), or you might try Googling his name ("Perry Harrington" from the schematic), to see if you can contact him and ask him about the circuit.
Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it.” - George Bernard Shaw
Re: Variable reluctance sensor circuit
An LED will be destroyed by too much current flow through it. Since a VR sensor produces a varying voltage output with speed - as well as fequency - the zener will clip the voltage across the LED to the safe level.
Dave P, London UK.
Rover V-8
MSII V3
EDIS
Tech Edge Wideband
Rover V-8
MSII V3
EDIS
Tech Edge Wideband