The CTC Locomotive Module 21mtc is being phased out. Its successor is the CTC-Lokmodul-M3.
The CTC Locomotive Module 21mtc is only suitable for locomotives with Märklin’s 21mtc interface. Due to the standardized plug, this locomotive module can be installed without soldering. For older locomotives, various adapter boards with larger solder pads or cables are available on the market.
| Property | Description |
|---|---|
| Optimized for | Locomotives with Märklin 21mtc interface |
| Dimensions | 30 x 15.5 mm |
| Processor | Espressif ESP32 |
| Input voltage | Approx. 9 V to 24 V DC, digital current, or AC (with support capacitor) |
| Motor output | 1x DC motor: continuous current 1.0 A, peak 2.8 A |
| Switching outputs | 6x 500 mA LowSide (F0L, F0R, AUX1 to AUX4) 2x Digital (AUX5, AUX6) |
| Max. total current | 2 A |
| Interfaces | CTC-IR receiver, train bus (e.g., as I2C), 2x servo, 2x input |
| Passive online current | TBD |
| Boot current | 50 mA at 15 V |
In the overview “CTC Locomotive Modules”, you will find additional modules and links to installation instructions.
Pin Assignment
Details on pin assignment and dimensions can be found in the RailCommunity Standard RCN-121.
The image shows the first version:
Connection
Notes:
- When selecting the input voltage, always ensure that motors, lamps, etc., connected to the CTC module can also handle this voltage!
- The Zugbus is not supported by the current firmware.
- When soldering cables for the buffer capacitor, ensure they do not obstruct the insertion of the 21mtc socket.
To connect:
- Plug the CTC module onto the 22-pin 21mtc connector.
- Plug the optional CTC IR receiver onto the 10-pin socket on the CTC module (red marking faces toward the center of the board).
The assignment of light and AUX connections to switches in the app can be freely configured (Cfg.xml).
Additional Connections
- Two additional switching outputs with a max. of 500 mA are available under ExtOut-1 and ExtOut-2.
- Two digital inputs are available under Input-1 and Input-2.
IR Receiver
For the IR receiver, we provide you with a cable featuring a matching 10-pin plug. When installed in a Märklin locomotive BR 247 (#36292), it looks like this:
