Semaphore signals and DCC

[Roger Sunderland]

Hi there

 I’m looking for some help here please. I operate my signals with GF control boards. These are excellent but rather than use the suggested SPST switch to send an electronic signal to the board to energise the servo to move the arm to off or on, I’m looking for a DCC solution. I currently use JMRI panel pro to operate points etc through Digitrax DS64s.

 The way the boards operate is that when the switch is on the arm is lifted, returning the switch to off and the arm drops back to position. Only requires 2 wires to the board from the switch ie. Current on/signal arm “off”. No current/ signal arm “on”.

 I’ve tried using the DS64 but can’t seem to get it to mimic the simple on/off nature of the SPST switch.

please does anyone have any idea how I can achieve this ?

[Nigelcliffe]

As you say the DS64 doesn't offer this directly, then, simplest I can think of, with no "build your own electronics" would be a Relay on the outputs of the DS64.    The Relay would connect between a turnout output (eg. 1R) and the common positive, and would energise in one direction only of the DS64.    Alternative to the Relay would be a transistor switch (eg. Mosfet module from various online sellers), again energised by one output of the DS64.   

 

There will be accessory devices which do exactly what is required, but I'd usually "build my own" rather than buy a commercial unit.  A decent DCC retailer ought to know what various products do, and the requirement for the GF board is pretty simple - connect two contacts and allow a low current to flow, or release those contacts.   

 

 

 

 

[Stephen Freeman]

depending on whether your DS64 outputs a constant voltage or not, if not you will need a latching relay. Personally I cannot see the advantage of using DCC for the control of signals or turnouts unless you are using such as JMRI panel pro on a PC.

[Roger Sunderland]

Thanks for this Nigel. I will investigate the 2 options you’ve mentioned. As you say , the GF boards have a very simple requirement but I tried DCC Concepts and they said they were unable to help.

[Roger Sunderland]

1 minute ago, Stephen Freeman said:

depending on whether your DS64 outputs a constant voltage or not, if not you will need a latching relay. Personally I cannot see the advantage of using DCC for the control of signals or turnouts unless you are using such as JMRI panel pro on a PC.

Yes I am using Panel Pro on a PC and I’d like to incorporate the signals into that, rather than have a separate panel with switches for just the signals.

[Suzie]

The DS64 will operate four signals but you will have to set it up to operate 'slow motion machines'. Manual for the DS64 is here:-

 

https://www.digitrax.com/media/apps/products/stationary-decoders/ds64/documents/DS64_flattened.pdf

[Nigelcliffe]

48 minutes ago, Stephen Freeman said:

depending on whether your DS64 outputs a constant voltage or not, if not you will need a latching relay. Personally I cannot see the advantage of using DCC for the control of signals or turnouts unless you are using such as JMRI panel pro on a PC.

 

DS64's can be put into "constant output" for devices like tortoise motors.   So a simple relay will do the job.    

 

I agree that DCC throttle handsets are usually awful for controlling signals/turnouts.   However, there are alternative methods including computers (JMRI and other software), or switch panel input devices for various systems. 

 

 

49 minutes ago, Roger Sunderland said:

Thanks for this Nigel. I will investigate the 2 options you’ve mentioned. As you say , the GF boards have a very simple requirement but I tried DCC Concepts and they said they were unable to help.

 

So they don't sell something suitable  (or didn't understand the question).   

 

I'm sure there will be many accessory decoders which will do the job, as they come, out of the packet.    The requirement is electrically very simple;  I think the GF controller will be "switch to ground",  so all the output of the device will require is "output to ground" in one state.    

 

It might even be possible on the DS64 without any additional parts - I don't know how it works, so would need one to measure things.   I'd be looking what happens on the outputs (1R, 1L, etc.) in relation to the decoder's ground (0volts).      If those outputs go to "ground" when inactive, then that may be the solution for the GF inputs.     The use of a relay just ensures that things are correct and isolated.   

 

 

 

 

[Jeremy Cumberland]

My reading of the DS64 manual is that they give a reverse polarity output (positive or negative), either pulsed or continuous. From your description of using an SPST, you want an on/off (positive) continuous output. This might be possible by configuring the DS64 for slow-motion motors as per the manual, and then connecting your signals between nR (or nG) and P+, but this is not mentioned in the manual, and this is rather a fancy controller just to use for on/off outputs. You can connect the two adjacent R or G outputs to the same P+ terminal.

[Roger Sunderland]

The problem with the DS64, in slow motion mode, is that using it for signals, with the GF boards, doesn’t work, I think because you can’t switch off the current. You can raise a signal arm but then you have to remove the power for the arm to return to “on” and the DS64 simply reverses the power, as it would to reverse the point motor if it was connected to one. I’m wondering if I connect the board to  say terminal 1R and the common, leaving out the opposite throw it might work?

 But surely there must be a stationary decoder on the market that can mimic an on/off switch, or be configured to do so.

Nigel, your second guess was right for DCC Concepts- I don’t think they understood the question.

[Steven B]

Train Tech make a DCC accessory decoder with two relays - Train Tech RL1.

