ESU SwitchPilot Servo

[Biggless]

Hi, I am trying to program the addresses for some servo motors (linked to ESU SwitchPilot Servo) with my Hornby Elite. According to the instructions for the SwitchPilot, all I need to do is to;

1. Put the SwitchPilot in learning mode
2. Send a command from the Elite using the accessory number you want to asign to the servo motor (I followed instructions on p39 of Elite manual)

This doesn't work. The SwitchPilot Servo doesn't seem to accept the communication with the Elite. 

Any ideas ?

[2e0dtoeric]

I can't help with that, I've not used them.

[RDS]

Hi biggless

Have you got a Load connected to the servo's when you are trying to program them, because my understanding for the other output terminals, is that a Load is required.  Maybe it is the same for the servo outputs.

[Chrissaf]

Biggless,

 

It's been several hours and I am surprised that nobody has come back to you with anything definitively positive yet. I don't use Switch Pilots myself, but I'm aware of them via some other posts I have contributed to. I've had a search around and found this existing thread that might answer your question.

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https://www.hornby.com/forum/switch-pilot-decoder/

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Additionally, the following has been pasted from another thread I found in my search. The author of this post extract is 'Hornby Rail Master Support' themselves.

 

The ESU Switchpilot is a particularly awkward accessory decoder to program due to the requirements that must be in place.Where most people make mistakes are:-

 

1. Connecting the power and track cables from the Switchpilot to the DCC controller. It is important that the polarity of these two sets of cables are the same or programming will not work.

 

2. A load must be connected to port 1 on the accessory decoder. This does not need to be a resistor. A point motor will achieve the same thing.

 

Third thing you can do is put the search text "ESU" (without the quote marks) in the forum search box at the top of this page and click the green magnifying glass. This will return about 15 links to review relating to different aspects of ESU and Switch Pilot.

 

EDIT: I think the links above I found relate to using Switch Pilot with Solenoid points. Probably different with Servo's. Do you have the FULL ESU Switch Pilot manual or just the 'quick start' type guide. The FULL manual (2008 version) can be found here. It may give you clearer instructions for programming servos.

[Fishmanoz]

Hi Biggles, are you using the a hard copy version of the Elite manual?  I ask because accessing and programming points is not on page 39 of the latest manual (that is speed curves), it is on pages 57-59.  If you don't have it, download it from the Downloads section of this website.  But as it says on page 58, the instructions are applicable to R8427 accessory decoders and are definitely different for Switchpilot.  All you need from the Elite manual is how to select a point number, as described on page 57.

 

You should also ensure your Elite has been upgraded to the latest v1.41 firmware before you start - it should flash up 141 when it starts, not 13 or 14. You'll see where to find the upgrade when you look at Downloads, DCC Instruction Manuals to find the Elite manual.

 

Also as Chris says, you will need the full Switchpilot manual and he has given you the link.

 

Then can you please confirm to us you are trying to program servo point motors not solenoids. The Switchpilot has 4 outputs for solenoids (called transistor outputs) and 4 for servos.  Servo point motors are those such as Tortoise and Cobalt.  What point motors do you have?

 

If you can confirm all of that, you are right to go.  And note as Chris says, there is one recent and many older threads which have the full story on programming Switchpilots for solenoids.

 

The instructions for programming are on page 20 of the Switchpilot manual.  As an example, you can start by selecting point 1 with your Elite, put the Switchpilot into programming mode by pressing and holding the switch, follow the Elite instructions for throwing the selected point 1, and points 1-4 should be programmed.  Repeat with point 5 to program 5-8, 9 for 9-12 etc.  I'm unclear on the need for a load on transistor output 1 when programming servo outputs so you could try both ways if it doesn't work one way.

 

Read on in the Switchpilot manual on adjusting CVs if necessary for start-end positions etc.

[Pete172]

 I'll be watching this one with interest !

I will shortly be trying to program an ESU S/P Servo unit too...to actuate servo control for brass kit built semaphore signals. Ideally I want to control this via Railmaster, but I would consider it progress if I can get them working with my Elite first.

