5 second reset?
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From: shbazjinkens on 13 May 2010 01:17 On May 12, 11:18 am, jodleren <sonn...(a)hot.ee> wrote: > Hi all > > I need to hold Reset on a PLC for some time. > To do so I'd like to use a crystal and chip, not a condensator or > something. > > I looked at the 4060, which has an onboard option for a crystal, but I > am a little uncertain about how the counter works - I need to divide > by at least 160000 (or, say 2 in power of 17 or 18 is just fine for > me). > > Is there a single chip available that can do most of it? > > Present power is either 5 or 12V. > > Sonnich Is there some reason that the PLC logic can't be modified to accommodate your needs?
From: Winston on 13 May 2010 01:57 On 5/12/2010 9:00 PM, George Herold wrote: (...) > Seems like someone must sell a clock chip/package that puts out one > pulse per second? Then you just have to count to 300. 'course I > don't know of any such device. The electric company provides pretty accurate 60 Hz for that divide - by - 300 circuit. It'll cost you a small transformer, a couple diodes and a resistor. --Winston <-- Or maybe an optoisolator, a cap and a couple diodes
From: jodleren on 13 May 2010 06:20 On May 13, 8:17 am, shbazjinkens <rossmoff...(a)gmail.com> wrote: > On May 12, 11:18 am, jodleren <sonn...(a)hot.ee> wrote: > > > > > Hi all > > > I need to hold Reset on a PLC for some time. > > To do so I'd like to use a crystal and chip, not a condensator or > > something. > > > I looked at the 4060, which has an onboard option for a crystal, but I > > am a little uncertain about how the counter works - I need to divide > > by at least 160000 (or, say 2 in power of 17 or 18 is just fine for > > me). > > > Is there a single chip available that can do most of it? > > > Present power is either 5 or 12V. > > >Sonnich > > Is there some reason that the PLC logic can't be modified to > accommodate your needs? Dont know yet. The manufacturer recommends so for this 15+ years old TNS PLC. Sonnich
From: ian field on 13 May 2010 09:19 "George Herold" <gherold(a)teachspin.com> wrote in message news:c87ece62-cab2-44ea-8ef3-6377002999f7(a)e35g2000yqm.googlegroups.com... On May 12, 12:18 pm, jodleren <sonn...(a)hot.ee> wrote: > Hi all > > I need to hold Reset on a PLC for some time. > To do so I'd like to use a crystal and chip, not a condensator or > something. > > I looked at the 4060, which has an onboard option for a crystal, but I > am a little uncertain about how the counter works - I need to divide > by at least 160000 (or, say 2 in power of 17 or 18 is just fine for > me). > > Is there a single chip available that can do most of it? > > Present power is either 5 or 12V. > > Sonnich Seems like someone must sell a clock chip/package that puts out one pulse per second? Then you just have to count to 300. 'course I don't know of any such device. Rip the PCB out of a quartz analogue travel clock and use a couple of forward biased diodes and a dropper resistor for its supply.
From: John Fields on 13 May 2010 12:35
On Wed, 12 May 2010 09:18:15 -0700 (PDT), jodleren <sonnich(a)hot.ee> wrote: >Hi all > >I need to hold Reset on a PLC for some time. >To do so I'd like to use a crystal and chip, not a condensator or >something. > >I looked at the 4060, which has an onboard option for a crystal, but I >am a little uncertain about how the counter works - I need to divide >by at least 160000 (or, say 2 in power of 17 or 18 is just fine for >me). --- The 4060 is a 14 stage binary ripple counter with an on-board oscillator circuit. It works by progressively dividing the input clock by succesively higher powers of 2 up to a maximum of 16383 clocks, when all of its Q outputs will be high. Then, on the 16384th clock, it'll reset and all the outputs will go low, starting a new count cycle. --- >Is there a single chip available that can do most of it? --- I don't think so, since it sounds like you'll be using a 32768Hz crystal for the oscillator and you want a 5 second delay. That's 163840 clocks, and a 4060 can only count up to 16383 until it overflows, but you can easily do it using a couple of 4060s or a 4060 and a 4024, plus some kind and some glue logic in either case. --- >Present power is either 5 or 12V. --- OK. I'm assuming you've got a pushbutton switch somewhere that you want to press momentarily to put the PLC in RESET, and then 5 seconds later have the timer release the RESET. Right? If so, let me know and I'll post a schematic for you here. BTW, what does the PLC want to see as a RESET signal? |