Megapoints or Tam Valley...

[ColHut]

I am looking to intall quite a number of servos for point motors, and I am trying to decide between the Megapoints or Tam Valley controllers. I would need 1.5 times as many Octopods as MP controllers, but otherwise the prices seem about the same total cost per servo. The TV appear to have a nifty servo setting tool, and the US-AUD exchange rate is certainly better than the UK-AUD one. The MP will probably need less cards installing.

 

But otherwise I would love to hear any comments either way.

 

regards

[Crosland]

With servos you need to consider where the servos are related, relative to the control boards. Sometimes boards with fewer output are better, rather than trying to extend the servo cable to a distant servo.

 

The answer may even be to use a mix of the two types.

 

Buy one of each and see which works best with your chosen servo. Check for any jerking or twitching at start up.

[Ian Morgan]

If you are OK with a soldering iron, Merg kits work out much cheaper (£1.55 per servo if you go for the Servo4 kit), but you do need to be a member.

[Crosland]

You can also a get a MegaPoints controller in kit form from MERG. 

[Mike K]

I've got a Megapoints controller board here just for demo purposes at the moment, as I havent started my new layout yet.  Very impressed, very easy to use, and so far, very reliable.  Added to which a couple of queries I had before buying it, Dave was very prompt and very detailed in his reply, so I would recommend his customer service back up, if you have any problems any time.

 

Just one thing to remember, that depends on how you want to control them, but if your planning on using DCC, the Megapoints system needs a DCC connector add-on, which is extra cost.  If your controlling them through switches its fine - if you are planning to have more than 12 points, then I *think* on the Megapoints system, there is a point (no pun intended!) where it becomes cheaper to go for a panel controller board.  I dont want to tell you wrong however, so if your looking at more than 12 points (or the points are spaced out) I would encourage you to drop an email to Dave explaining what you want to do, how you want to control them, the number of points and asking him what would be the best and most cost-effective way of doing it with his system.  At least then you can make an informed choice between the two?

 

No connection other than as a customer, but would highly recommend those. I've no experience of the other one you mention.

 

Mike

[young37215]

There is an existing Megapoints thread which is worth a read if you are considering their product.

 

http://www.rmweb.co.uk/community/index.php?/topic/103795-megapoint-controllers/page-9&do=findComment&comment=3075590

 

I have no experience of using any other servo control system and am an electrical dunce. Despite these constraints I have managed to successfully install several Megapoints servo controllers, a Multipanel driven by my own control panel and am running a network in excess of 21 metres all to my satisfaction (and astonishment!).

[ColHut]

Thanks all. Control will ultimately be via Modratec locking frames with auxiliary switch units. I would like the concurrent option of DCC control as well but the thought of isolating the locking frame and having to reset all the points for the last way the frame was set is too daunting at this stage!

 

I will look more at the control panel options.

 

I had read the other thread which I thought most interesting.

 

regards

Edited April 16, 2018 by ColHut

[njee20]

The newest MegaPoints boards remove power to the servos 1 second (IIRC) after they move, so no twitching. Seems to work well.

 

The DCC modules are £30, and the multi panel board (which interfaces with the DCC module) is £84, ergo if you're more than 3 boards, and want DCC, then you should get the multi panel processor. 3 or fewer boards and you may as well buy a DCC module for each board.

I run multiple servos off a single output for things like crossovers which works well. Again the newest boards have a higher output to cope with such activities. You can reach a point with the older ones where they get overloaded and shut down.

 

No comment on the Tam Valley ones though I'm afraid.

[Mike K]

Thanks all. Control will ultimately be via Modratec locking frames with elecmek on-on switches. I would like the concurrent option of DCC control as well but the thought of isolating the locking frame and having to reset all the points for the last way the frame was set is too daunting at this stage!

 

I will look more at the control panel options.

 

I had read the other thread which I thought most interesting.

 

regards

 

Hi Col,

Which DCC system do you have?  A friend of mine has had a number of discussions with Harold at Modratec about this, and I believe Harold modified his frame, there was an extra locking lever added i think - i'll have to ask to find out how. 

