Fanuc | Keep Relay Parameters Exclusive

However, the power of Keep Relays comes with a significant engineering responsibility: the risk of "latched" logic errors. Because these relays retain their state, they do not naturally reset to a "safe" default state upon power-up like standard relays do. If a Keep Relay is used to latch an error state or an unsafe condition, simply cycling power will not clear the fault; the machine will wake up in an error state. Therefore, the logic surrounding Keep Relays must be exclusive and rigorous. It usually requires an explicit "unlatch" or reset condition in the ladder logic. If a technician mistakenly uses a Keep Relay for a transient signal (like a pulse to trigger a single cycle), the machine may get stuck in that cycle indefinitely. This highlights the necessity for programmers to treat Keep Relays not as general-purpose variables, but as permanent registers reserved for specific, persistent data.

Ensure specific relay (keep-relay) parameters persistently remain enabled/unchanged and are not overwritten by automatic parameter loads, backups, or other user changes on FANUC CNC controls. fanuc keep relay parameters exclusive

Reserved for core system functions, such as the safety circuit interface (e.g., K928.7 or K929.0). How to Access and Modify However, the power of Keep Relays comes with

Changing these parameters requires cautious access to the PMC maintenance screens. Set the machine to MDI mode . Therefore, the logic surrounding Keep Relays must be