There is an instruction PDF on the Importer's site :

http://www.southwestdigital.co.uk/PDF/SwitchPilot/SWD%20Switchpilot%20Servo%20user%20sheet%20v4.pdf

Also - a video which makes it look easy ! :

Cheers,

P.

[Chrissaf]

I'm sure Fishmanoz won't get upset at me pointing out a correction to his post, after all he has corrected my errors enough times in the past. In his latest reply there is one line  "Servo point motors are those such as Tortoise and Cobalt". This is factually incorrect the ESU manual on page 7 states that the Servos are RC (Radio Control) type servos.

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For other readers who might not appreciate the difference then read on:

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Tortoise and Cobalt point motors are two wire controlled. They contain an electric motor that drives the actuator against an end stop and effectively stalls the motor at the end of travel. You then reverse the applied voltage to drive the motor in the other direction to the other end end stop. Thus, there is no mid position, only all the way one way or the other.

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RC Servos are three wire devices, they have a +ve supply voltage rail (typically 6volts) a -ve volt rail (typically 0volts) and a control wire. The control wire contains a square wave signal with a pulse width that is variable between 75 and 225 miliseconds (ms). When the pulse width is 150 ms the servo is in the mid position. A pulse width of 75 ms drives the servo motor to the limit of its travel in one direction. A pulse width of 225 ms drives the servo to the limit of its travel in the other. For any fixed pulse width between 75 and 225 ms, the servo will move to a position that is proportional to the pulse width being applied and stay there until the pulse width changes. In RC terms, think of a model plane rudder control, you don't want the rudder either all the way to the left or to the right, you want to have precise control over the whole range of movement and hold the rudder at any point inbetween, including the mid position for straight ahead flight. This feature is acheived by varying the pulse width applied to the servo third wire by the RC servo control receiver circuit.

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EDIT: I have just watched the video link in Pete172 post. This video should make the setting up idiot proof, it is very comprehensive.

[Pete172]

 You are correct about the servos, not to be confused with Cobalts etc..

All - Have a look at the 2 links in my post above....from what I can gather, it may be best to connect up the servo motor first (not to introduce a load - don't think this is needed with the servo decoder/ though it is with the standard Switchpilot for solenoid's) and get it working using just the buttons on the decoder unit. Once this is achieved, then progress to configuring the DCC operation...via Elite/cv's ?

 

 

[Chrissaf]

One other correction to previous replies:

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I've just spotted that in Biggless original post he clearly states in the first sentence that he is using "ESU Switch Pilot Servo". This ESU decoder model is physically different to the Solenoid supporting Switch Pilot.

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• The solenoid version has four transistor controlled solenoid outputs PLUS two servo outputs.
• The 'ESU Switch Pilot Servo' has four servo outputs only and NO solenoid outputs.

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The fact that both versions support servos in some capacity is what I think is causing confusion.

[Chrissaf]

One final thought for consideration:

 

I have worked with RC servos on other (non point control) projects. I have found that you can wire two (in fact more than two) RC servos in parallel to the same control port and they will mimic each other. This could be useful for point crossovers. The only issue is to select two (or more) servos that have matched electrical & mechanical characteristics (e.g same brand, same part number) so that they all move by the same amount of travel when operated from a single common port. In the RC world, you can buy servo 3 pin Y cables to perform this very wiring configuration as it can be a desirable feature to implement in RC model control.

[Fishmanoz]

No problem pointing out the servo thing Chris.  We are all here to help after all.

 

The trouble is that the manual uses servo in 2 contexts.  Yes, it talks about the 2 x RC 3-wire servo outputs.  But then it also talks about 4 x 2-wire outputs and calls them interchangeably motor and servo outputs, and it also talks about using a product called Switchpilot Extension with these latter.  In my previous I ignored the 2 x 3-wire and made my comments about the motor outputs.  So if Biggles is talking about the 3-wire, he can ignore my comments.  And I just noticed it says they have a built-in load so don't need one attached for programming. 

 

If people weren't confused about these decoders previously, they sure should be now!