Electrical timer that does this?

Annoying - something seems to have lost my last post. Anyway, I said much the same thing.

74HCT4060 (or similar). Set it up with RC timing, to clock at 0.5Hz or so. Add a RC network from VCC to MR to ensure that when the supply comes up it resets cleanly (say 10uF and 10K). Add a diode from RS to bit 14 - so that when bit 14 goes high, it stops the clock. And from the same pin, a resistor, to an NPN transistor to drive the relay.
Reply to
Ian Stirling
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I can see the post. We basically came up with the same design, with a slightly different suggested implementation!

Reply to
Andrew Gabriel

Ah, it's plusnet...

Sigh.

I don't like mains driven clocks, for assorted reasons, mainly squaring up while eliminating noise is annoying, not to mention the input protection stuff.

And the frequency stability is only really good for clocks, as its only great virtue is to be 50Hz over 24h, but can vary by as much as a percent locally.

Reply to
Ian Stirling

I'll have a go with a 74hct4060 then (never used one before so that'll be fun!)

Reply to
dave

I think it may be obsolete. Luckily I've still got a few. I've not found a suitable replacement.

Reply to
Dave Plowman (News)

I built the control for a simple wrapping machine with the logo, my last project was for monitoring a ink viscosity controller for 12 ink tanks for faults. Monitoring relay output times for an elongated or excessive multiple outputs. This then isolated a particular channel and then flashed a fault code up on a single red fault lamp. This last project grew too big for a logic controller, I had to go for a full PLC (Allen Bradley Micrologix)

I think you are correct on the serial side, purley for upload/download. AFAIAK the ASi bus will allow a second controller to run as remote I/O within the main software (I think the remote unit can also be running its own too)

HTH

Reply to
Tim Morley

Thanks Tim.

As a matter of interest, what was the limitation of the logic controller that prompted you to move to the PLC?

I haven't studied the Micrologix in detail yet, but it would appear at first sight that there is more analogue functionality and faster execution as well as more storage etc. Are these the main aspects that are important? I note that the modules themselves are 50%+ more expensive and programming software £300+ as well - obviously not a lot in a commercial setting. I couldn't find any documentation other than a product manual and installation instructions - nothing on the functional capabilities and programming. Is this part of the software documentation?

Any insight that you can give would be helpful.

many thanks

Reply to
Andy Hall

I know this is getting a little off topic now, but I feel we can keep it here for now ;)

The reason I jumped to a plc was the number of timers I required for the project, I think from the top of my head I used about 40! The documentation for writing the software is in with the RS Logix 500 software itself; BUT it is assumed that you can write ladder software anyway. Steep (vertical) learning curve if you have never written ladder before (even if you have seen other peoples ladders!). I had actually been on a course at Siemens in Manchester for programming their older S5 plcs ( £2000, paid for by work!) this gave me a good foundation; BUT all manufacturors go about things in their own way. There is a book by Allen Bradley which is excellent for starters (have a look at rswww.com , RS Stock no: 191-7038, price £13) "This is a beginners guide to programmable logic controllers based on the Micrologix 1000. It takes the reader through the basics of designing a control system and programming. The book includes step-by-step application examples and common programming techniques. ". You may be able to get from other sources.

Hope this helps, feel free to ask again ;)

Reply to
Tim Morley

I don't see a problem there.

OK...

I have looked at it briefly in the past, but haven't written them.

I'll perhaps get that next time I place an RS order.

However, considering the cost of the software, it might be a better option to go for one of the bus types of controller like the Moeller Easy800. It may even be possible to make a hierarchy of them with outputs of one to inputs of another.

I think I'll do a comparison of what each contains in terms of types and quantities of functional blocks and see where that takes me.

Many thanks and I well might

Reply to
Andy Hall

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