Templot Club Archive 2007-2020                             

topic: 3116MERG CBUS system
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posted: 24 Oct 2017 12:55

from:

FraserSmith
 
Dundee - United Kingdom

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This topic is to complement the MERG DCC topic and be a place where the CBUS system can be discussed. CBUS has been developed by members of MERG to provide a means to connect control panels with devices detecting occupancy, operating points, signals, water columns, level crossings etc etc via just 2 wires carrying messages and two wires providing a 12Vsupply to power those devices.

For a control panel one or more CANPANEL modules can be used. Each module can monitor 64 switches and drive 64 LEDs but only need 4 wires to connect the panel to the rest of the layout.

For operating servos to change points you can use a CANMIO-SVO that can drive 8 servos to give realistic switch blade movement and also monitor 8 inputs to detect block occupancy or switch blade position using micro switches on the MERG 3D printed servo mount. Additional micro switches can be used on the servo mount to change the crossing polarity as the switches move so eliminating the need for techy frog juicers. Because the units can be placed close to the points being driven there is little need of long servo cables and extensions. Many of these modules are in use on Pete Waterman's Leamington Spa layout.

For those who still want to subject their trackwork to punishment from solenoids there is a CANCDU that can change 4 points and monitor 6 inputs.

This is just a flavour of what can be done. If you have questions please raise them here and one of the at least three MERG members that use this forum will surely reply.

Fraser


posted: 24 Oct 2017 19:42

from:

Rob Manchester
 
Manchester - United Kingdom

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Hi Fraser,

Good idea to start this thread. Is the CANMIO-SVO module available now ? According to the list of kits etc on the MERG site it is 'COMING SOON'. I don't have access to the members areas yet as I wanted to make sure that everything I may want is actually available before joining. I assume you mean kit number 98 ? It mentions options - what are they ?

Rob


posted: 24 Oct 2017 21:13

from:

Ian Hart
 
United Kingdom

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The CANMIO-SVO kit is not yet available.
The CANMIO is a multi-functional board. It can be built for various purposes and sub-boards can be added to provide additional functionality. It can be an input module (feedback from points, block detectors,etc , an output module (LED and or Relay drive) or Servo driver.

You can buy the CANMIO PCB from MERG and source the components yourself.

Kits can go out of stock and sometimes you have to be patient for the restocking.  All of which is done by MERG members in their spare time.

Kind regards,
Ian H (Another MERG Member)
Last edited on 24 Oct 2017 21:23 by Ian Hart
posted: 24 Oct 2017 21:40

from:

Rob Manchester
 
Manchester - United Kingdom

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Ian Hart wrote:
The CANMIO-SVO kit is not yet available.
The CANMIO is a multi-functional board. It can be built for various purposes and sub-boards can be added to provide additional functionality. It can be an input module (feedback from points, block detectors,etc , an output module (LED and or Relay drive) or Servo driver.

You can buy the CANMIO PCB from MERG and source the components yourself.

Kits can go out of stock and sometimes you have to be patient for the restocking.  All of which is done by MERG members in their spare time.

Kind regards,
Ian H (Another MERG Member)
Hi Ian,

Thanks for coming in on the thread.We are getting to know the MERG people within Templot now.

At this stage I am only thinking along the lines of using servocs to control turnouts, level crossing gates and semaphore signals. I am not ( as yet ) interested in interlocking, occupancy detection or feedback to a computer so would just require a kit ( or PCB and component list ) to enable servos to be actuated via a DCC system.

I think I should join MERG now rather than waiting, it isn't expensive, and at least I can get access to the tech info and figures out what each module is capable of.

I can then start to join the queues at Maplin for some bits :D

Rob


posted: 24 Oct 2017 23:02

from:

Charles Orr
 
Leicester - United Kingdom

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Rob,
You will find that Rapid Electronics, Farnell or RS Components will be much cheaper than Maplin.

Regards

Charles



posted: 24 Oct 2017 23:07

from:

Charles Orr
 
Leicester - United Kingdom

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I should add that Mouser and Digikey in the UK are also options.
You need to shop around.  :)

posted: 24 Oct 2017 23:21

from:

Rob Manchester
 
Manchester - United Kingdom

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Charles Orr wrote:
I should add that Mouser and Digikey in the UK are also options.
You need to shop around.  :)
Hi Charles,
Thanks for the hints. Yes, I just used Maplin's as an example that everybody would have heard of. I have spent a lot of time ordering electronics and computer components in my working life. I can even remember buying kits, modules and parts from Radio Shack/Tandy when they used to have a store in every town !

Good news, although maybe not for the rest of you. I just joined MERG :roll:

Rob


posted: 24 Oct 2017 23:26

from:

Charles Orr
 
Leicester - United Kingdom

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Rob,

That's good to hear.

