Fanuc keep relay parameters, denoted by the K address, are non-volatile memory bits used within the Programmable Machine Controller (PMC) to manage machine-specific logic and system configurations. Unlike standard internal relays (R) that reset when power is lost, keep relays retain their state (0 or 1) even after a machine shutdown, making them essential for persistent settings like tool change flags, interlocks, and optional hardware toggles. Core Functions of Keep Relay Parameters

Application Exclusivity: Tailoring a Standard Control to a Unique Machine

Perhaps the most powerful exclusivity of Keep Relays is their role as the customization layer for a mass-produced CNC. Every Fanuc control is a generic computing platform. It is the Keep Relay settings, defined by the machine tool builder (e.g., Haas, Mazak, DMG MORI), that turn this generic controller into a specific lathe, milling center, or press brake.

Potential Drawbacks

Introduction

Reserved for PMC software data; usually strictly for internal system use. Special Functions