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Adding/Editing Signal Heads

Simple Signal Logic panel figure

JMRI needs to know how a signal head on the layout is connected to the electrical hardware. Once it knows that, it can send the right commands to control the appearance of the signal head.

The "Add Signal Head" dialog gives you a number of different choices for how the signal head is connected:

Triple Output
This type controls a signal head via three electrical connections. One goes to a green lamp/LED, one to a yellow one, and the third to a red one.

These connections are controlled via the JMRI Turnout logic, and therefore appear in the Turnout Table. They're not really connected to switch motors, though, they're just electrical outputs.

For each connection, enter the appropriate JMRI turnout for the electrical connection on the layout, either as a number (1,2,3) or as a JMRI name (system name like LT1, CT2 or an already-defined user name). They need not be consecutive or in any particular order.

If you need to debug one of these signal heads, start by checking whether the Turnout connections work. You can do this by going to the Turnout Table and changing the output setting there. Setting e.g. the turnout on the "green" connection Thrown should light the green lamp.

Double Output
This type controls a signal head via two electrical connections. One goes to a green lamp/LED, and the other to a red one. Yellow is created by turning them both on at the same time.

These connections are controlled via the JMRI Turnout logic, and therefore appear in the Turnout Table. They're not really connected to switch motors, though, they're just electrical outputs.

For each connection, enter the appropriate JMRI turnout for the electrical connection on the layout, either as a number (1,2) or as a JMRI name (system name like LT1, CT2 or an already-defined user name). They need not be consecutive or in any particular order.

If you need to debug one of these signal heads, start by checking whether the Turnout connections work. You can do this by going to the Turnout Table and changing the output setting there. Setting e.g. the turnout on the "green" connection Thrown should light the green lamp.

Quadruple Output
This type controls a signal head via four electrical connections. One goes to a green lamp/LED, one to a yellow one, one to a red one, and the fourth to a "lunar" (white) one.

These connections are controlled via the JMRI Turnout logic, and therefore appear in the Turnout Table. They're not really connected to switch motors, though, they're just electrical outputs.

For each connection, enter the appropriate JMRI turnout for the electrical connection on the layout, either as a number (1,2,3) or as a JMRI name (system name like LT1, CT2 or an already-defined user name). They need not be consecutive or in any particular order.

If you need to debug one of these signal heads, start by checking whether the Turnout connections work. You can do this by going to the Turnout Table and changing the output setting there. Setting e.g. the turnout on the "green" connection Thrown should light the green lamp.

Single Output
This type controls a signal head with a single electrical connections. The connection can be to a single lamp/LED to display a single apperance. An alternative method is to connect a pair of LEDs to the single output wired up suitable so that when the output of the decoder is on you get one color and while the output is off you get the other. This type could also be used to control mechanically operated signals that only have two appearances and therefore always have an appearance. It is possible to gain a third "flashing" appearance. If you have Dark and a colour selected, then the end result is an additional flash color option If there are two colours selected, then you are given flash for both colours, however this will either flash option will result in the colours flashing alternatively.

These connections are controlled via the JMRI Turnout logic, and therefore appear in the Turnout Table. They're not really connected to switch motors, though, they're just electrical outputs.

For each connection, enter the appropriate JMRI turnout for the electrical connection on the layout, either as a number (1,2,3) or as a JMRI name (system name like LT1, CT2 or an already-defined user name). They need not be consecutive or in any particular order.

If you need to debug one of these signal heads, start by checking whether the Turnout connections work. You can do this by going to the Turnout Table and changing the output setting there.

Appearance Closed - The appearance given when the connection is in the Closed State.

Appearance Thrown - The appearance given when the connection is in the Thrown State.

Virtual
This type doesn't connect to the layout at all. Use it when you want to e.g. display a signal on a panel, but don't have a real one on the layout.
SE8c 4 Aspect
This type controls signal heads attached to a Digitrax SE8c signal driver card.

Because each SE8c 4 Aspect signal head works with a specific DCC address, its system name is determined automatically from that address. You don't have to enter it. For example, the SE8c 4 Aspect signal head for hardware address 257 will be given a system name based on that.

You can optionally enter a user name if you'd like.

In the "Turnout number" field, enter the appropriate DCC address of the SE8c output as a number. For example, the 1st signal head on the 1st SE8c, as configured from the Digitrax factory, is addressed by putting a "257" here. See e.g. page 5 and 7 of the Digitrax SE8c manual (http://www.digitrax.com/ftp/se8c.pdf). In this case, don't enter anything in the "Second Turnout" field.

Alternately, if you're using more than one hardware type, you might need to specify a full user or system name. In that case, put the name for the lower turnout address, e.g. NT257, in the "turnout number" field, and the upper turnout address, e.g. NT258, in the "Second Turnout" field.

LDT LS-DEC
This type is particularly useful for European signaling. It controls signal heads attached to a Littfinski DatenTechnik (LDT) LS-DEC signal decoder, or a Marathon Model DP2N decoder.

These controllers use seven DCC turnout (accessory decoder) addresses to specify the seven possible appearances of the signal. Enter those, either as numbers (1,2,3,...) or as JMRI turnout names (system names like LT1, CT2 and/or already-defined user names), in the appropriate text fields.

For more information on configuring these signals, see the examples page.

DCC Signal Decoder
This type controls signal heads attached to a decoder that uses the DCC signal packets defined by the NMRA DCC Working Group for control. This is a special protocol defined for driving signal heads, and is different from how "accessory decoders" (e.g. turnout outputs) are controlled.

Enter the DCC address as a number.

Grapevine
This type controls signal heads attached to a ProTrak Grapevine node.

In the text field, enter a system name for a Grapevine signal head, e.g. GH1204 for the 4th connector on the 2nd bank connector of the 1st node. For more information on how those names are generated, see the page on Grapevine names.

MERG Signal Driver 2
This type controls a signal that uses a MERG Signal Driver 2 to control its displayed aspects. The SD2 is driven using a steady State accessory decoder. Depending upon the number of aspects that are displayed on the signal, will determine the number of turnout outputs are required. ie.
2 Aspect requires 1 turnout
3 Aspect requires 2 turnouts
4 Aspect requires 3 turnouts

The Signal driver on JMRI has been setup to control the aspect output only for the SD2, it does not control the other features of the SD2 such as "Steam Rules" or "Feather". However these can easily be configured using normal Logixs or routes.

Notes - The MERG SD2 driver does not support flashing yellow aspect, for flashing yellow aspects an additional circuit is required as documented in the MERG Technical Bulletins.
As the MERG SD2 driver goes beyond the Green/Yellow/Red Aspects supported in JMRI with a double yellow aspect, the double yellow state is represented in the status as a "Lunar".

Further information on the Signal Driver can be found at MERG

The "Edit Signal Head" dialog (window) provides for viewing and changing optional information for existing signal heads. Use the "Edit" buttons in the Signal Head Table to select a signal head. Signal type and system name may not be changed. After making changes in the dialog, click "Update" to change signal head information. Click "Cancel" to exit without making any changes. Closing the Edit Signal Head window is equivalent to clicking "Cancel". Only one signal head may be edited at a time.