Basic Concept

CTC is a system of hardware and software for controlling model railways. It includes the following features:

• CTC Modules: Electronic units for controlling locomotives, turnouts, signals, lighting, action blocks, etc. Each CTC module handles local control tasks such as motor control, turnout switching, lights on/off, etc., with local firmware and configuration. The respective configuration is stored decentrally in the associated CTC module.
• CTC App: The software serves as the user interface (Graphical User Interface) and can be used on a smartphone, tablet with Android or iOS, or on a PC with Windows, MAC, or Linux. A dedicated and costly central control unit is not required.
• CTC modules are configured via the CTC app.
• Communication via WLAN: Communication between the CTC app and CTC modules, as well as between the CTC modules themselves, occurs through a dedicated WLAN access point (e.g., a FritzBox). The transmission speed is up to 54 Mbit/s. Apart from the power supply, no wiring is necessary.
• The CTC app addresses the CTC modules. The graphical user interface allows the user to control driving speed, turnout settings, signal lights, etc.
• Exact position determination: Using dedicated infrared transmitters on the track and infrared receivers in the locomotive, the CTC app can determine the exact position.
• Parallel operation with other “market-standard” digital and analog systems is possible.

The CTC App

The CTC app allows control of locomotives, turnouts, lighting, action blocks, etc., from a PC with Linux, Mac, or Windows, as well as from smartphones and tablets with Android and soon also iOS. Shown above is the PC version.

The app does not store any data about the model railway. Upon start, it reads all necessary information from the respective CTC modules and constructs its interface with it. Even the pictures of the locomotives and the track layout displayed at the bottom of the app are read from the corresponding CTC modules.

The configuration of the CTC modules, uploading of firmware, and the (one-time) registration of CTC modules into the model railway WLAN are conveniently done via the CTC app. A special feature is the automatic calibration of the motor sensor of locomotive modules and the graphically supported tuning of the motor parameters (PID controller).

The app coordinates communication with the modules to ensure smooth communication even in large model railways with many CTC modules.

Installation

Software:

• The app for Android is currently provided as an apk file. In the future, apps for Android and iOS will be installed via their respective app stores.
• The PC application is provided as a zip file and can be started directly after unpacking.
• The Access Point (Router) is delivered fully installed by us. Consequently, we have all the details such as the SSID and password of the WLAN. These details will be provided to you in a protocol.
• Of course, you can also configure a WLAN router yourself.
• In both variants, we can deliver the device modules fully configured. The app contains menu items to enroll and configure device modules into the WLAN.

Hardware:

• The installation of the CTC locomotive module in a locomotive is comparable to installing a decoder for conventional digital control systems: Basically, four wires need to be connected: 2x to the rails and 2x to the DC motor with permanent magnets in the stator. Wound stators are also possible. Additional functions such as lights and couplers would also need to be wired.
• The installation of the CTC modules in turnouts is also comparable to installing a decoder for conventional digital control systems. For Märklin C-track, there is the CTC turnout module for installation in the turnout with the same form factor as the Märklin decoders. For all other track systems, either the CTC turnout module or a CTC multi I/O board can be used. We offer various common plug and screw systems for connecting the cables.
• Two IR balises for position determination can be connected to a CTC turnout module or a CTC multi I/O board

Enrolling device module into WLAN:

• Configuration mode: A new device module (without WLAN configuration) sets up its own WLAN and waits to be configured.
• If an already configured device module does not find its WLAN, it switches to configuration mode after one minute, waits for a connection for one minute, and then resets automatically.
• The CTC app can detect modules in configuration mode at the push of a button and write the WLAN configuration to the device module. After writing the WLAN configuration, the device module resets automatically and enrolls into the model railway WLAN.

Enrolling control device into WLAN:

• The device (PC, tablet, smartphone) with the CTC app is enrolled into the LAN or WLAN as usual for that device.

Commissioning (Boot Process)

As soon as the WLAN is available after starting the access point, the control devices can be connected to the LAN/WLAN as usual for that device.

The fully installed device modules automatically connect to the WLAN as soon as they receive power.

The CTC app automatically detects all device modules available in the same WLAN. Device modules that start later become visible in the app as soon as they are enrolled in the WLAN. Enrolling a device module takes one to a few seconds, provided the reception quality is good. If a dead spot exists, the usual options for improving wireless coverage, such as repeaters, can be used.

For the actuators connected to device modules (e.g., turnout, signal), a basic position can be entered in the device configuration. This position is assumed directly after the module starts, e.g., turnout straight or signal stop. Alternatively, the initial position can be read through a sensor input. Changes in configuration are menu-driven in the CTC app.

Track Layout

Using the CTC app, a simple track layout can be created in the form of a grid, as is now known from many model railway control centers or control programs. As usual for CTC, this is stored in the model railway modules as follows:

• For each contiguous segment of the model railway (e.g., a board or a standard module), one selects a turnout or IO module permanently installed on this segment. The track plan of the segment is stored in this module.
• For each individual turnout, signal, switching function, light, etc., the coordinate within the segment track plan is stored in the respective module.
• For the entire model railway, another module is selected to store the arrangement of individual segments into an overall track plan. The layout can also be divided into multiple track plan sections or levels.

The track plan is conveniently edited via the CTC app.

When the app starts, it finds the overall track plan and displays it. Turnouts, signals, etc., can now be controlled via the track layout display. The current switch position is, of course, displayed.

Position Determination

Using infrared signals, a CTC locomotive can determine its position with an accuracy of a few centimeters. Two infrared transmitters can be connected to each turnout and IO module. These are then installed in the track bed. Moreover, an infrared receiver must be connected to the locomotive module and mounted on the underside of the locomotive.

Via the app, each infrared transmitter is assigned an ID and the distance in centimeters to the IR balise behind it is recorded. This consists of the ID of the associated track section (2 characters) and a running number. The IR balises of a track section are numbered sequentially in a clockwise direction. Additionally, the position of the IR balise is noted in the track plan.

The IR balise now cyclically sends its ID, the distance to the previous IR balise, and optionally a command. When the locomotive passes over the IR balise, it can determine its travel direction and average speed since the last read IR balise using the read ID and distance. The locomotive transmits the read ID and calculated speed to the CTC app, which can then display the locomotive’s position including travel direction.

Track sections with a constant incline (or decline) between two IR balises that are completely straight or consistently curved can also be used to calibrate the motor sensor of the locomotive module. The CTC app can automatically perform this calibration in a suitable loop course.

With a well-calibrated motor sensor, the locomotive can now estimate its speed (in mm/s) and its distance to the last IR balise. If the model railway layout has an IR balise approximately every 60 to 100 cm, position determination becomes accurate to a few centimeters.