Mercury tach signal

[martin]

Can someone please help me out on this tach signal... I need some technical info on what kind of signal is this..I cannot measure the voltage of tach cause the outboards off boat.. I am wanting to experiment with a PLC and HIM..basically I'm wanting to be able to read the signal and display on a touch screen..as well as temp. Volts, pressure ..fuel flow basically build my own interface with carbed 99 150 hp mercs

[FLexpat]

If you don't want to reinvent the wheel this will get it all to a NMEA2000 bus:
http://www.nolandeng.com/rs11.php

[martin]

Originally Posted by FLexpat

If you don't want to reinvent the wheel this will get it all to a NMEA2000 bus:
http://www.nolandeng.com/rs11.php

Thanks for the info.... Btw how is your project coming

[FLexpat]

Originally Posted by martin

Thanks for the info.... Btw how is your project coming

VERY slowly - not much gets done if I don't get within 1000 miles of the boat.
Just working on stuff that I can do remotely now - like electrical system design.

[flyingfrizzle]

Originally Posted by martin

I am wanting to experiment with a PLC and HIM..basically I'm wanting to be able to read the signal and display on a touch screen..

Having some PLC stuff laying around and some panel view touch screens I have thought about the same type of thing but for may race car not the boat. Cool idea but a lot of tech for an boat. It would be cool tho. You could monitor air temp, water temp, motor temp, motor water pressure, you name it. If you could find a sensor to throw on it. Far as the tach you would need to scale the pulses from the un-rectifier signal off of the grey wire to be able to translate it to RPM. You could add a magnetic pick up to the fly wheel to measure VPP also.

I though of adding Thermo couples on each of my exhaust tubes in the headers to have egt's along with all the other common items you would want to monitor on a drag car. Some basic logic to run the water pump and fans so that it would maintain a set point of 160 degrees. But like flex said, there are too many built for the purpose items out there to thro a PLC in a car or boat unless you just wanted to do it just because. For racing Holly (carburetor manufacture) and several other manufactures has got into efi computers that act as plcs and trend and run logic. They can be set up to monitor and run about what ever you want. Also Race Pak came out with a deal called Hot Wire. This is basically a miniature 12 volt based PLC for cars. It has its own simple programing method and soft ware that comes with it as well as thousands of sensors that can be added. Analog to simple discreet signals, there are pick ups for drive shaft loops for RPM and wheel speed sensors to determine the wheel slip compared to the drive shaft speed that can be set up for traction control. It can break back power to keep the car from spinning by backing timing out or boost or what ever you set it up to do.

If you had the stuff to play with it would be a neat project. I always wanted to do something crazy like that myself. If you had to purchase something to do this I would look towards getting a simple set up that was already designed for 12 volts. Check out the smart wire system from race pack: http://www.racepaksmartwire.com/

I am adding one of these units to my car this year and going to add as many sensor as I can afford to add. Plans are to record the data and trend it to a data acquisition system so I can see what the car is doing or reacts to changes. I want to also swap over to an efi set up which will give me even more data and adjustability on the timing and fuel curves. The days of a simple MSD box with timing retard pills are over. Im sill running one (7al3) and a lot of people do but the electronically controlled future is apond us.