More on the Dolph Double Trap Circuit (DDT)
Recently you were introduced to the DDT; a way to configure two hold-up alarm (HUA) devised so that they follow suggested CSAA STA 1 document guidelines. This circuit allows for HUA device redundancy and the reduction of false alarms. If either device is accidentally activated a trouble signal is sent to the central station. If both devices are activated an alarm signal is transmitted.
There was also the suggestion from CSAA that a local indicator be applied for when a single HUA bill trap device is activated. As promised in the original Tech Talk article If you go to this DDT Circuit link you can download a diagram that will show you how to configure a DDT circuit with local LED annunciators.
Some items to note in this configuration:
- A bill must be placed in trap to close circuit.
- Relays are shown in a non-energized position, but will be energized when bill is place in bill trap.
- R1 Limit Current resistor rating is dependent on LED source.
- Alarm circuit should be programmed as a NO circuit with a short on alarm. Use the EOL provided or specified by panel manufacturer.
- You can make this configuration with using 12 VDC DPDT relay modules.
- If using wireless bill traps then substitute the receiver relays for the Bill Trap contacts in the circuit diagram.
- LED Trouble annunciators would typically be placed in a visible, yet remote location, such as a manager’s office. Either lighted LED would indicate that the a single bill trap is open and should be restored. Both lighted LED’s would indicate an alarm condition.
CAUTION: Be careful placing remote indicators or audible devices in such a location as to be observed by non-management personnel. Steps should be taken not to aggravate a dangerous robbery situation with either visual or audible HUA annunciation.
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