Part Number: BOM-0018-B
Reproduces two individual alarm signals, delaying them for a pre-set time, to prevent unwanted, spurious alarms. Originally designed for reliable fire detection using Infrared (IR) thermal imaging cameras, the Contact Delay PCB can also be used for a variety of other applications in which signals need to be delayed.
The Contact Delay PCB ignores each alarm signal until the pre-set delay time has elapsed. The appropriate alarm output is then activated and is only de-activated when the alarm condition ends.
The delay times are individually set for each alarm signal using two rotary, hexadecimal switches (S1/S2), with switch positions configured and marked on the PCB in the following increments:
- 0s, 5s, 10s, 15s, 20s, 30s, 40s, 50s, 60s, 1½mins, 2mins, 2½mins, 3mins, 4mins, 5mins, 6mins.
The delay increments and ±1% typical timing accuracy is provided by firmware running on a Microchip PIC16F1824 microcontroller and can easily be changed. Please advise any specific delay requirements.
Although ±1% typical timing accuracy is sufficient for most applications, ADEPT Circuits Ltd can also add a 32,768Hz crystal onto the PCB and change the firmware, to achieve far greater timing accuracy.
Furthermore, the Contact Delay PCB can provide PIC firmware engineers with a reliable, industry-ready platform to develop many other signal timing orientated solutions.
The Contact Delay PCB includes:
- Two low power, alarm signal inputs, connected via a 4-way terminal block named ‘CONTACTS IN’ (J1), as follows;
- A low TTL voltage at the normally open ‘NO’ terminal, or closed to the adjacent ‘COM’ (0V) terminal via a transistor/relay, for an alarm.
- A high TTL voltage at the normally open ‘NO’ terminal, or open collector/drain/relay contact to the adjacent ‘COM’ (0V) terminal, for no alarm.
- Two medium or high power, voltage-free, alarm outputs, connected via two larger 4-way terminal blocks named ‘ALARM1 OUT’ (J3) and
‘ALARM2 OUT’ (J4), as follows;
- The normally open ‘NO’ terminal is closed to the adjacent ‘GND’ (0V) terminal via a transistor, for an alarm < 100mA at 30V DC maximum.
- The normally open ‘NO’ terminal is closed to the adjacent ‘COM’ terminal via a relay, for an alarm 100mA to 8A at 30V DC or 250V
- A normally closed ‘NC’ relay terminal is also provided.
- Two jumper links named ‘ALARM1’ (LK1) and ‘ALARM2’ (LK2), to select medium power (transistor) or high power (relay contact) alarm outputs.
- Nominal 9-12V DC supply input, connected via a 2-way terminal block named ‘DC POWER’ (J2).
- Transient over-voltage (20V/20A maximum), reverse-voltage, and over-current protection.
- Dimensions: 80mm x 52mm.
Note that the above alarm polarity and DC supply voltage range can easily be changed.
The Contact Delay PCB is capable of operating at the following, wider range of DC supply voltages so long as the transient over-voltage protection diode is changed to suit:
- 7-25V, if only one hexadecimal switch and transistor output is used (the other switch must be set to zero).
- 7-15V, if two hexadecimal switches and transistor outputs are used.
- 9-15V, if the relay contacts are used.
Please advise any specific alarm and/or DC supply voltage requirements.
Qty 1 £175 + VAT
Qty 2 £155 + VAT
Qty 3 £138 + VAT
Qty 4 £128 + VAT
Qty 5 £122 + VAT
Qty 6 £118 + VAT
Stock available: 6
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