I'll watch out for your posts.  :)

Regards

Charles

posted: 25 Oct 2017 07:11

from:

FraserSmith
 
Dundee - United Kingdom

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Hi Rob

As a MERG member now you will obviously have signed up for and read the latest forum digest in which there was a post explaining about DCC and CBUS busses and why you need both but then again you may not have got that far just yet!! I was going to write something similar in response to your comment above about operating servos via DCC but I think this posting says it all.

"I'll try for a brief summary:

Both DCC and CBUS are 'buses'. A bus is a communications channel which allow a number of 'things' to attach to a common pair of wires, such that every 'thing' on the bus receives every message sent to the bus and then decides which ones to act upon. It means we no longer have gazillions of wires running around the layout from the control panel and throttles.

In the case of DCC, the bus is generally the two rails and the 'things' are usually locos with a decoder chip. DCC also allows for accessory decoders to be attached to the same bus.

CBUS is a layout control bus (LCB), designed for controlling everything but locos (except that messages between the MERG DCC command station and handsets are CBUS messages on a CBUS).

Why would you need CBUS if you already have an investment in DCC ? Isn't it just additional complexity, cost and wires ?

Two main reasons:
    DCC has no standard capability for accessories to send messages back to the command station, other than various commercial offerings. That means no sensors or feedback from the layout to the control panel or computer unless you buy a product. Has that point actually moved fully ? There is no easy way of telling with basic DCC.
    if a loco shorts the two rails and trips the command station, you lose control of your locos and accessories, e.g. if the problem loco is straddling a set of points, you have no control over either the loco or the points. Unless you run a separately-powered DCC accessory bus.
So, unless your needs are very basic, there's no way to avoid the complexity and two physical buses. At least with MERG designs you can keep the cost and complexity down and not get locked in to a single manufacturer's products."

Second point is regarding the MIO-SVO. It is not a kit just yet but that is only due to the dotting the "i"s and crossing the "t"s on the various bits of documentation to support it. The most recent versions of the build instructions and details on using it are available on the wiki and Pete Brownlow, the developer of this module, will supply a "bag of bits" if requested.  Search for CANMIO on the wiki. £30 minimum order for free postage from Rapid if you buy your own bits. Radio Spares is all postage free but the components generally cost more.

Enjoy the ride to come.

Fraser

posted: 25 Oct 2017 15:29

from:

d827kelly
 
Coventry - United Kingdom

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Another MERG member here. I've built a couple of CBUS modules and just finished (with some help) a CANCMD module (still needs to be tested though).

I am awaiting the CANMIO boards becoming available as kits before going further at present as I'll need a few for the current layout plans.

posted: 25 Oct 2017 16:40

from:

FraserSmith
 
Dundee - United Kingdom

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Hi d827kelly

As I noted above Pete will supply bags of bits for the MIO at what I'm sure will be a very similar price to the kit when it comes. All the instructions are on the wiki and the boards are available from the kitlocker. What's stopping you?

Seriously if you have built the CANCMD, even if you did have help, then building the MIO won't be any more difficult. Email pete and ask about the bag of bits and check what version of the firmware will be on the chip so that you will know what to use to set it up. The only problem I had when building was keeping the 3 pin headers for the servo connections upright. I would recommend only soldering one pin of each first and checking alignment before soldering the other two. A big blob of Blutack is quite useful in holding them in place but ideally not on the pin you will solder first. It's a great bit of kit and with the latest version of the firmware and Ian Hogg's new setting software it will be hard to beat.

Cheers

Fraser

posted: 26 Oct 2017 00:12

from:

Rob Manchester
 
Manchester - United Kingdom

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Hi Fraser,

Thank you very much for your detailed post earlier, the information is much appreciated and certainly makes sense. The little layout I am currently wiring up will just have a MERG DCC Steady State Decoder added to the DCC track bus as I just need to get it up and running ASAP.

I will certainly bear you thoughts in mind on my other layout plans ( planned in EM, O/31.5, US HO and On30 ).

Rob


posted: 26 Oct 2017 01:35

from:

d827kelly
 
Coventry - United Kingdom

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FraserSmith wrote:
Hi d827kelly

As I noted above Pete will supply bags of bits for the MIO at what I'm sure will be a very similar price to the kit when it comes. All the instructions are on the wiki and the boards are available from the kitlocker. What's stopping you?

