FAQ - How do I synchronise the passing loop point position indicators in RailMaster?

[Chrissaf]

A solution to this question was originally posted by Ray [forum member St1ngr4y]. Ray’s posted answer has unfortunately been lost in the transfer of the old forum to the new one. This FAQ tutorial is a joint collaboration between Ray and I to recreate his original documented solution but with significant embellishments in the level of detail.

Issue Description.

Before jumping straight into solution mode, it is worthwhile documenting why ‘passing loops’ have been problematic to support in RailMaster.

What is a ‘passing loop’? – For the purpose of this tutorial a ‘passing loop’ is created between two opposing points via two alternative track routes – see image below:

In terms of using ‘passing loop’ functionally, both points need to be switched together to form one of two routes, either a route via the upper track or a route via the lower track. In order to save using two different ‘Accessory Decoder’ ports, most users prefer to wire the two point motors in parallel to a single ‘Accessory Decoder’ port which means using a single DCC Address for that port.

Or alternatively if ‘Accessory Decoder’ port available capacity is not an issue, each point can be wired to a dedicated ‘Accessory Decoder’ port with either the same or different DCC Addresses.

Given these three possible implementation choices:

1. Two points wired to same port with single DCC address.
2. Two points wired to a pair of ports but both ports using same DCC address.
3. Two points wired to a pair of ports with different DCC Addresses.

The only one that will work when using RailMaster ‘Standard Edition’ is the third option where two ‘Accessory Decoder’ ports are used, each with a different address. This means however that each point needs to be selected and operated as two different operation tasks. That is to say, switch one point first to the required route, then the other one to the same required route. This will result with the ‘point position indicators’ showing the selected route correctly.

So the question is – why do options 1&2 above using a single DCC Address result with the ‘point position indicators’ becoming out of synchronisation with the actual physical point position.

This is because with these two options you are only using a single DCC Address to represent both points. In DCC, when you send an operate command to an Accessory Decoder. The command specifically gives the command ‘switch left’ or switch right’ as part of the DCC command protocol structure.

In the RailMaster application software it is this DCC command ‘switch left’ & switch right’ that is being used to control and define which way the blue point position indicator is displayed.

Thus when using a single DCC Address for both points, both RailMaster track plan point icons are responding to the same ‘left or right’ DCC command. Therefore when we apply this same ‘left or right’ point switching DCC command concept to the ‘passing loop’ layout design we get the following:

We can now see that because a single point address is being used for both points, then both point indicators have to comply with the ‘switch left’ or ‘switch right’ DCC command and display their point route position accordingly which can never result with both indicators pointing together into the same route.

Therefore it is not possible to synchronise the point position indicators for a ‘passing loop’ design when using a single DCC Address.

Note that no matter what you try, you cannot correct this by reversing the wires on the point motor(s) NOR using the ‘Reverse Polarity’ checkbox on the point configuration dialogue box. This is because the ‘blue line’ indicator position is controlled by the DCC command and there is no configurable option in RailMaster to tell the blue line indicator to indicate a ‘switch right’ position when a DCC ‘switch left’ command has been triggered and vice-versa for the other point switched direction.

In order for the two point position indicators to display the correct route, one point must switch left whilst the other point has to switch right. This is demonstrated in the next pair of images.

Passing loop - RailMaster ‘Standard Edition’ solution options.

In RailMaster ‘Standard Edition’ the only way this can be achieved is as previously stated, in that two different physical ‘Accessory Decoder’ ports must be used, each with a different DCC Address. Both points then have to be operated separately as two distinct separate operation tasks. One point is switched ‘Left’ whilst the other point in the pair is switched ’Right’.

It might be possible in RailMaster ‘Standard Edition’ to use the RailMaster ‘Routes’ function to set these paths or create a ‘Program’, but to do so is likely to involve more button pressing than just biting the bullet and operating the two points using two separate mouse clicks on their respective point Red and Green buttons.

In this alternative ‘Standard Edition’ solution below, the point on the right is not assigned any operating control buttons or given a DCC Address. The right point motor is then wired in parallel to the point motor on the left which is given a DCC Address and operating buttons. The left hand ‘blue line’ point position indicator then gives enough ‘non-conflicting’ display information on its own to show the selected route i.e. the upper or lower track route. Not ideal, but a reasonable workaround to get round only using one set of Red & Green control buttons and one ‘Accessory Decoder’ port for both point motors. See image below:

Passing Loop - RailMaster ProPack Solution.

However, in RailMaster Pro, there is a ProPack specific feature available that can really simplify this ‘passing loop’ operation and allow it to be supported using a single port on an ‘Accessory Decoder and only needs one single point operating button to be pressed to operate both points in synchronisation.

RailMaster Pro has a feature where operating one accessory can be linked ‘virtually’ in the RailMaster software to operate further defined accessories.

This screen grab below with example addresses shows how the point configurations are constructed in RailMaster Pro to achieve this design & configuration goal.

