Code 14040: [Channel %1: ] Block %2 error in end point of circle
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical [Channel %1: ] Block %2 error in end point of circle 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 Definitions: In circular interpolation, either t he circle radii for the initial point and the end point are further apart, or the circle center points are further ap art, than specified in the machine data. 1. In circle radius programming the starting and end points are identical, thus the circle position is not determined by starting and end points. 2. Radii: The NCK calculates from the present st art point and the other programmed circle parameters the radii for the start and the end point. An alarm message is issued if the differ ence between the circle radii is either - greater than the value in the MD21000 $MC_CIRCLE_ERROR_CONST (for small radii, if the programmed radius is smaller than the quotient of the machine data MD21000 $MC_CIRCLE_ERROR_CONST divided by MD21010 $MC_CIRCLE_ERROR_FACTOR), or - greater than the programmed radius multiplied by the MD21000 $MC_CIRCLE_ERROR_FACTOR (for large radii, if the programmed radius is greater than the quotient of the machine data MD21000 $MC_CIRCLE_ERROR_CONST divided by MD21000 $MC_CIRCLE_ERROR_FACTOR). 3. Center points: A new circle center is calculated us ing the circle radius at t he starting position. It lies on the mid-perpendicular positioned on t he connecting straight line from the starting point to the end point of the circle. The angle in the radian measur e between both straight lines from the starting point to the center calculated/programmed as such must be lower than the root of 0.001 (corresponding to approx. 1.8 degrees). Reaction: Correction block is reorganized. Interface signals are set. Alarm display. Remedy: Please inform the authorized personnel/service department. Check MD21000 $MC_CIRCLE_ERROR_CONST and MD21000 $MC_CIRCLE_ERROR_FACTOR. If the values are within reasonable limits, the circle end point or the circle mid-point of the part program block must be programmed with greater accuracy. Program Continuation: Clear alarm with NC ST ART or RESET key and continue the 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 14040 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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