Seriously if you have built the CANCMD, even if you did have help, then building the MIO won't be any more difficult. Email pete and ask about the bag of bits and check what version of the firmware will be on the chip so that you will know what to use to set it up. The only problem I had when building was keeping the 3 pin headers for the servo connections upright. I would recommend only soldering one pin of each first and checking alignment before soldering the other two. A big blob of Blutack is quite useful in holding them in place but ideally not on the pin you will solder first. It's a great bit of kit and with the latest version of the firmware and Ian Hogg's new setting software it will be hard to beat.

Cheers

Fraser


Fraser,

Until it was mentioned above (which I didn't see until after I'd posted my first post) I wasn't aware that Pete was doing bag-o-bits as I'd thought it was just the PCBs.

Funds don't allow for ordering anything atm though due to car mot being due this month.

Kelly

posted: 26 Oct 2017 09:35

from:

Judi R
 
Sutton-on-Sea - United Kingdom

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Pete has been supplying bags-o-bits for a while and the PCBs are available in the Kit Locker. We are working on a full kit and I'm hoping that it might be available by the end of the year.

posted: 28 Oct 2017 20:02

from:

Richard Spratt
 
Stockton-upon-Tees - United Kingdom

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Is CANMIO-SVO an update of CANSERVO8 ? I have several CANSERVO8s but I'm not entirely happy with them. They have a tendency for the servos to twitter, sometimes randomly, sometimes caused by a loco running past. Not very good when it's the servo that controls the point the loco is running over! I did ask for help on the forum but got nowhere having multiple potential solutions offered

posted: 28 Oct 2017 21:07

from:

Andrew Barrowman
 
USA

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Richard Spratt wrote:
Is CANMIO-SVO an update of CANSERVO8 ? I have several CANSERVO8s but I'm not entirely happy with them. They have a tendency for the servos to twitter, sometimes randomly, sometimes caused by a loco running past. Not very good when it's the servo that controls the point the loco is running over! I did ask for help on the forum but got nowhere having multiple potential solutions offered
Hi Richard,

The problem isn't so much with the controllers; it's the servos themselves that are very good at responding to any sort of interference. Typical radio-control applications don't produce much interference energy, but model railways can produce a lot, sometimes an awful lot.

One way to solve the problem is to optically isolate the signal between the controller and the servo like this:

2983_281542_290000000.png2983_281542_290000000.png

This version uses a 4N25 opto-isolator and a couple of resistors. It's not expensive. I've tested it with a 30 foot long twisted pair connection and some extremely aggressive electrical noise generators. The tests were 100% successful.

I don't know if MERG provides something similar. They might want to consider it if they don't.

Regards,
ab

posted: 28 Oct 2017 21:42

from:

d827kelly
 
Coventry - United Kingdom

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Richard Spratt wrote:
Is CANMIO-SVO an update of CANSERVO8 ? I have several CANSERVO8s but I'm not entirely happy with them. They have a tendency for the servos to twitter, sometimes randomly, sometimes caused by a loco running past. Not very good when it's the servo that controls the point the loco is running over! I did ask for help on the forum but got nowhere having multiple potential solutions offered

Canmio is an attempt to redesign several modules to use a common PCB design and different firmware on the pic to provide functions.

So yes, it is a servo8 on a new PCB, with similar firmware (others on the merg furum can put it much better than me though).
[size=
]
[size=The twittery servos I've understood to be a combination of factors, with interference one such example, twisting the wires to take out crosstalk is one solution iirc as is the type and quality of the servo. ]

posted: 29 Oct 2017 15:37

from:

FraserSmith
 
Dundee - United Kingdom

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Hi Richard

Do you have long servo leads radiating out from your Servo 4? If so that could be a big part of the problem. Alternatively if your leads are plenty long enough then how you absorb the excess is quite important. If you roll them up into a nice tidy loop then you have made a coil to pick up all sorts of interference. The best plan then is to get somewhere near the middle and pinch the cable to double it back on itself and then coil that doubled section up. The the interference created in the turns in one direction will be cancelled out by the turns in the opposite direction. The alternative is to site a driver adjacent to each servo and drive it via twisted pair from a CANACC8 or MIO OUT. There is a Servo1 board for SM components and I updated Davy Dick's EzyRemote with a PCB to create an EzyRemotePCB that can have a relay fitted to switch the common crossing. It can be adjusted using a remote box that gets plugged into the board so you can see the points as you twiddle the knobs. Details of both on the wiki.

Fraser

posted: 29 Oct 2017 18:33

from:

FraserSmith
 
Dundee - United Kingdom

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Hi Andrew

That's a very neat trick with your circuit. I've not seen anything like that suggested in the two and a half years I've been a member of MERG. As I noted above I've gone for a different solution but it does share the length of twisted pair wire!!

Cheers

Fraser
Attachment: attach_2552_3116_EzyRemotePCB.jpg     436
Last edited on 29 Oct 2017 18:33 by FraserSmith


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