 

I know he uses Digitrax, and has CML TowerMaster cards connected to the emeck switches on the Modratec frame, so that when the frame throws and depresses the switch, it energies a momentary relay, that sends a single pulse to the TowerMaster card (the card in fact thinks that a push-to-make has been depressed) and the card then sends the DCC message out to control the points.  All works very very well, but TowerMaster only work on Digitrax I think.  However, you could combine the Modratec frame with the Megapoints system in that style if you wanted DCC.

 

Failing that of course, the Modratec emeck switches could just be the switches direct to the megapoints control.  Feel free to PM me if you want more info and i can always put you in touch.

 

Mike

[ColHut]

Thanks Mike, will do. I use the NCE powercab system, and for various reasons also have and will likely continue to need, a number of Cobalt surface mounted point motors due to the sandwhich construction of part of the layout. These can be operated via DCC or by momentary contact. On-On switches also work but as I understand it over ride any DCC inputs while they are , well, on.

 

It looks as if the NR auxiliary switches will be suitable for switching the servos through the MP controller.

 

regards

[AndyID]

The newest MegaPoints boards remove power to the servos 1 second (IIRC) after they move, so no twitching. Seems to work well.

 

 

This is a common misunderstanding. Somebody, somewhere probably said that and the notion seems to have caught on.

 

According to Megapoints own documentation:

 

"Holding HIGH+MODE will cycle the servo pulse state around the listed modes.

 

1. Pulses always ON.

2. Pulses OFF, signal line low.

3. Pulses OFF, signal line high.** Default mode ** 

 

(Pulses are disabled approx. 500 milliseconds after the servo reaches its set end point.)"

 

 

Disabling the pulses is a lot different from removing power. The servos are still powered on and if there happens to be enough interference to trigger a false input pulse stream the servo can move to some undefined position and stay there.

[Theakerr]

I now have two megapoints controllers and am very happy with them  However, if you are using them on a portable layout it may be appropriate to look at smaller units that are specific to each module as has been pointed out because the connectors can be a bit hard to separate.   For cable extensions I either make my own out of telephone/computer cable when there are a number of signals in one area because this keeps the wiring to a minimum and extensions from Hobby King because they are cheap.   I did not really consider US because living in the GWN the wise ones that guide us have effectively put an import tariff, although they hide it under PC words, on all things US that we try to import making them rather expensive.

Edited April 29, 2018 by Theakerr

[ColHut]

"GWN", you got me there? "Great Wall Nation"?

 

regards

[Theakerr]

Great White North (Canada) although in view of what is happening to the south of us  Great Wall Nation might be something to think about.  BTW, it is still white.

[AndyID]

Great White North (Canada) although in view of what is happening to the south of us  Great Wall Nation might be something to think about.  BTW, it is still white.

 

I prefer FNW. (Frozen Northern Wastelands) 

[Theakerr]

Cant be wastelands with all the stuff in the Ring of Fire.  Now if only the Suits et al could get their act together and stop winging!

[Grinkle]

There is another way

very cheap, no wires (ok a few)

 

mount the controller under the board give it 5v connect the servos job done

I have the hardware it is easily available (I have servos that move)

 

The bit I am short is a pyhon script to get it to do what I want

I would like help with the code from someone who understands python syntax

 

if anyone is interested I will explain

[Grinkle]

I was hoping two things

A: someone would be curious

B: someone would know a child who is doing python at school

 

anyway I charged my camera so I will put up a photo of the system

 

 

[njee20]

Disabling the pulses is a lot different from removing power. The servos are still powered on and if there happens to be enough interference to trigger a false input pulse stream the servo can move to some undefined position and stay there.

Fair enough, I have two older boards and two newer ones. The old ones (with no such functionality) ‘chatter’ quite a lot, the servos don’t move to any perceptible degree, so it’s just annoying, but the new ones don’t at all, they’re silent. I don’t profess to be an expert; remove power, disabling pulses whatever, they’re far quieter in use (or rather not in use) than the older boards.

[Grinkle]

I use one of these to check servos for chatter or overdrive

 

[ColHut]

Thanks All for the input.

 

Interesting to note the dearth of Tam Valley users. Perhaps a feature of there being a local (to the UK) product and the other being in the USA.

 

regards

[Crosland]

Thanks All for the input.

 

Interesting to note the dearth of Tam Valley users. Perhaps a feature of there being a local (to the UK) product and the other being in the USA.

 

Lots of people use the frog juicers and TV products are available from Coastal and Digitrains.