In Fanuc CNC systems, Keep Relays (K-parameters) are specific memory addresses that store binary (0 or 1) settings to control machine behavior or enable/disable PLC functions. Unlike standard NC parameters, Keep Relays are often defined by the Machine Tool Builder (MTB)
Enable Parameter Write: Navigate to the Setting Screen and set PARAMETER WRITE to 1. Navigate to PMC Maintenance: Press the SYSTEM key. Select the PMC soft key. Choose PMCPRM (PMC Parameters) and then KEEP-RL. fanuc keep relay parameters exclusive
Keep relays act as the interface between the machine's hardware and the PLC ladder logic. They are primarily used by Machine Tool Builders (MTBs) to define how a specific machine should behave without requiring a rewrite of the entire ladder program. Common uses include: In Fanuc CNC systems, Keep Relays (K-parameters) are
User Keep Relays (K0–K19): These are commonly used by machine builders to define machine-specific options, such as enabling a chip conveyor, bypassing a door interlock for maintenance, or configuring the Automatic Tool Changer (ATC) pattern. Select the PMC soft key
Persistent State: They act as "latching" relays, preserving settings like tool change flags or safety interlocks during power interruptions.