In the FANUC ecosystem, parameters are divided into distinct functional blocks. While the 1000 series handles basic axis settings and the 8000 series manages macro variables, the 9000+ series is historically reserved for internal system configurations, option activation, and deep core variables. The Role of System Parameters
Configures the feedback pulses per motor revolution from the pulse coder (encoder).
Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 01 lines; Line 1: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 end-lines; Common FANUC 9900 Parameter Implementations
Based on typical Fanuc configurations, the bits for parameter 9900 often control foundational G-code and hardware behaviors: Canned Cycles Bit 1: G10 Program Input of Offset Bit 2: Mechanical Handle Feed Bit 3: Manual One Pulse Generator Control Bit 5: Inch / Metric Conversion Bit 6: Special G-Code Security and Access fanuc 9900 parameter list
Unlike volatile operational parameters, option parameters are deeply integrated into the system's FROM/SRAM memory.
Inputting an invalid combination of option bits can cause a system lockup, requiring a full SRAM clear and restoration from backups.
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. In the FANUC ecosystem, parameters are divided into
The parameter requires an OEM unlock password or option disk. Contact the machine tool builder or FANUC service. 5. Maintenance Best Practices
Note: Exact functions vary by FANUC series (0i, 16i, 18i, 30i, etc.). Below are the most consistent mappings.
The 9900 series is not a single-purpose list. It is a range of 100–200 parameters (depending on the CNC generation), each responsible for a high-level system feature. Below is the most common mapping for controls. Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit
Modifying 9900 series parameters without authorization from FANUC or your Machine Tool Builder is highly discouraged and can lead to severe consequences.
Occurs if you change a 9900 option that enables more servo axes than your physical Fanuc Servo Serial Bus (FSSB) amplifier hardware can support. Revert the parameter or check FSSB optical fiber connections.