So moving on to the lane Change. I know some of this has been covered in darainbow's Carerra Hybrid thread, but will leave that now to his conversion progress reports.
So first a look at the circuit board.
Working Round.
Power from the rails.
Input from the deadstrip.
Comparator. I would have thought they could have fed the signal straight to to the Microcontroller A-D. Obviously some additional signal conditioning was needed.
I had first assumed this would be the 5V regulator. The 5V must come from somewhere else? Perhaps one of the diodes.
Atmel tiny26L, same as the in-car controller. J4 is again in circuit serial programming.
Finally the solenoid drive circuitry, Diode to protect against back EMF and a 3NF06L Mosfet. Quite beefy with 4 Amp continuous drive.
I decided to measure the current taken by the board on a lane change. I do not expect this to be the problem it is with SSD as the LC's are only operated when a car wants to change lanes as opposed to every time the sensor is crossed.
Here's the trace measured across a 0.1 ohm resistor. Not sure why it's so noisy. Perhaps thats why they have added the LM393 comparator.
The pulse length is as has been described. Dependant on car speed. It varies from 25mS to 200ms.
This one is a 200mS pulse, pushing the car through quite slowly. There will be a minimum speed these work at, but you will probably have stalled on the dead strip by then.
Not sure how they measure the speed. Could either be time on the deadstrip, or determined by how many ident bursts are received.
So the maths are 2 Amps for 0.2 second worst case. It is easily possible that 2 cars could cross lane changers simultaneously so perhaps 4 Amps which is significant, however as the time is 200mS worst case I do not think it will be a problem. Lessons have been learnt.
Finally I think worth repeating these notes on analogue usage.
QUOTE (RichG @ 9 Dec 2006, 10:49)
<{POST_SNAPBACK}>It looks very clear that Ninco like Scaley have bussed the tracks across in the Lane Changers to improve the power distribution.
Now I know Ninco Bob has on SCI said.
QUOTE But you MUST use the NINCO 10401 Double Power Power Base (the "Blue" one... the one that uses 2 separate power supplies) rather than the standard 10101 Powerbase that comes with every analog set, because each lane of the N-Digital lane change track sections must be independently powered when used in an analog layout.
I think as ever he is looking through his Rose Tinted Glasses.
It doesn't matter if you have one PSU or two, if the rails are joined you ain't gona have control of two cars.
So this wire will need removing, track should still be fine in Digital mode, assuming the lanes are bridged in the Powerbase track. All the other Digital specific tracks will also need checking. Pit Lane, Control Tower, Multi Lane and Digital sensor tracks.
Rich