 

A slight more involved (but less expensive solution) might be to use an accessory decoder and one of the many relay boards designed for use with Arduinos. These should allow the logic level output of the decode to safely switch the relay as required.

 

Steven B.

[Nigelcliffe]

22 minutes ago, Roger Sunderland said:

The problem with the DS64, in slow motion mode, is that using it for signals, with the GF boards, doesn’t work, I think because you can’t switch off the current. You can raise a signal arm but then you have to remove the power for the arm to return to “on” and the DS64 simply reverses the power, as it would to reverse the point motor if it was connected to one. I’m wondering if I connect the board to  say terminal 1R and the common, leaving out the opposite throw it might work?

 

If you've not tried 1R to Common, then you should.   When you said "didn't work" I assumed you'd tried more combinations.   

Another option if its "half working" would be a series diode in the output, so the accessory decoder is only outputting in one direction. 

 

 

I think its more likely the GF board is looking for a circuit which connects the input to ground (which closing a simple on/off switch over the terminals achieves).   

 

[Roger Sunderland]

40 minutes ago, Nigelcliffe said:

 

 

I think its more likely the GF board is looking for a circuit which connects the input to ground (which closing a simple on/off switch over the terminals achieves).   

 

Yes you are correct in this Nigel, having spoken to GF.

[Nigelcliffe]

1 hour ago, Roger Sunderland said:

Yes you are correct in this Nigel, having spoken to GF.

 

Which brings us back full-circle....

 

Option a)  - costs a little, but definitely works...  Relay (or opto-isolator as switch which is smaller and solid state) on output of the DS64.   This creates a contact which opens/shuts for the GF board.   DS64 configured to operate a Tortoise style motor, so output is continuous.   
Opto-isolator would be very simple DIY electronics with VeroBoard, an Opto-isolator and a resistor.  And probably nothing else needed.    

Option b) - might work, might not....   Keep trying various combinations of outputs/connections on the DS64.  I'd be looking at whether the 1L/1R goes to any of the common connections on the DS64 in one state.   If so, that may be part-way to a no-devices solution.  Additional diode may be useful.   

 

 

[Roger Sunderland]

Thank you so much Nigel. That’s clarified my thoughts and is definitely the way to go. I will try option 2 first to rule it out, if nothing else, although I did try this some years back unsuccessfully, however not with a diode fitted.

[two tone green]

I have the GF  Controls Level Crossing Gate control board which is a slight variation on the signal version and work by grounding one of the connections your switches are connected to.

If you use a jumper from the -ve terminal of your DC power supply for the board to one of the switch terminals the signal will move. take the wire off the signal goes back. Try each switch terminals until you find the right one as you cant damage anything by trying each one. 

Originally I used Digikeijs DR4018 in a stand alone 16 switch output to provide the ground to the relevant terminal on the GF board. I now use the excellent YAMORC YD8116 configured to give me a ground output on one of the channels to provide the ground. 

The terminals are marked 1+2 and so on on the YD8116 and you need either 1 or 2 as the connection to the GF board and NOT + as that is a positive DC output and will cause damage to your GF board.

If you need for info please ask. 

 

 

[Stephen Freeman]

Personally, being a Member of MERG I would use their Steady State Accessory decoder to switch a suitable relay to effectively simulate a simple On/Off switch. If I wanted to use Panel Pro. I wouldn't consider just using the DCC controller, that's for driving trains in my book.

[Roger Sunderland]

Thanks both of you for the further suggestions. My friend is currently looking at possible MERG alternatives as he’s a member. The Yamorc option does sound interesting though. If I may I’ll come back to you on this if necessary.

[Nigelcliffe]

10 hours ago, Roger Sunderland said:

Thanks both of you for the further suggestions. My friend is currently looking at possible MERG alternatives as he’s a member. The Yamorc option does sound interesting though. If I may I’ll come back to you on this if necessary.

 

The MERG steady-state decoder can be assembled to do the "switch to ground" for the GF signals directly.  No additional parts required.  One MERG unit would control eight GF signal devices.   The combination of the assembly instructions AND the technical notes for the steady-state decoder will cover the build option required - ie. don't just plough through populating everything following only the build instructions; some parts in the kit not required and will need "wire links" in place of them.  

 

( I thought the requirement was to work from existing DS64's).  

 

- Nigel

[Roger Sunderland]

Thanks Nigel, I’ll bear that in mind. I would probably prefer to use the DS64 as I already have them but I’ll look at all options.

[two tone green]

18 hours ago, Roger Sunderland said:

Thanks both of you for the further suggestions. My friend is currently looking at possible MERG alternatives as he’s a member. The Yamorc option does sound interesting though. If I may I’ll come back to you on this if necessary.

One excellent feature of the YD8116 is that it’s capable of controlling lots of different items such as signals, point motors and act as off on switches. Each output is individually configurable using a simple graphical interface so you can have points, signals whatever all controlled from one box. For example your signal on output 1 and a point on output 3&4 and a multi aspect signal on other outputs so no outputs are wasted.