Code 702818: BT axis clamping defective! (don’t switch off machine)
Issue Description & Safety Warning
The Chiron Siemens-Control CNC has triggered a critical BT axis clamping defective! (don’t switch off machine) alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
Actuation "Clamp BT-axis clamping" was output, but the sensor return signal is missing. PLC input signal "BT-axis clamping clamped" must have the signal state (1) within 2 seconds. The error has the following effect: Feed Stop For safety reasons, it is no longer possible to unlock the protective doors. Actuation "Clamp BT-axis clamping" is cancelled so that the system doesn't have to constantly work against the clamping. Actuation "Unclamp BT-axis clamping" is output and the axis stays under control. Error messages Axes (>Z) BT axis clamping defective! (don’t switch off machine) 1. Press [FEED START] key. Actuation "Clamp BT-axis clamping" is output again. If the sensor signals the signal state (1), the machine continues to run. Otherwise, the clamping is unclamped again and the message is output again. 2. Switch to "Manual mode". NOTICE! Attention! The machine control must not be switched off. There is the danger that the clamping is no longer holding reliably and the axis could fall over. There is a danger to the machine! For safety reasons, the protective equipment can no longer be opened. 3. Move the BT axis to a position where it can't tip over. 4. Turn off the machine control with the key [Control OFF]. The protective door is unlocked after a delay time of 10 seconds. 5. Check the PLC input signal "BT-axis clamping clamped" and the "Clamp BT-axis clamping" actuation.
Source: CHIRON Error Message Overview, all series (Siemens control, V2.0.6, 2012)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Chiron Siemens-Control CNC Alarms
Chiron controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 702818 on the Siemens-Control CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Chiron's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 545 Chiron Siemens-Control CNC codes.
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