Servo control on 3 way turnouts.

[Enterprisingwestern]

Apologies if this has already been covered, but I can't find it.

How do you ensure that the switch blades of a 3 way point operate in the correct order, ie, each servo throws before/after the other to save mangling the blades up?

Is there an electronic way of doing it, I don't have enough room to fit more microswitches in a flip flop fashion to do the job.

 

Mike.

[Crosland]

What's generating the servo control pulses and what control inputs does it have?

 

You need to gate the control pulses so that one servo moves at a time in the correct order or sequence the inputs to the controller.

 

Alternatively, a mechanical solution with a single servo moving between three positions.

 

Or a mechanically interlocked lever frame connected to the controller.

[Enterprisingwestern]

What's generating the servo control pulses and what control inputs does it have?

 

Megapoints controller feeding MG90S servos.

 

You need to gate the control pulses so that one servo moves at a time in the correct order or sequence the inputs to the controller.

 

But how?

 

Alternatively, a mechanical solution with a single servo moving between three positions.

 

Existing turnout with seperate point blades.

 

Or a mechanically interlocked lever frame connected to the controller.

 

Will be done from a control panel

 

Mike.

[BG John]

I may need to do this on a layout that will either use DC or radio control. I'll use an Arduino to operate each servo individually, with a time delay to give the first one time to finish moving before the second one starts. I don't know how practical it is to link an Arduino into your system, but it might be worth considering.

[Izzy]

If you throw the blades via a switch on the control panel linked to the megapoints board then fitting DPDT ones will allow one side to act as an on/off switch for the paired switch, so that when thrown one way the other switch won't energise it's servo. If the 3-way point is a tandem though, then the blades will be far enough apart that this isn't needed. Only with assymetrical 3-ways does the problem arise.

 

Izzy