Fanuc 9900 Parameter List Jun 2026

FANUC CNC systems utilize parameters to define machine behavior, from servo gain to I/O assignments. Parameters 9900–9999 are distinct: they are set at the machine tool builder (MTB) level. Unauthorized or incorrect changes to these values can disable the CNC, corrupt the PMC (Programmable Machine Controller), or render the machine inoperable.

9900 – Axis count 9901 – Extra axis enable 9902 – Spindle type 9904 – High-speed cut 9906 – Software ID (RO) 9913 – Macro enable 9930 – Password lock 9970 – Option mask 9999 – Security checksum

Unlocks G68/G69 codes to rotate the program coordinates without changing the physical setup.

Different factory options (e.g., 4th axis rotary tables, high-speed machining packages). Variations in ball screw pitches and motor resolutions.

: Before changing a single bit, perform a full backup of all parameters (NC, PMC, and Diagnostics) to a PCMCIA card or USB drive.

These control the configuration of input/output signals, such as those for tool changers, coolant systems, and spindle control.

If you are trying to resolve a specific machine error or want to find out which options are currently active on your controller, let me know the you are working with (e.g., 0i-MD, 31i-B) or the specific feature you want to unlock. I can guide you on the exact parameter structure or troubleshooting steps required for your setup. Share public link

Working with the FANUC 9900 parameters carries significant risk. To avoid costly downtime and equipment damage, adhere to the following strict guidelines:

| Parameter | Typical Function | Data Type | Example Value | Notes | | :--- | :--- | :--- | :--- | :--- | | | Number of controlled axes (basic) | Byte | 2, 3, 4 | Set by MTB; changing causes mismatch | | 9901 | Option: Additional axes enable | Bitmask | 0x0001 | Enables 4th/5th axis options | | 9902 | Spindle configuration mode | Byte | 0=analog, 1=serial | Serial = FANUC spindle drive | | 9903 | PMC (ladder) type selection | Byte | 0,1,2 | 0=PMC-L, 1=PMC-M, 2=PMC-N | | 9904 | High-speed machining option | Bit | 0/1 | Enables AI contour control | | 9905 | Number of PMC I/O links | Byte | 1-8 | Must match hardware rack config | | 9906 | Software series ID | Read-only | e.g., 0x20A | Do not modify | | 9907 | Axis assignment order | 4-byte hex | 0x01020304 | Maps logical to physical axes | | 9908 | Servo software version lock | Binary | Factory set | Prevents servo mismatch | | 9910 | Option: Rigid tapping enable | Bit | 0/1 | Requires spindle encoder | | 9913 | Macro executor (A/B) | Byte | 0=no, 1=A, 2=B | Enables custom G-code macros | | 9915 | DNC operation enable | Bit | 0/1 | Allows drip-feed via RS-232 | | 9920 | Maximum spindle speed limit | Integer (rpm) | 6000 | Overridden by S command | | 9925 | PMC scan cycle time (ms) | Byte | 4,8,16 | Affects ladder response | | 9930 | Password key for 9900 edit | 8-digit hex | Random | Used by MTB for security | | 9940 | Axis stroke limit type | Bit | 0=standard, 1=dual | Changes overtravel logic | | 9950–9959 | OEM-defined machine constants | Various | MTB-specific | E.g., tool changer positions | | 9960 | CNC model ID (low byte) | Read-only | e.g., 0x10 | For option compatibility | | 9970 | Software option enable mask | 32-bit | Factory calc | Enables turning/milling/grinding | | 9980 | Backup checksum seed | Hex | Factory | Used for memory integrity | | 9999 | Security parity | Byte | Validates 9900 block | If wrong → system alarm |

Change the value from 0 to 1 . The control will issue a flashing "P/S 100 PARAMETER WRITE ENABLE" alarm. This is normal. Press the [SYSTEM] function key. Press the [PARAM] softkey. Search for 9900: