Code 21800: [Channel %1: ] Workpiece setpoint %2 reached
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical [Channel %1: ] Workpiece setpoint %2 reached 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 = Workpiece setpoint Definitions: This alarm is activated via MD27880 $MC_PART_ COUNTER, bit 1: The number of counted workpieces ($AC_ACTUAL_PARTS or $AC_SPECIAL_PARTS ) is equal or already greater than the programmed value for the number of required workpi eces ($AC_REQUIRED_PARTS). At the same time, the channel VDI signal "Workpiece setpoint reached" is output. The value for the number of counted workpieces ($AC_ACTUAL_PARTS) is reset, whil e the value of $AC_SPECIAL_PARTS is retained. Note: The setpoint/actual comparisons of the workpieces are only made after an NC start under the condition that $AC_REQUIRED_PARTS > 0. If $AC_REQUIRED_PARTS has a negative value, all workpiece counts ac tivated through MD27880 $MC_PART_COUNTER are frozen at the values they have reached, and the nominal/actual co mparison is discontinued. Reaction: NC not ready. Interface signals are set. Alarm display. Remedy: No program interrupt. Delete alarm display. Program Continuation: Clear alarm with the Delete key or NC START.
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 21800 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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