A detector comprises a detector base ( 1 ) and first and second detector elements ( 2 & 3 ) each having a respective electronic interface ( 2 a, 3 a ). The detector base ( 1 ) has electronic interfaces ( 1 a ) to the electronic interface ( 2 a, 3 a ) of each of the detector elements ( 2, 3 ), wherein at least one of the detector elements is constructed as a replaceable module ( 11 ).
1. A detector comprising:
first and second detector elements each having a respective electronic interface; and
a detector base having an electronic interface to the electronic interface of each of the detector elements, the detector base further having communication electronics, wherein at least one of the detector elements is constructed as a replaceable module, and wherein the communication electronics is configured to communicate information received from each detector element via the electronics interface of the detector base to a central control unit;
wherein the first detector element includes a first sensor for sensing a first physical property, and the second detector element includes a second sensor for sensing a second physical property which is different from the first physical property;
wherein the detector base analyzes signals output by each of the detector elements, thereby providing an increased fire detection capability; and
wherein the electronic interface of each detector element enables effective communication with the detector base, each electronic interface comprising a current-to-voltage converter, a buffer amplifier and a self-monitoring circuit.
2. A detector as claimed in claim 1 , wherein the at least one replaceable module is shaped and sized to complement an aperture formed in the detector base.
3. A detector as claimed in claim 2 , wherein the at least one replaceable module further comprises means for detachable connection to the detector base.
4. A detector as claimed in claim 3 , wherein the at least one replaceable module is provided with a partially-cut-out tab which is engageable with an apertured recess formed in the detector base, the tab and recess constituting said detachable connection means.
5. A detector as claimed in claim 2 , wherein the at least one replaceable module is provided with an upstanding apertured flange which is engageable with a projection provided at the peripheral front edge of the aperture formed in the detector base.
6. A detector as claimed in claim 1 , wherein the at least one replaceable module is provided with a projection or recess for slidable engagement with a complementary recess or projection provided on the detector base.
7. A detector as claimed in claim 1 , wherein the at least one replaceable module uses a common signalling system within the detector base.
8. A detector as claimed in claim 1 , wherein the first sensor senses CO, and the second sensor senses smoke, the detector constituting a fire detector.
9. A detector as claimed in claim 1 , wherein at least one of the detector elements is a toxin detector element.
10. A detector as claimed in claim 9 , wherein when both fire and toxin are sensed, a system is such as to generate an evacuation procedure that is different than that generated when fire is detected with no detection of a toxin.
11. A detector as claimed in claim 1 , wherein the first detector element is a replaceable module, and the second detector element is formed integrally with the detector base.
12. A detector as claimed claim 1 , wherein the electronic interface of the at least one replaceable module is adapted for communicating a signal indicative of a physical entity sensed by its sensor to the electronic interface of the detector base.
13. A detector as claimed in claim 1 , further comprising a flasher, a strobe unit or an IR detector.
14. A system comprising a detector as claimed in claim 1 and the central control unit, the central control unit being configured to treat information received from the detector as either complementary signals or independent signals.