The Heidenhain TNC 145 control remains a cornerstone of precision machining, prized for its enduring reliability. Establishing stable DNC data transfer between your CNC machine and a modern PC requires precise RS232 interface configuration. To prevent common transmission errors such as parity mismatches, framing errors, or buffer overflows, ensure that your baud rate, parity, and stop bits are strictly synchronized. Furthermore, proper handshaking implementation is critical; while hardware flow control (RTS/CTS) is the preferred standard for this architecture to ensure data integrity, verify that your cabling matches the machine's DTE/DCE requirements. If you encounter checksum or communication timeout errors, double-check your terminal software for correct STX/ETX character encapsulation, as the TNC 145 relies on these specific delimiters to identify the start and end of program blocks during serial data processing.
| Parameter | Value | Comments |
|---|---|---|
| Baud Rate | 2400 | - |
| Parity | Even | - |
| Data Bits | 7 | - |
| Stop Bits | 2 | - |
|
Select RTS/CTS flow control in your DNC software. The software must insert STX and ETX codes into the data stream. ASCII Start Code = STX (02), ASCII End Code = ETX (03). |
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The illustrated cable is compatible with both xOn/xOff (DC1/DC3) and RTS/CTS (hardware flow control). For basic applications or where hardware flow control is not available, a 3-wire cable configuration may be utilized. See the diagram here.
RS232 Cable: 9-pin PC to 25-pin CNC
