HEIDENHAIN TNC 306 Technical Manual - Manual (Page 213)

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TNC 406/TNC 306 9 Short circuit/probing 4-113
The error message "Touch point inaccessible" appears if the maximum measuring range (MP6130) is
exceeded.
The probing sequence must be enabled by the PLC with marker M2503. This marker is set by the
NC after a probing cycle starts and the NC waits until the PLC resets marker M2503 before
executing the probing function. A number of conditions are transferred to the PLC with markers
M2022 to M2072. This information can be processed further in the PLC program. The probing
function is controlled entirely from the NC.
In all modes when the stylus is deflected and marker M2502 is set, the controller stops the
machine. If M2502 is not set, the controller only detects stylus deflection if the probing function has
started. This is why HEIDENHAIN recommend setting marker M2502 as soon as the touch probe is
in the spindle.
MP6120 Probing feed rate
Input range: 80 to 30000 [mm/min]
MP6130 Maximum measuring range
Input range: 0.001 to 99999.9999 [mm]
MP6150 Retraction feed rate in probing cycle
Input range: 80 to 30000 [mm/min]
Set Reset
M2502 NC STOP with deflected stylus in all modes PLC PLC
M2503 Enable marker for probing functions PLC PLC
M2022 Touch probe not ready (no standby signal at
connector X12) NC NC
M2023 Probe triggered before start of probing cycle NC NC
M2025 Probe triggered (probing sequence is executed) NC PLC
M2026 Probing sequence ended or interrupted NC NC
M2027 Low battery voltage (battery warning at connector
X12); only evaluated during the probing sequence) NC NC
M2028 Probing function activated (for switch on/off test
voltage) NC NC