Wiring for auto point working

[ozzyo]

Hello all,

 

as the title says I'm after a wiring diagram to auto work two point motors, as in the drawing below.

 

I have a Gaugemaster CDU to fit in the circuit as seen below,

 

The controller that I have is a Gaugemaster 100M, with both? 12vDC and 16vAC uncontrolled.

 

 

The point in question is a double slip in the middle of my test track, that is worked by an auto shuttle unit. That is worked by R/S and magnets

 

The idea of the unit is that the loco will start at S then move off to 2 opening or closing R/S1 throwing point motor A, then setting back to 3 (but it must not work R/S1 a second time), as it goes over R/S2 this works point motor B, then the loco sets off to 4 as it goes over R/S3 this works point motor A, then the loco sets off to S, operating R/S4 that works point motor B. The part that gets me is the loco has to go over all of the R/S twice but it only has to work the point motor once.

 

What I would like is a simple (I'm a complete numpty when it comes to electrics) circuit drawing and parts list to be able to make it. For the circuit base I'll be using Vero? board and for the parts Maplins. I would also like a on off switch in the power input, I'm thinking of a D/P on off switch for this, as I may need to run the loco over one of the routes more than once.

 

The switches for the frog polarity are in place and working well.

 

Thanks for any help as I WILL need it

 

TFAH

 

OzzyO.

 

 

[Ray H]

Are you saying that you have an auto shuttle system working? Does that system (if you have it) use reed switches?

 

Presumably shuttle systems stop and start the "loco" reasonably abruptly. As a result the loco will probably come to rest over the reed switch so the loco will approach the reed switch, activate it, stop and de-activate the reed switch as it moves away.

[ozzyo]

Are you saying that you have an auto shuttle system working? Does that system (if you have it) use reed switches?

 

Presumably shuttle systems stop and start the "loco" reasonably abruptly. As a result the loco will probably come to rest over the reed switch so the loco will approach the reed switch, activate it, stop and de-activate the reed switch as it moves away.

 

Hello RayH,

 

I do have an auto shuttle system in use, and it uses reed switches, but it has a slow stop feature and a delay that can be used. So the loco and magnet don't stop over the R/S but pass over it and have to pass over it a second time when it reverses.

I don't want to use the same R/S for the point motors.

 

OzzyO.

[Ray H]

Sorry for the questions but . . .

 

Does the loco stop reasonably accurately at the same place each time and how long is it stationary for?

 

I wonder if you can position the additional reed switches accurately enough so that they're only activated briefly and rely on the fact that you're using a CDU to fire the points. The loco slows to a stop at the "new" reed switch and that triggers the CDU to change the point. A miniature micro switch with a lever on it that is moved by the tie-bar could then isolate the connection to the CDU once the point has changed as a safeguard in case the loco doesn't reverse.

[ozzyo]

Sorry for the questions but . . .

 

Does the loco stop reasonably accurately at the same place each time and how long is it stationary for?

 

I wonder if you can position the additional reed switches accurately enough so that they're only activated briefly and rely on the fact that you're using a CDU to fire the points. The loco slows to a stop at the "new" reed switch and that triggers the CDU to change the point. A miniature micro switch with a lever on it that is moved by the tie-bar could then isolate the connection to the CDU once the point has changed as a safeguard in case the loco doesn't reverse.

 

 

Hello Ray,

 

I don't want to rely on the loco/magnet stopping in the same place. As it's a test track I would expect the loco to start running freer after a bit of running so it's stopping place would move. The length of time the loco/magnet stops can be adjusted from 0 to about 60 sec. or more, I tend to have about 2 sec. delay so I can get as much running as poss. in the time that it's running.

What I'm after is the loco/magnet passing over the reed switch and firing the point motor but not firing them when it reverses (the second pass).

If it had been as simple as wiring the CDU through the reed switch I could have done that, but I don't think that the reed switches would have lasted a long time and I would have had the problem of the reed switch trying to fire the CDU a second time.

So I'm thinking about 2 or 3v going through the reed switch and that pulse firing the CDU .

 

If the loco/magnet only pasted over the reed switch once it should have been a simple circuit with a thing (see I told you that I'm a numpty with electrics) that cuts down the voltage going to the reed switch.

 

HTH

 

OzzyO.

[Gordon H]

The most effective way with this technique is to create an arrangement which knows which reed switch is to be responded to next, and only connect that one switch through to your point firing device each time.

This could be achieved with latching relays or something similar - essentially you need a system which has a simple memory.

Which particular auto shuttle are you using?

