Hey guys,
I need to transmit serial data over a distance of approximately 20 yards and I understand that TTL level serial max's out at around 24 feet. I could of course use RS-232 but I was wondering if I can just boost the TTL serial to a higher voltage and then step it down when it reaches the other board. Or maybe it would be just easier to use a MAX chip and use RS-232?
What do you guys think?
20 yards = 18 meters.
Boosting the signal or using a transmitter/receiver chip is all the same to me.
You could use RS232.
But better is RS485. Do you have twisted pair ? That would be ideal for the RS485.
but I was wondering if I can just boost the TTL serial to a higher voltage and then step it down when it reaches the other board.
Yes, it is simpler than that. Drive it through an open collector transistor with a pull up to 12V or so. Then catch it with a transistor at the other end. You will find is is good for over 500m.
So RS-485 is just RS-232 but in a "buss" mode so it can handle multiple devices? Is there a benefit for this if only two devices are linked? I'm trying to avoid getting into different communication algorithms if its possible since I am using C instead of the arduino environment, and this buss needs to be ultra-reliable. It is for a safety shutdown board (peoples lives may depend on it, etc....)
So RS-485 is just RS-232 but in a "buss" mode so it can handle multiple devices?
No. It is a differential system so for full duplex you need four wires.
since I am using C instead of the arduino environment,
The arduino environment is C.
this buss needs to be ultra-reliable
No such thing.
It is for a safety shutdown board (peoples lives may depend on it, etc....)
The system I described was used on access control systems that had to work as well as peoples lives depended on it.
I said C implying that I do not have access to arduino libraries...
The board is for a hydraulic running robot that uses 3000psi of pressure, can't say what it is but Discovery channel is coming in a few months...
Just tell me what the fastest and most reliable protocol/technique is please
Just tell me what the fastest and most reliable protocol/technique is please
That is not possible because speed and reliability are mutually exclusive.
Fastest is a simple asynchronous protocol.
Reliability is a packet system with check sums and message acknowledgements / repeating requests.