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  • CNC Alarms

    Fanuc Alarm 4509: ILLEGAL COMMAND IN CUT AT ANGLE

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 4509: ILLEGAL COMMAND IN CUT AT ANGLE Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description In a cut-at-angle (G89) command, the traveling pitch (Q) was set to zero, negative value, or another value larger than or equal to the length (I). Alternatively, I, J, P, or…

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  • CNC Alarms

    Fanuc Alarm 4508: ILLEGAL COMMAND IN RADIUS

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 4508: ILLEGAL COMMAND IN RADIUS Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description In a radius (G88) command, the traveling pitch (Q) or radius (I) was set to zero or a negative value, or the traveling pitch (Q) was greater than or equal to the arc…

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  • CNC Alarms

    Fanuc Alarm 4507: ILLEGAL COMMAND IN SQUARE

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 4507: ILLEGAL COMMAND IN SQUARE Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description In a square (G87) command, the tool size (P,Q) was set to zero or a negative value, or the blanking length (I, J) was three times larger than the tool size (P, Q)…

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  • CNC Alarms

    Fanuc Alarm 4506: ILLEGAL COMMAND IN SHARE PROOFS

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 4506: ILLEGAL COMMAND IN SHARE PROOFS Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description In a shear proof (G86) command, the tool size (P) was set to zero, or the blanking length (I) was 1.5 times larger than the tool size (P) or less. Alternatively, I,…

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  • CNC Alarms

    Fanuc Alarm 4505: ILLEGAL COMMAND IN GRID

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 4505: ILLEGAL COMMAND IN GRID Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description In a grid (G78, G79) command, the number of holes (P, K) was set to zero or a negative value. Alternatively, I, J, K, or P was not specified. Have you faced Fanuc…

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  • CNC Alarms

    Fanuc Alarm 4504: ILLEGAL COMMAND IN ARC

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 4504: ILLEGAL COMMAND IN ARC Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description In an arc (G77) command, the radius (I) or the number of holes (K) was set to zero or a negative value. Alternatively, I, J, K, or P was not specified. Have you…

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  • CNC Alarms

    Fanuc Alarm 4503: ILLEGAL COMMAND IN LINE AT ANGLE

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 4503: ILLEGAL COMMAND IN LINE AT ANGLE Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description In a line-at-angle (G76) command, the number of holes (K) was set to zero or a negative value. Alternatively, I, J, or K was not specified. Have you faced Fanuc Alarm…

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  • CNC Alarms

    Fanuc Alarm 4502: ILLEGAL COMMAND IN BOLT HOLE

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 4502: ILLEGAL COMMAND IN BOLT HOLE Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description In a bolt hole circle (G26) command, the radius (I) was set to zero or a negative value, or the number of holes (K) was set to zero. Alternatively, I, J, or…

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  • CNC Alarms

    Fanuc Alarm 4500: REPOSITIONING INHIBITED

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 4500: REPOSITIONING INHIBITED Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description A repositioning command was specified in the circular interpolation (G02, G03) mode. Have you faced Fanuc Alarm 4500 REPOSITIONING INHIBITED on your machine? Share your experience or troubleshooting tips in the comments below to help other…

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  • CNC Alarms

    Fanuc Alarm 253: G05 IS NOT AVAILABLE

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 253: G05 IS NOT AVAILABLE Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description M series;Alarm details Binary input operation using high–speed remote buffer (G05) or high– speed cycle machining (G05) has been specified in advance control mode (G08P1). Execute G08P0, to cancel advance control mode, before…

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  • CNC Alarms

    Fanuc Alarm 252: ATC SPINDLE ALARM

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 252: ATC SPINDLE ALARM Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description An excessive error arose during spindle positioning for ATC. For details, refer to diagnosis No. 531. (Only for ROBODRILL) Have you faced Fanuc Alarm 252 ATC SPINDLE ALARM on your machine? Share your experience or…

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  • CNC Alarms

    Fanuc Alarm 251: ATC ERROR

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 251: ATC ERROR Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description This alarm is issued in the following cases;– An M06T_ command contains an unusable T code.;– An M06 command has been specified when the Z machine coordi nate is positive.;– The parameter for the current…

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  • CNC Alarms

    Fanuc Alarm 245: T–CODE NOT ALOWEE IN THIS BLOCK

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 245: T–CODE NOT ALOWEE IN THIS BLOCK Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description T series;One of the G codes, G50, G10, and G04, which cannot be specified in the same block as a T code, was specified with a T code. Have you faced…

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  • CNC Alarms

    Fanuc Alarm 5407: ILLEGAL COMMAND IN G41.3

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 5407: ILLEGAL COMMAND IN G41.3 Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description 1) A G code that belongs to group 01 except G00 and G01 is specified in G41.3 mode.;2) An offset command (a G code belonging to group 07) is specified in G41.3 mode.;3)…

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  • CNC Alarms

    Fanuc Alarm 5406: G41.3/G40 FORMAT ERROR

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 5406: G41.3/G40 FORMAT ERROR Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description 1) A G41.3 or G40 block contains a move command.;2) A G1.3 block contains a G code or M code for which buffering is suppressed. Have you faced Fanuc Alarm 5406 G41.3/G40 FORMAT ERROR on…

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  • CNC Alarms

    Fanuc Alarm 5405: ILLEGAL PARAMETER IN G41.2/ G42.2

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 5405: ILLEGAL PARAMETER IN G41.2/ G42.2 Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description The parameter setting that determines the relationship between the rotation axis and rotation plane is incorrect. Have you faced Fanuc Alarm 5405 ILLEGAL PARAMETER IN G41.2/ G42.2 on your machine? Share your experience…

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  • CNC Alarms

    Fanuc Alarm 5403: SPL:CAN NOT MAKE VECTOR

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 5403: SPL:CAN NOT MAKE VECTOR Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description Three–dimensional tool compensation vectors cannot be generated.;· When a three–dimensional tool compensation vector is created for the second or subsequent point, that point, previous point, and next point are on the same straight…

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  • CNC Alarms

    Fanuc Alarm 5402: SPL:ILLEGAL AXIS MOVING

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 5402: SPL:ILLEGAL AXIS MOVING Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description A movement is made along an axis that is not the spline interpolation axis. For example, in three–dimensional tool compensation mode using an offset vector of which components are the X–, Y–, and Z–axes,…

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  • CNC Alarms

    Fanuc Alarm 5401: SPL:ILLEGAL COMMAND

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 5401: SPL:ILLEGAL COMMAND Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description In a G code mode in which specification of G06.1 is not permitted, G06.1 is specified. Have you faced Fanuc Alarm 5401 SPL:ILLEGAL COMMAND on your machine? Share your experience or troubleshooting tips in the comments…

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  • CNC Alarms

    Fanuc Alarm 5400: SPL:ILLEGAL AXIS COMMAND

    ByCNC Hub Team October 1, 2026

    Fanuc Alarm 5400: SPL:ILLEGAL AXIS COMMAND Fanuc Control Model: 16 / 18 / 21-Series, 16i/18i/21i and 30i/31i/32i series Fanuc Alarm Description An axis specified for spline interpolation or smooth interpolation is incorrect. If an axis that is not the spline axis is specified in spline interpolation mode, this alarm is issued. The spline axis is…

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