Code 15020: Channel %1 block %2 CHANDATA inst ruction cannot be executed. Channel %3 is not active
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical Channel %1 block %2 CHANDATA inst ruction cannot be executed. Channel %3 is not active 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
Parameters: %1 = Channel number %2 = Block number, label %3 = String (CHANDATA parameter) Definitions: With a CHANDATA instruction, the data input for a channel is selected that has not been activated. For structural reasons, the input of mu lti-channel data must take place twice. Reaction: Interpreter stop NC Start disable in this channel. Interface signals are set. Alarm display. Remedy: Please inform the authorized personnel/service department. - Activate the channel concerned by m eans of machine data or option data or - Delete the CHANDATA instruction and all follow ing assignments to channel data. This error message occurs regularly when first reading in an INITIA L Init block with which a multi-channel system is to be installed. In this case: 1. NCK Restart must be executed in order to acti vate the global machine data already input for the installation of the other channels. 2. Input of the INITIAL Init block must be repeated. Program Continuation: Switch control OFF - ON.
Source: SINUMERIK 840D sl / 840Di sl / SINAMICS S120 Diagnostics Manual (DAsl, 03/2009)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Siemens SINUMERIK 840D CNC Alarms
Siemens controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 15020 on the SINUMERIK 840D CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Siemens's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 4014 Siemens SINUMERIK 840D CNC codes.
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