Latching Output
A relay output style that latches on one press and stays on until a second press. It is useful in applications such as lighting, ventilation or a continuously running pump. It is not suitable for lifting applications or those with a moving load, because the movement continues even if the operator releases the remote control.
On a latching output, the receiver interprets the incoming command as a change of state: if it is off it turns on, if it is on it turns off. When the command frame stops, the output holds its position. This behaviour is the exact opposite of a momentary output.
Suitable and unsuitable areas of use separate clearly:
- Suitable: site lighting, fans, circulation pumps, heaters — loads that do not move and whose stopping is not urgent.
- Not suitable: hoisting, traversing, boom, slew, gate movement — that is, anything whose stopping must depend on the operator's immediate intent.
The second safety problem with a latching output is what happens when the supply is lost and comes back. The output turning on by itself when power returns means automatic restart and can cause unexpected movement on the machine. Test this scenario deliberately during commissioning.
The output behaviour of AXI's ST and SF series remote controls is defined in the product data as an on/off relay contact; confirm from the user manual whether the output works as latching or momentary.
The context in which this term is used: Wireless Crane Remote Control Selection Guide