The Heidenhain TNC 335 control is a legacy workhorse in the machining industry, highly regarded for its robust shop-floor programming capabilities. Establishing reliable RS232 serial communication is critical for smooth PC-to-CNC data transfer. When performing drip-feeding (DNC operation), we strongly recommend utilizing the Heidenhain "Blockwise" protocol; this ensures uninterrupted execution, even when streaming complex, memory-intensive part programs. Common connectivity hurdles—such as baud rate mismatches or handshaking failures between software XON/XOFF and hardware RTS/CTS flow control—can often be resolved by verifying parity and stop bit synchronization. Ensure your cabling strictly adheres to the standard pinout to prevent data corruption or frame errors during transmission.
| Parameter | Value | Comments |
|---|---|---|
| Baud rate | - | Supports 110-38400. Recommendation: 4800 for program transfer. Blockwise protocol is highly recommended for DNC. |
| Device | EXT | RS232 interface |
| 5010.0 | 515 | - |
| 5010.1 | 17736 | - |
| 5010.2 | 16712 | - |
| 5010.3 | 279 | - |
| 5010.4 | 5382 | - |
| 5010.5 | 4 | - |
| 5020 | 104 | 7 Data bits, Even parity, 2 Stop bits, XOn/XOff (DC3) |
| 5030 | 1 | Blockwise protocol enabled (0 = Disabled) |
Cabling and Protocol
The Heidenhain TNC 335 utilizes an RS232 interface. A 9-pin to 25-pin serial cable is generally required for communication.
Ensure your DNC software is configured to support the Heidenhain Blockwise protocol to avoid communication errors when processing large part files.