The Dromesday Book

The Trap Control Flags allow you to control the flow of TurnOn and TurnOff messages through the trap on which they are set. Note that they have no effect if the script on that trap does not support use of the flags.

• Once - Only one message will ever be forwarded along the ControlDevice links leading from the object
• NoOff - Incoming TurnOff messages will be ignored and not forwarded
• NoOn - Incoming TurnOn messages will be ignored and not forwarded
• Invert - The message will be inverted before being forwarded on down links; i.e. on an incoming TurnOn, a TurnOff will be sent down links instead, and vice-versa

Note that multiple flags can be set. Naturally, setting both NoOff and NoOn effectively disables the trap, preventing it from forwarding either message. Combining Invert with NoOn means that an incoming TurnOn will not be forwarded as a TurnOff; however, an incoming TurnOff will still be inverted and sent as TurnOn. Also, a RelayTrap with Once, NoOff set is an effective means of insuring only one TurnOn is ever passed through the relay.