This variant of the Time-Delay Relay operates much like the regular TDR, except that after being triggered by the rising edge of an input signal, it starts a timer. If the trigger signal goes away before the timer is done, the output is turned off then. However, if the timer completes while the trigger signal is still present, the output is turned off, and the TDR-T then waits for the trigger to go away before resetting. It can then only be turned on again by the input signal turning on and back off again.
Why would you want this? If you need something to only stay on a maximum amount of time before being turned off, this relay will allow you to accomplish that. The most common application is to allow a light to be turned on, but if someone forgets to turn it off, the TDR-T will turn it off to prevent the battery from being drained.
This relay has a selectable long-delay range setting, with a 0 to 30-minute maximum delay range. This can be useful if you need something to stay on longer than the standard 2-minute range.
Wiring these relays is the same as for the standard TDR and TDR-P relays, and there are positive-switching (TDR-PT) and negative-switching (TDR-T) versions.
|TDR-T Time-Delay Relay Timing Diagram|