HEIDENHAIN TNC 426 PB/M Technical Manual page 859

7 – 10
To start recording:
7 7 7 7 Press the soft key START TRACE.
To stop recording:
7 7 7 7 Press the STOP TRACE soft key, or the TNC terminates recording
automatically as soon as the trigger event occurs.
The "PCTR" indicator blinks in the status window as long as the TNC is
recording logical states. As soon as recording ends, you can use the arrow
keys to select the desired area in the TRACE buffer.
Example of a logic diagram:
HEIDENHAIN Technical Manual TNC 426, TNC 430