Why actuator type matters
Failsafe and latching describe what the mechanism does after the actuation command is removed. The choice affects system behavior during power loss, control-current duration, thermal loading, wiring and startup logic.
Failsafe operation
A failsafe switch returns to a predetermined mechanical RF position when actuator power is removed. Energizing the appropriate actuator moves the RF path away from that default state; removing power allows the return mechanism to restore the predetermined position. This is useful when loss of system power must produce a known RF state.
Latching operation
A latching switch remains in its last selected position after the actuation pulse is removed. A command to another position is required to move it again. Because continuous coil power is not inherently required to hold the RF state, latching can reduce steady-state power consumption and coil heating.
Power-loss behavior
The key architectural difference appears during loss of control power. A failsafe unit returns to its designated default position. A latching unit normally remains mechanically in the last commanded position. The system designer should decide whether a known default or state retention is safer for the application.
Command duration
A latching actuator must receive a command long enough for the mechanism to complete its movement. CEI’s switch-selection guidance notes that the actuation pulse should be at least as long as the switching time and describes a 30 ms minimum pulse as sufficient for the referenced pulse-latching guidance. The applicable product drawing remains controlling for a specific part.
Choosing between them
Choose failsafe when a defined unpowered RF path is required. Choose latching when retaining the selected path without continuous actuator current is advantageous. Also consider whether the controller can generate the required pulse commands and whether position indicators are needed for independent confirmation.
Key takeaway
Failsafe returns to a defined unpowered state; latching retains the selected state after the command is removed.