Code 21701: [Channel %1: ] Block %3 axis %2 measurement not possible
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical [Channel %1: ] Block %3 axis %2 measurement not possible 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 = Axis name, spindle number %3 = Block number Definitions: Measurement level 2 (MEASA, MEAWA, MEAC). There is an error in the programmed measurement task. Possible causes: - Invalid measurement mode - Invalid probe - Invalid encoder - Invalid number of measurement signal edges - Identical measurement signal edges are only programmable in mode 2 - Invalid FIFO number - Mismatch between the number of FIFOs programmed and the number of probes used in the measurement task. Further causes: A measurement task is already active (e.g. from a synchronized action). Reaction: Local alarm reaction. NC Start disable in this channel. Interface signals are set. Alarm display. NC Stop on alarm. Remedy: Correct the measurement tasks. Program Continuation: Clear alarm with the RESET key. Restart part program
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 21701 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.
Have a better solution?
Help the industrial community by sharing your repair experience for code 21701.
Need a searchable reference for more Siemens SINUMERIK 840D CNC manuals?
We structure equipment manuals into searchable code, title, cause, solution, safety note, and source-reference data. Send a PDF and example searched codes when you need public pages, private search, or structured exports.
Space reserved for Google AdSense / Industrial Affiliate Links
Monetization target for 2026