the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
icon

AP60B Needs Higher VSS Frequency


Post ReplyPost New Topic
< Prev Topic Next Topic >
teliocide 
Member - Posts: 2
Member spacespace
Joined: June 07, 2018
Location: Australia
Posted: June 07, 2018 at 10:20 PM / IP Logged  
I have installed a Command Ap60B on a Mitsubishi Delica.
I have used the VSS output connection that is on the back of the instrument panel.
It works fine but the lowest speed it works at is 50kph.
There are now many many 40 zones everywhere.
I need the CC to work at 40kph to minimize my donation rate to the police.
There are a few jumper-links on the AP60B circuit board to assist matching the VSS output to the AP60B.
Unfortunately these affect the higher speeds as well.
There is only one setting that will allow the CC to work at 40 kph but with this setting the cc will not function above 80 kph.
I need to double the frequency from the VSS and feed this to the CC.
The vss output is not a square wave, its rectangular. If it was square the solution is very very easy. BUT its not.
So does any one know how to increase the frequency of the VSS output while preserving the duty cycle (signal shape)?
Dakota Digital do have a device to do this, but I have no idea how it works.
Thanks in advance
KPierson 
Platinum - Posts: 3,527
Platinum spaceThis member consistently provides reliable informationspace
Joined: April 14, 2005
Location: Ohio, United States
Posted: June 16, 2018 at 1:24 AM / IP Logged  
I'm not sure what you mean by "rectangular". Are you saying that the frequency is always the same but the duty cycle is changing to reflect speed? If the Ap60B is reading the frequency at all I would think that there would be a frequency component to it.
What is the frequency of the VSS at 50kph? 25kph? 75kph? What is the duty cycle at these speeds?
Kevin Pierson
teliocide 
Member - Posts: 2
Member spacespace
Joined: June 07, 2018
Location: Australia
Posted: June 16, 2018 at 6:21 PM / IP Logged  
A square wave has a 50% duty cycle. A rectangular wave has a duty cycle between 0% and 100%.
The VSS signal here is about 20%. Basically a pulse followed an interval with the interval significantly longer than the pulse.
The AP60B operates on frequency.
The duty cycle does not change.
There are many easy ways to double the frequency of a 50% duty cycle square wave.
Easy to find circuits for this as microprocessor clock speeds need to be changed.
Data clocks are 50% duty cycle.
These methods do not work correctly when the duty cycle is not 50%.
The case here 20%, the output becomes 2 pulses and a long interval.
The cruise control sees this as garbage.
All resolved now with 2 circuits.
First convert the VSS to 50% duty cycle and then double the frequency via the simple methods above.

Sorry, you can NOT post a reply.
This topic is closed.

  Printable version Printable version Post ReplyPost New Topic
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

  •  
Search the12volt.com
Follow the12volt.com Follow the12volt.com on Facebook
Friday, March 29, 2024 • Copyright © 1999-2024 the12volt.com, All Rights Reserved Privacy Policy & Use of Cookies
Disclaimer: *All information on this site ( the12volt.com ) is provided "as is" without any warranty of any kind, either expressed or implied, including but not limited to fitness for a particular use. Any user assumes the entire risk as to the accuracy and use of this information. Please verify all wire colors and diagrams before applying any information.

Secured by Sectigo
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
Support the12volt.com
Top
the12volt.com spacer
the12volt.com spacer