[Simond]

Hi Ozzy

 

Just to make sure I have this right, you want to go around all four legs in zig-zag fashion - your numbering scheme is "interesting"

 

So, starting at "S", bottom left, point motor PM "B" is "up", loco goes across switch RS 4, (presumably PM A is already "down") then RS 1 and arrives at leg 2, top right.

 

Shuttle reverses loco. RS1 sets PM A to "up". Loco crosses RS1 again (might set PM A to "up" again, doesn't matter) and goes to leg 3 crossing RS 2.

 

Shuttle reverses again. RS2 sets PM B to "down" Loco crosses RS2 again (as above) and goes to leg 4, crossing RS3.

 

Shuttle reverses again, RS3 sets PM A to "up", loco crosses RS3 again, and goes to leg S, crossing RS4 as it does so, which switches PM B to "up", ready to start the process again.

 

If this is right, you will see that there are 4 switches and 2 motors each with 2 coils. I can't draw the schematic now, but will do it later, but I can describe it;

 

On the Gaugemaster diagram, there is one wire from the CDU to the common connection of two coils A & B, and one wire to two switches (but they are drawn as if in one box).

 

These two switches can be two reed switches, for example RS4 and RS2, and that would switch PM B "up" & "down" respectively.

 

Copy the circuit again, with switches RS1 & RS3 and connect these to PM A "up" & "down" respectively.

 

This will work, and as long as the slips will trail a loco without derailing when it's set wrongly, it will sort itself out wherever you put the loco on, and whichever way it starts too. You need some wire and solder, no Vero, and no extra components!

 

One thing though, it won't go "the other way round, unless you want to add a degree of complexity - a multi-pole switch and a lot of extra wires!!!

 

I'll do the diagram tomorrow & post it.

Best

Simon

[ozzyo]

Hi Ozzy

 

Just to make sure I have this right, you want to go around all four legs in zig-zag fashion - your numbering scheme is "interesting"

 

So, starting at "S", bottom left, point motor PM "B" is "up", loco goes across switch RS 4, (presumably PM A is already "down") then RS 1 and arrives at leg 2, top right.

 

Shuttle reverses loco. RS1 sets PM A to "up". Loco crosses RS1 again (might set PM A to "up" again, doesn't matter) and goes to leg 3 crossing RS 2.

 

Shuttle reverses again. RS2 sets PM B to "down" Loco crosses RS2 again (as above) and goes to leg 4, crossing RS3.

 

Shuttle reverses again, RS3 sets PM A to "up", loco crosses RS3 again, and goes to leg S, crossing RS4 as it does so, which switches PM B to "up", ready to start the process again.

 

If this is right, you will see that there are 4 switches and 2 motors each with 2 coils. I can't draw the schematic now, but will do it later, but I can describe it;

 

On the Gaugemaster diagram, there is one wire from the CDU to the common connection of two coils A & B, and one wire to two switches (but they are drawn as if in one box).

 

These two switches can be two reed switches, for example RS4 and RS2, and that would switch PM B "up" & "down" respectively.

 

Copy the circuit again, with switches RS1 & RS3 and connect these to PM A "up" & "down" respectively.

 

This will work, and as long as the slips will trail a loco without derailing when it's set wrongly, it will sort itself out wherever you put the loco on, and whichever way it starts too. You need some wire and solder, no Vero, and no extra components!

 

One thing though, it won't go "the other way round, unless you want to add a degree of complexity - a multi-pole switch and a lot of extra wires!!!

 

I'll do the diagram tomorrow & post it.

Best

Simon

The slip (points) are Peco type so the loco can't bash the blades over. I have drawn it to show one way of running it could also go S-4 [pm A throws, by R/S 3) -3 [pm B throws, by R/S 2] -2 [pm A throws, by R/S 1 ] - S [pm B throws, by R/S4] then back to 4.

 

I'd like to suggest a CMOS 4017 counter with 1-of-10 outputs. Each R/S is connected to a particular output (0-3) with the next output (4) connected to the reset pin of the chip. The common of the R/S's then connects to the clock input, making sure the R/S operates only once. The same outputs of the 4017 chip also control a diode matrix that in turn, using power transistors, fire the coils of the point actuators. Diagram on request (I'm not making it if there's no interest )

 

As I said in my first post I'm a complete numpty when it comes to electrics, so to say a CMOS 4017 counter with Etc. it goes over my head. If it will do what I want it to do please show me a drawing and the parts that I will need to make the circuit board. I maybe the only person that may want this type of circuit so the chance of getting a lot of interest is limited.

 

TFAH

 

OzzyO. 

[Simond]

Ozzy

 

try this. It will switch each point twice, as the loco goes over the reed switch one way and then the other, but as the switching is in the same direction, it doesn't matter.

 

re the trailing point thing - if the blades are locked, then you need to put the loco on in the right place, so your start position, with the blades set correctly for the first move.  thereafter it will be fine.

