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 work. For older locomotives, there are various adapter boards with larger solder pads or cables 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 or digital current or AC (with buffer 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 AUX 4) 2x Digital (AUX5, AUX6) |
| Total current max. | 2 A |
| Interfaces | CTC-IR receiver, train bus (e.g., as I2C), 2x servo, 2x input |
| Online passive 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 Configuration
Details about pin configuration and dimensions can be found in the RailCommunity Standard RCN-121.
The image still shows the first version:
Connection
Notes:
- When choosing the input voltage, be sure to remember that motors, lamps, etc., connected to the CTC module must also tolerate this voltage!
- The train bus is not supported by the current firmware.
- When soldering cables for the buffer capacitor, ensure that the 21mtc plug is not obstructed.
To connect:
- plug the CTC module onto the 22-pin 21mtc connector.
- plug the optional CTC IR receiver into the 10-pin socket on the CTC module (red marking faces the center of the board).
The assignment of the light and AUX connections to switches in the app can be freely configured (Cfg.xml).
Additional Connections
- Two additional switching outputs with a maximum of 500 mA are available under ExtOut-1 and ExtOut-2.
- Two digital inputs are available under Input-1 and Input-2.
IR Receiver
We provide you with a cable with a matching 10-pin plug for the IR receiver. Installed in a Märklin locomotive BR 247 (#36292), it looks like this:
