DUAL TIMER
The Dual Timer consists of two separate timer circuits. Each circuit switches a single pole relay whilst it is timing. The length of timing is adjustable with a screwdriver, from a few seconds to 5 minutes. An LED is fitted to each timer to indicate when timing is underway.
Connecting 0 volts to the "IN" terminal starts the timing.
A switch, relay contact, IRDOT-P "P" terminal, IRDOT-1 terminal"2", or the "OUT" terminal of another Dual Timer circuit can all trigger the timer.
A combination of switches and output terminals can be wired to the same "IN" terminal.
The length of timing is the same whether "IN" has a short pulse or is held at 0 volts for a long time.
CONNECTIONS BETWEEN UNITS
All the units are designed to operate when their (input) terminals are connected to 0 volts. 0 volts is the negative connection of the power supply when DC is used.
To avoid confusion if an AC supply is used, we have called the voltage at terminals 6 of the IRDOTs and IRDASCs, terminal "0" or terminal "-" of the other units 0 volts.
Touching a wire between the 0 volts terminal and one of the input terminals will trigger a unit. This is useful for testing units during installation.
A switch or reed switch can also be used to make this connection.
Output Terminals (Terminal 2 of the IRDOT-1, Terminal "P" of the IRDOT-P, and the "TD" and "TIS" terminals of the IRDASC) all switch to 0 volts when activated. This allows these terminals to be wired to the input terminals.
For example terminal 2 of the IRDOT-1 can be wired to the "IN" terminal of the "Dual Timer". When the IRDOT 1 detects a train it will then start the Dual Timer timing. This arrangement gives a great amount of flexibility in combining units.
A combination of switches and output terminals can be wired to the same input terminal.
NOTES
The built in relay contacts are rated at 2 amps.
The use of change-over (double throw) contacts means that the switch can be wired as normally open or normally closed.
A push button switch could be wired to the "IN" terminal and the normally open relay contact to an electric motor. Pressing the push button switch would cause the motor to run for the adjustable time then stop.
By wiring the contacts as normally closed the opposite occurs; the motor or bulb will work until the push button switch is pressed, then switch off for the timing period.
This arrangement is used for the automated storage sidings where the normally closed contact isolates the storage sidings when triggered by the IRDOT-P. This gives the time delay between a train entering and the next one leaving the storage sidings.
Terminals "B" and "COM" (C) are connected while timing. Terminals "A" and "COM" are connected when not timing.
CHAINING DUAL TIMER BOARDS
The "OUT" terminal of one timer can be wired to the "IN" terminal of the next. When the first timer finishes timing it will start the second timer timing.
It is possible to wire a series of boards together in this way, forming a sequencer to switch on and off one electrical device after another.
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SPECIFICATION |
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| Voltage | 12 to 16 volts, AC or DC | |
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SIZE |
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| Inches | Millimetres | |
| Length x Width | 3.2 x 2.8 | 82 x 72 |