Author Topic: Truck PTO (Power Take-Off) Controller  (Read 785 times)

gurari

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Truck PTO (Power Take-Off) Controller
« on: December 22, 2016, 12:50:26 AM »
Hello everybody,
I'm starting a new project in which a Moteino will be involved. The project will be a controller for switching ON/OFF the PTO of a truck. The PTO (Power Take-Off) is mounted on the one of outputs of a automated gearbox, so the controller will be dealing also with the gearbox. So in order to deal with the safety issues I have to monitor some condition of the vehicle (vehicle standstill, parking brake engaged, engine running, etc..). These conditions are 28V analog signals so I want to ask more experienced with electronics guys which is the best way to hook them to moteino because obviously this little guy expects 3.3V signals? Should I use voltage divider or relay or something else?
For this moment this is what is bothering me. In the meantime I'm writing the logic for controlling the PTO valve. Any help will be appreciated.
Thanks in advance

Felix

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Re: Truck PTO (Power Take-Off) Controller
« Reply #1 on: December 22, 2016, 02:20:27 PM »
I would suggest using one of these switching regulators:
https://lowpowerlab.com/shop/product/133
Very nice units, up to 36v input.
For vehicle DC projects I would trow in a MOV or TVS transient protector specific for AUTO applications to protect from over/under voltage surges and other such noise from a car battery.
See this app note for details.

gurari

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Re: Truck PTO (Power Take-Off) Controller
« Reply #2 on: December 22, 2016, 04:46:26 PM »
Hello Felix,
Thank you for information provided.
For powering the project I've selected exactly the same little dc converter. I'm very happy with the performance of this little guy.
For the signals that I have to monitor (parking brake engaged, engine running, etc) they are coming from a dedicated ECU so I hope they should be stable and a simple voltage divider will do the trick. Also I have a lot of https://store.comet.bg/CatalogueFarnell/Product/646877/ which I can use for greater stability or just some LM7805's because there I don't have power consumption.
Tomorrow I'll read the article about the varistors.

Felix

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Re: Truck PTO (Power Take-Off) Controller
« Reply #3 on: December 22, 2016, 06:37:43 PM »
I'm no expert but I'd expect if you get power from the ECU then that line is already behind some varistor/tvs protection against transient/dump load/undervoltage battery events. Maybe something to look into. Either way it won't hurt to add your own protection.