This variant of the Time-Delay Relay operates a little differently than the normal one. When it is triggered by one of the inputs, it waits for the programmed turn-on delay, then turns on. Then, it immediately starts the countdown for the programmed turn-off delay, and turns off, even if the input signal is still present. It can then only be turned on again by the input signal turning off and back on again.
Why would you want this? If you require a fixed time-delay, regardless of the length of the trigger signal, this relay will do that. One customer asked for this feature so that he could connect it to a bright, flashing red light, and trigger it with his brakes. He set the turn-on delay to zero, and the turn-off delay to 3 seconds. This way, every time he hit his brakes, this flashing light turned on for 3 seconds, and then turned off. (Note, the TDR-M does not have any flashing logic; in this application, the customer's light did the flashing whenever it was powered on.)
The specifications for this relay are the same as the normal TDR, just that it immediately starts the turn-off countdown as soon as it turns on.
This relay now has a selectable long-delay range setting, with a 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-PM) and negative-switching (TDR-M) versions.
|TDR-M Time-Delay Relay Timing Diagram|