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Also DS from where negativ to pass ? (Answer : B4) ... DS's in circuit 1A or more Current to pass. 1A current is for push-buton or to be too much.
__________________ I am sorry my friends... For my English. | |||
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| Now I understand. The coil current of DS is too much for the B4 contacts. Here is a simple solution and it has the additional advantage that D5 is not required.
__________________ Len Last edited by ljcox; 4th January 2008 at 02:51 AM. | |
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__________________ I am sorry my friends... For my English. | ||
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| That's good. It is possible to include B1 and B4 in the error logic. It will require the following extra components:- 1 relay, 3 diodes, 2 capacitors & 2 resistors. The resistors and capacitors are necessary to increase the release time of relays X4 and E by a small amount. This necessary to ensure that any operated relays (ie. X1, X2 or X3) will release before X4 or E release. I'll leave it to you to work out how to do this - if you wish. Let me know if you want to see my method and I'll post it for you.
__________________ Len Last edited by ljcox; 5th January 2008 at 01:08 AM. | |
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| Firstly , Error Relay Coil parallel appr. 4700uF Condensator required.
__________________ I am sorry my friends... For my English. | |
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What is the resistance of the relay coil?
__________________ Len | ||
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(appr.2200-4700uF--> For 5sn (appr.) delay time to get).
__________________ I am sorry my friends... For my English. | ||
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| Here is the circuit with additional error logic so that circuit will be reset if B1 or B4 are pressed out of sequence. I have changed the name of relay E to RS as it now does a reset function even when the correct sequence of buttons is pressed. The release time of RS (determined by C2) allows time for the release of any operated relays.
__________________ Len | |
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| What a mess relay logic can quickly become. I was always amazed that the telephone companies switching relay logic worked as well as it did. Seems to me I read an early 'computer' was built using relay logic during or right after WW2. Relays are still very useful. They have great isolation (input/output) and can be sized for crazy voltages and current levels. So they are still very viable as a final control element, but as a logic solver? Get real, a simple micro-controller driving the door solenoid via a Mosfet is so much simpler, better, cheaper and programmable that it's painful to even have to explain. Lefty
__________________ Measurement changes behavior | |
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| You're overlooking one distinct advantage relay logic has over electronic logic. In its quiescent state, it consumes ZERO energy. Therefore it could be run from a battery that would only have to be replaced every 2 ~ 3 years. How long would an electronic one run on a battery? The CMOS one I posted above may last quite while (as it is a combinational lock, there is no oscillator running or other power consuming items), but I'm not too sure about a PIC version. Besides, the op specified a relay version - I don't know why - perhaps it is a school project. The first "computer" - the Colossos - was built in England during WW2 to assist in decoding German cyphers was partly electronic and partly relay logic.
__________________ Len Last edited by ljcox; 6th January 2008 at 09:56 AM. | |
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__________________ I am sorry my friends... For my English. | |
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| Ok... Now identically for X4 Relays delay time required.(approx. 1-3sn)...
__________________ I am sorry my friends... For my English. | |
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Britain had a massive world lead in computers and all from a single guy who worked for the Post Office, and 'stole' all the parts to build it! I'm sure I read somewhere a bit back that they have built a reconstruction of it now?. | ||
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He [Tommy Flowers] actually spent a £1000 of his own money as well as the 'borrowed' bits to build the first one, which after many years the Govt paid him back.. The other 9 Collososii were built with Govt funding. Mr W Churchill at the end of the war ordered all the 10 to be dismantled and the documentation to be destroyed.. he was concerned it would fall into the hands of the USSR. The working reconstruction was shown working on a recent TV program...
__________________ Eric "Good enough is Perfect" PIC tutorials: Gramo's: www.digital-diy.net/ Bill's: www.blueroomelectronics.com/ | ||
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| 1N4007 required? No This is a standard technique used to increase the release time of relays. But a diode is not used in that position as it is not necessary.
__________________ Len Last edited by ljcox; 6th January 2008 at 10:02 PM. | |
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