Discuss Fire alarms installation and testing in the Security Alarms, Door Entry and CCTV (Public) area at ElectriciansForums.net
I have already listed resistance and voltage reading you should expect, using a multi meter..How would i test the circuit.
And what sort of reading i am going to get?
Gasp!!How would i test the circuit.
And what sort of reading i am going to get?
The resistor is the most common method, using 470 call points, but as you stated Tel ...Active eol units are on the market, but less common now as most have been taken off the market with new EN ruling.fine if the eol is a pure resistor. some are more complex and as such can't be read on a multimeter. hoewver it's easy to operate a call-point and get the expected 470Ω .
They were very simple but a clever idea, using binary code depending on the order of 4 switches. you could control 15 separate operations down 4 cables.....this is now the basic principle of cambus and addressable alarm systems using 8 switches to select the binary code, but now it can be sent on a 2 wire power line, with over 250 separate operations.Early SWL systems on cranes (pre pre CanBus) had similar arrangement for assessing conditions,three interlocks,or limit switches with varying resistor values,basic control board determined what was happening by reading resistances or combination of,O/C or full continuity reading as a separate fault. Cannot say i miss monkey clambering up a 300' strut jib with a gas soldering iron and a bag of assorted resistors...:willy_nilly:
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