Field control - a technical analysis

[technik3k]

@jpearman

@Telemascope

@Telemascope Cases where a whole alliance disconnects at the same time are almost certainly due to field control

Believe me, it almost certainly isn’t.

@sazrocks

What is it then? I’ve been witnessing these simultaneous disconnects for four years now and am still baffled as to what causes them. The field control is the only common factor that I see every time an alliance simultaneously disconnects.

@jpearman

I don’t want to either derail this thread or get into a deep technical discussion here, but take a look at this;
Field control - a technical analysis - Technical Discussion - VEX Forum

James, could you go into more technical details in this thread then?

Here is a quote from one of your posts:

@jpearman

There are a few important things to understand about the field controller software.

1. Control is one way using two simple signals, there is no feedback from the joystick or robot to field control.

2. The field control is holding you robot in disable until released, that is, if for some reason field control was not working, a disconnected cable or something like that, then your robot will be enabled.

3. Field control does not use any form of “special” commands to your robot, it can not erase your program, it does not directly tell your robot what to do, it only “releases” your robot when the match starts.

4. If your alliance partner was released by field control and you did not move, then it’s not a field control problem. The signals that you are receiving are exactly the same as your alliance partner, in fact, you are directly connected to your alliance partner joystick through the driver interface.

@104232:

5. If both you and your alliance partner have problems when the match starts, it may be a field control problem, see the next section and check the leds on your joystick and the driver interface, they are there to help you.

#5 says that if both robots are affected than it may be a field control problem.

However, I have very hard time understanding what would be the mechanism of of both alliance partners being disconnected and reset mid match and somehow it is their fault and not the fault of the field hardware.

All field control components, including the cables are EP/field technicians domain, all internal Joystick components are non-modified VEX electronics.

If I understand correctly the only things that might be teams’ fault are:

1. Plugging cables incorrectly - then how come everything worked since the beginning of the game?
2. Having low joystick battery or intermittent battery connection - then why both robots undergo reset?
3. Having bad (shorting?) partner joystick cable - again how could this affect the other robot?
4. Shaking controller too much causing RJ45 to:
   a) disconnect - then why both robots are affected?
   b) short - then it is problem with the cable that is part of the field setup.

I am very puzzled.