For the purpose of this tutorial the following assumptions and considerations have been made:

1. The total number of ‘Accessory Decoders’ used on this layout does not exceed 4 x 4 port OR 2 x 8 port making 16 Accessory Decoder ports in total.
2.  It is also assumed that the ports have been given DCC Addresses 1 to 16.
3. The DCC Address 20 allocated for Point B is a ‘virtual dummy’ address for which NO physical Accessory Decoder port exists.
4. Both point motors [Point A&B] have been wired in parallel from the 8^th Accessory Decoder port [in this example, port 4 on a second R8247 four port decoder] and been given the DCC Address 8 to match.
5. When DCC Address 8 is operated, the point motors are wired such that the two alternative routes are correctly set physically, even if the blue point position indicators are [at this stage of the configuration process] out of synchronisation. Note that point position indicators do not display in the design screen. I have only added them to the images in this tutorial to aid description, nor do they appear on the main track plan screen until after they have been configured in the track design screen first.
6. The ‘Start-up’ position is configured to set the straighter lower track path route.

Configuring the ‘Point Settings’ control dialogue boxes.

In the Point A configuration dialogue box on the left in image above, configure the following:

Controller = A if using a single controller for the whole layout or B if using a dual controller RailMaster configuration where controller B is dedicated for operating accessories.

Decoder port = the DCC Address of the actual Accessory Decoder port physically wired to the two passing loop points. In this example the DCC Address is 8.

Type = in this example Hornby R8247 4-port decoder, but use the pull down box for your particular decoder if listed. It should be noted however, that if operational difficulties are observed or your particular decoder is not listed then most Accessory Decoders will still function if the R8247 decoder is selected here.

Start-up position = this data value defines the order in which each point is initialised during the RailMaster start-up process. It is desirable to allow this start-up initialisation sequence to happen, but can be disabled for individual points by entering a zero value [as shown] for this specific point. I recommend that a non-zero value is entered, which needs to be a unique number and increment sequentially. For example, if you have 16 working points then this field in the point configuration boxes for each point would number sequentially from 1 to 16. This point initialisation process requires the ‘Set Points’ check box to be enabled on the RailMaster ‘System Settings’ screen as highlighted below:

The pull down left & right selection defines which way the point will switch as part of the initialisation RailMaster start-up process. In this example, choosing ‘Right’ sets the lower straight track path route through the ‘passing loop’.

At this stage of the proceedings, do not try to create the data entries in the ‘OTHER POINT / SIGNAL’ box. All the point & accessory addresses being used on the layout must be configured first, before these fields can be populated. This is because only previously configured points & accessories will appear in the configuration selection box when displayed.

Conversely, in the Point B configuration dialogue box, configure the following:

This Point B dialogue box is configured the same as Point A, but with these complementary variations:

Decoder port = the DCC Address of the ‘virtual dummy’ point address. In this example the dummy DCC Address is 20.

Start-up position = as there is no actual physical Accessory Decoder port associated with this point, leave the start-up order number as zero [disabled], but I would still set the start-up position as ‘Left’ to compliment the Point A configuration that was set to start-up switched to the ‘Right’. Not that this configuration setting will be acted upon. The initialisation of Point A will still set the point indicators correctly on the Point B screen icon.

Now that both the A&B points have had their basic configuration completed, you can now safely configure the ‘OTHER POINT / SIGNAL’ configurations in the Point A&B configuration dialogue boxes.

Clicking the field in the right hand side ‘OTHER POINT / SIGNAL’ panel displays a selection box for all the previously configured points and any other previously configured accessories.

In this Point B configuration box, select the point address 8 entries from the displayed selection list [or whatever address you have configured for Point A].

Two entries need to be added as shown in the previous two graphics, one for the Green button and one for the Red button. See why in the ‘How does this configuration work?’ section below.

Now go back to the Point A configuration dialogue box and edit it to add the point address 20 entries [or whatever address you have configured for Point B] into that points ‘OTHER POINT / SIGNAL’ configurations.

How does this configuration work?

Basically what is happening is that when you click the operating buttons on the ‘Point A’ point on your track plan, Point A will switch to the chosen direction. This will also at the same time invoke the ‘OTHER POINT / SIGNAL’ configuration to also switch the other linked point – Point B. Given that Point A is the one associated with the working configured Accessory Decoder port and is wired to both point motors, then the points will also switch accordingly to the chosen route.

Looking at the ‘OTHER POINT / SIGNAL’ configuration in a little more detail; Point B ‘Dummy Address 20’ point configuration details are being used in the image below:

The overall result of the above configuration being that clicking:

Point B [20] Green [Right] button triggers Point A [8] Red [Left] button.

Point B [20] Red [Left] button triggers Point A [8] Green [Right] button.

And conversely on the Point A point configuration dialogue

Point A [8] Green [Right] button triggers Point B [20] Red [Left] button.

Point A [8] Red [Left] button triggers Point B [20] Green [Right] button.

It should be noted that the exact same RailMaster configuration will work if Point B is instead wired to its own dedicated Accessory Decoder port. In other words the example DCC Address 20 is not a ‘dummy address’ but an actual working port address. If an actual Accessory Decoder port is used instead of a ‘dummy’ DCC Address, then the start-up zero number would need to be amended to a valid number within the available configured Accessory Decoder port address range.

The result of this ProPack only configuration is that you can click the track plan operating buttons on either of the two points [Point A or Point B] and both points will operate to create either the upper track route or the lower track route whilst at the same time, the blue point position indicator bars will display correctly in synchronisation on both points.

Using RailMaster Pro is the only way to achieve a one button press synchronised point position indicator solution, that doesn’t require each point to be manually operated separately as two distinct button pressing tasks.