Whitestone Posted March 24, 2007 Posted March 24, 2007 How compatable are different brands of mcp and heat/smoke detectors? From what I can make out, the older mcps have no resistor and either cause an open or closed circuit when activated. The later ones have resistors of either 470 0hms or 680 ohms. When triggered is this resistance connected across the positve and negative on the radial circuit? I have spoken to Alto support who tell me that Menvier mcps are not compatible with Alto despite being made by the same company. Why is this? Can anybody recommend a web site or book that explains the basic circuitry. Althogh competent in testing systems my knowledge of the working princples is somewhat patchy. Many thanks
luggsey Posted March 24, 2007 Posted March 24, 2007 How compatable are different brands of mcp and heat/smoke detectors?From what I can make out, the older mcps have no resistor and either cause an open or closed circuit when activated. The later ones have resistors of either 470 0hms or 680 ohms. When triggered is this resistance connected across the positve and negative on the radial circuit? I have spoken to Alto support who tell me that Menvier mcps are not compatible with Alto despite being made by the same company. Why is this? Can anybody recommend a web site or book that explains the basic circuitry. Althogh competent in testing systems my knowledge of the working princples is somewhat patchy. Many thanks You can't go far wrong by using the same make panel and detectors/mcp's. There are so many issues with using different makes it does not make sense to advise you otherwise IMHO. ----------------------------------------------------------------------------------------------------------------------------------- Life is like a box of chocolates, some bugger always gets the nice ones! My Amateur Radio Forum
Whitestone Posted March 25, 2007 Author Posted March 25, 2007 You can't go far wrong by using the same make panel and detectors/mcp's.There are so many issues with using different makes it does not make sense to advise you otherwise IMHO. Thanks for your advice Any suggestions for further reading? Also what is meant by a supressed sounder? Peter
luggsey Posted March 25, 2007 Posted March 25, 2007 Thanks for your adviceAny suggestions for further reading? Also what is meant by a supressed sounder? Peter Try the sites of Gent, Morley, System Sensor, Appolo, Hochiki, Protec, etc. Suppressed sounder has back EMF damping diodes fitted to it, only found on electromagnetic types. (Bells) ----------------------------------------------------------------------------------------------------------------------------------- Life is like a box of chocolates, some bugger always gets the nice ones! My Amateur Radio Forum
Whitestone Posted March 25, 2007 Author Posted March 25, 2007 Try the sites of Gent, Morley, System Sensor, Appolo, Hochiki, Protec, etc.Suppressed sounder has back EMF damping diodes fitted to it, only found on electromagnetic types. (Bells) Would using a bell without a supressor cause damage to the panel?
luggsey Posted March 25, 2007 Posted March 25, 2007 Would using a bell without a supressor cause damage to the panel? Short answer is possibly, it's not the only reason they are fitted with diodes, one is for back EMF and one is for masking the coil resistance from the panels monitoring circuit, if you don't fit them there will be a fault even if you fit the EOL device. ----------------------------------------------------------------------------------------------------------------------------------- Life is like a box of chocolates, some bugger always gets the nice ones! My Amateur Radio Forum
esp-protocol Posted March 25, 2007 Posted March 25, 2007 How compatable are different brands of mcp and heat/smoke detectors?From what I can make out, the older mcps have no resistor and either cause an open or closed circuit when activated. The later ones have resistors of either 470 0hms or 680 ohms. When triggered is this resistance connected across the positve and negative on the radial circuit? I have spoken to Alto support who tell me that Menvier mcps are not compatible with Alto despite being made by the same company. Why is this? Can anybody recommend a web site or book that explains the basic circuitry. Althogh competent in testing systems my knowledge of the working princples is somewhat patchy. Many thanks Very briefly, the older call points you refer to are no longer compatible with "modern" compliant equipment. The call points worked like a light switch and simply put a short circuit between pos and neg. The panel would see a large current flow for that zone and would initiate a fire condition. There was an amendment to the 1988 BS (I think) that said that effectively you have to monitor cables for short circuit, and cause a fault condition rather than a fire condition. So panels and call points changed to introduce a resistance across the switch rather than a short circuit. Most commonly these resistance values were 470 or 680 ohm, depending on the manufacturer. Most panels are pretty tolerant and you can generally get away with using either type of call point but its always best to check with the manufacturer for their recommended "firing" resistance. After that you should be able to go to any non addressable call point manufacturer and use whatever you like - KAC probably most common but there are other and (IMO) better call points around. As luggsey said, Apollo is a good site and I think the ACT website gives a lot of fault finding and technical info also...
Whitestone Posted March 26, 2007 Author Posted March 26, 2007 Very briefly, the older call points you refer to are no longer compatible with "modern" compliant equipment. The call points worked like a light switch and simply put a short circuit between pos and neg. The panel would see a large current flow for that zone and would initiate a fire condition.There was an amendment to the 1988 BS (I think) that said that effectively you have to monitor cables for short circuit, and cause a fault condition rather than a fire condition. So panels and call points changed to introduce a resistance across the switch rather than a short circuit. Most commonly these resistance values were 470 or 680 ohm, depending on the manufacturer. Most panels are pretty tolerant and you can generally get away with using either type of call point but its always best to check with the manufacturer for their recommended "firing" resistance. After that you should be able to go to any non addressable call point manufacturer and use whatever you like - KAC probably most common but there are other and (IMO) better call points around. As luggsey said, Apollo is a good site and I think the ACT website gives a lot of fault finding and technical info also... Many thanks, that makes a lot of sense. I notice that the Alto mcps have a printed circuit board fitted with more than just a resistor any idea what components these are and is this why Alto tech support say that no other mcp should be used? Have you the address for the ACT site you mention? Peter
esp-protocol Posted March 26, 2007 Posted March 26, 2007 http://www.actmeters.com/ It's mostly security orientated but its still an interesting read. These Alto call points, are you sure they're no addressable ??
Whitestone Posted March 26, 2007 Author Posted March 26, 2007 http://www.actmeters.com/It's mostly security orientated but its still an interesting read. These Alto call points, are you sure they're no addressable ?? That could be the answer. The panel is not addressable but perhaps they only supply one type of mcp that is common to all their panels.
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