 

It could be wired to run the other way around - just as simply - but getting it to do both requires more effort.

 

best

Simon

 

 

[Gordon H]

OK, here's the diagram:

reedswitch_sequencer.jpeg

How does it work:

The 7812 chip is a voltage regulator and must come with a big capacitor. That's because the circuit only uses a single diode to rectify the AC input. When the power is applied, a small capacitor resets the circuit so only the top output of the 4017 chip (pin 3) is active. The loco traverses the layout and actuates the first R/S. Via the diode and said R/S the clock input (pin 14) will increase the internal counter and the second output will become active (pin 2). At the same time pin 3 will become inactive and therefore, so does the first R/S. Again, the loco traverses the layout and actuates the 2nd R/S. Via the diode and this R/S the clock input (pin 14) gets another pulse, the counter increases again and pin 2 becomes inactive, while the next output (pin 4) is now active. Loco travels again, operating the next R/S in the sequence and pin 7 now becomes active, while pins 2, 3 and 4 are inactive. The loco travels again and operates the last R/S of the sequence. But now 2 things happen almost simultaneously: as pin 10, the next pin in the counter sequence, becomes active, it resets the counter via the reset input (pin 15). So now pin 3 is active and the circle is round.

 

At the same time as each output pin becomes active, it sends a signal to the corresponding transistor. This transistor then operates a diode matrix that controls the coils of the double slip. You'll notice there are some resistors and capacitors in that part of the circuit. In order for the CDU to fire properly, it needs to charge itself. It can only do so if there's no current drawn from it. The capacitors make sure that the transistor only gets a small pulse and is otherwise forced to open its output and thus no further current can flow. This allows the CDU to recharge itself. You may need to experiment with the value of these capacitors to ensure the coils operate reliably.

 

Pin 16 is the power supply for the 4017 chip, pin 8 is the negative for that. Pin 13 is an input pin that requires power for the chip to work. By connecting pin 13 to pin 8 you disable the entire circuit. (i.e. switched off) Other pins (not named) are unused outputs and don't need any connection at all.

 

Any questions, feel free to ask!

 

PS: it's not one of the most tidiest circuits I've drawn, but it's late

 

A couple of things to mention about the circuit diagram as currently shown...

The electrolytic capacitor around the input of the 7812 is shown upside down relative to the normal convention.

The 100nF discharge timing capacitors are likely to need beefing up a bit. Based on experience with similar circuits driving solenoid motors, I would suggest 10uF or 22uF for these (35V working or upwards). You could probably get away with smaller capacitor values by using power MOSFETs instead of the Bipolar BD135s, but the overall price difference is likely to be minimal.

Otherwise, it looks more or less like the sort of thing I suggested, where the 4017 creates a kind of memory device in the form of a decoded counter.

[megabodger]

Be wary of the circuit with reed switches. It's VERY unusual for reed switches to have the current carrying capability to allow them to fire solenoid point motors.

 

The way round this is to use the reed switches to control relays, which should be chosen (1) to have the current carrying capability to fire the point motors (say 5 amp contacts)  (2) to not draw eneough current through the relay coil to knacker the reed switch, which are rarely capable of passing more that 1/4 to 1/2 Amp.

 

Sorry - I cant draw a diagram just now.  It's now Monday lunch time.  Today, I'm on the 1408 to Cheltenham Spa, coming back on Wednesday evening. Thursday, I'm on a day  trip to Manchester and Friday, I pick up the hired van and take Pen-y-Madoc to the Leamington & Warwich Show.........

[Simond]

it is true that solenoid motors require high currents and reed switches are not designed for them, however, I proposed the simple solution above based on the "make" being more stressful (but much less damaging) than the "break" which should be nearly zero current, and I would expect it to work for an appreciable period - I would not like to guess how long - before contact degradation requires replacement of the reed switches

 

addition of relays is easy, but I'd only suggest it if the circuit as drawn doesn't last

 

best

Simon

[ozzyo]

Hello all,

This has been a bit of a long term job as the Pway and S&T departments have not been able to decide who should do the job. The S&T say that it should be them as it's a power signal box, the Pway department say that it should be them as it involves them. Anyway after a twelve month dispute they have started work on the new power box.
The first job was to lay in the new power cable (the white one) to the switch box,


Then onto the foundations for the power box, you can see the piles that had to put in to support the weight of the box, you can see the old track bed in this photo. The Pway department did the job a couple of years ago with no problems as this slip was worked by the old manual box,


The line manager came down to see how work was progressing, he was not that happy to see all of the spoil and the land slip on the line. As this is the junction between four intensively used main lines,

At the moment all of the services are have to use the two old lines, at some times they have to use "bang" line running,

But they did manage to get the gauging train loco down (but not the test train), this is a shot of it heading back to its home shed,


The interior of the new power box. Due to delays in the supply of parts (a four way screw terminal that will fit where the blue line is) this can not be fitted just yet, the high power unit is installed on it base outside of the power box as can be seen in some of the photos,

The next job will be to fit the A.T.C. sensors between the running rails, there has been a long discussion between the S&T department and the C.M.E. as to the location for the track sensors and the pick-up gear on the locos, this is still on going.

OzzyO.

 

PS. thank to all who have replied to this topic. I did decide to use relays to fire the point motors after having a chat with a mate of mine over a pint.

But thanks again to all.

[Simond]

Ozzy

 

I think the relays are a good idea, they'll add to the life of the reed switches without doubt, but of course, at the cost of added complexity.

 

Do post up a schematic

 

Best

Simon

[ozzyo]

Hello all,

 

the S&T department have now down tools and have put in a complaint that the work is to complex for them as it involves more than three wires.

 

So the General Manager came down again to have a look!

 

He has now decided to open a new department, the electric engineering department (to be know as EEgD). This department has now done an electrical drawing for the work involved. The outside of the power box is in green along with the high power room. Any under floor wiring is now in red with the above floor conduits in black. Any of the outdoor power supplies are in different colours depending on their work load.

 

OzzyO. 

[Simond]

Ozzy

 

This looks like it will work ok, but two points (sorry..) if I may

 

You have a gold "X" on the central wire from the CDU output to the motors - you need this wire.

 

You have a black line which appears to go between the output and input of the CDU. Don't connect input & output - likely to cause it to let the smoke out of something...

 

Do keep us informed!

 

Cheers

Simon

[ozzyo]

Ozzy

 

This looks like it will work ok, but two points (sorry..) if I may

 

You have a gold "X" on the central wire from the CDU output to the motors - you need this wire.

 

You have a black line which appears to go between the output and input of the CDU. Don't connect input & output - likely to cause it to let the smoke out of something...

 

Do keep us informed!

 

Cheers

Simon

 

Hello Simon,

 

the gold X on the centre wire is to remind me that I have still to fit it as I don't have the connectors for the return from the point motors. I've decided to use a 4 way connector for this. So if I have to remove any parts it's just a matter of unscrewing some wires and then the board or the motors Etc. can be renewed.

 

Not shown on the drawing is a 4PDT switch on the 12 and 16 volts supplies. So that I can switch out the power box and only run one route if I find that a loco is having a problem with route say 4-1. Then that can be lock in and the loco tested until the problem is sorted out. I do know that it may take a few runs until the CDU has discharged all its power.

 

It may appear that the black line goes between the output and input of the CDU, but there are two red leads that run close together,it's all down to my bad drawing. If you look at the bottom input feed to the CDU it has a dog leg in it, then the top output just comes out in a straight line. The two don't connect.   

 

Thanks for the input,

 

OzzyO.

[ozzyo]

Hello all,

not a lot to report on the new power box due to all of the EEgD taking Sat. and Sun. off to watch the rugby and only two of them turned in for work today, Tommy and Taff, with no sign of Paddy and Jock. But they did get the new sensors in for the A.T.C. along with the new wiring,

They did get the power box onto it base to check the wires and found them all over length, this will have to come out again as one of the connectors has not turned up,

But a start has been made on cutting all the wires back to an approx. length. Whether Tommy and Taff will be in work tomorrow is any ones guess as they were last seen heading off to the scrapyard with all of the excess copper wire,

OzzyO.

[ozzyo]

Put the images online, we can't see what you got stored locally (and be glad we can't )

 

Er what images?????????????????????

[ozzyo]

These images:

 

001-0-022-jpg.41928

 

001-0-025-jpg.41930

 

001-0-027-jpg.41931

 

I omitted the text in between.

 

The photos were there when I checked them but when I had a look on the other puter they were not there? I've now put them back in the post. I hope!

 

OzzyO.

[ozzyo]

Hello all,

 

well we had the full gang back today and some work got done. the EEgD had a good look at the drawing  and deicide where the last connector had to be fitted, that was after a lot of head scratching. As the drawing did not fit the base of the power box,

 

After a bit of digging by Paddy the base and all the connections were in place,

 

I would like to thank all of the staff that have worked on this job as it is now up and running. Without some of the input from the outside contractors we would not have had a chance of building the new power box.

 

  Paddy, Said to me today "I'm not diggin them foundatioons  that close to the fokking railway lines".

 

OzzyO

 

 

PS. I have tested it and it works. A big smile, from me and all of the gang.