First, there are two modes of operation: daylight mode, which is
entered if the mains failure occurs during the day, and night mode, if
the failure occurs at night.
U1 is a 7555 timer configured as an astable multivibrator, and it
generates 1MHz square waves used as clocks for the simulation; in real
life it would output 1Hz clocks.
S1 and S2 simulate a mains operated form "C" (SPDT) relay with the NC
contact connected to GND and the NO contact connected to +12. Thus,
when the mains is hot, the NO contact will made, forcing RST high and
resetting the circuit. If the mains should fail, however, the
armature will be released and the NO contact will be made, forcing RST
low and de-asserting the reset.
Assuming daylight mode, U5+ will have gone more positive than U5-,
forcing U5's output and U6A's PREset input high, which will also force
U6A-Q, U6B-D, and one of U3D's inputs high.
In the meantime, RST's having been high had disabled U2 by keeping it
in reset mode, but RST's going low when the mains failed forced U2 out
of reset, allowing it to count up.
U2 is used as a 2 hour timer for this application, and by accumulating
1 second clocks from U1, will reach 2 hours when it counts up to 7200.
7200 in Hexadecimal is 1C20, which in binary is 0001 1100 0010 0000.
U2 is a 14 stage ripple counter, and its outputs map to binary 7200
like this:
Q14 Q13 Q12 Q11 Q10 Q09 Q08 Q07 Q06 Q05 Q04 Q01
0 1 1 1 0 0 0 0 1 0 0 0 .
That means that when the count has reached 7200, Q13,Q12,Q11, and Q6
will be high and all the other outputs will be low.
U3A, U3B, and U3C are used to decode the output data from the counter,
with the output of U3C going high when the count reaches 7200.
When that happens,the output of U4C will go low, forcing U1 into reset
and stopping the clocks.
Also, remembering that we're working in daylight mode and that since
U6B-D is being held high, when U3C goes high it'll be used as the
clock input of U6B which will force U6B-Qbar permanently low until the
mains is restored and RST is once again asserted.
The falling edge of U6B-Qbar is differentiated by C3 and used as a
low-going trigger for U7, a 7555 timer used as a one-shot to provide
an output to the dialer.
In night mode, RST will go low when a mains failure occurs, but U5's
output will be low because no light has yet been detected.
RST going low at one of U4B's inputs forces U2's reset input low,
allowing U2 to count. as before, U2 will count up to 7200, but since
it's dark out we want to postpone the output to the dialer for 2 hours
after first light.
To do so, the counter's output is again decoded at 7200 clocks,
inverted by U4C, and sent to U1's reset input which will stop the
clock.
The circuit will remain in this condition until first light is
detected and U6A-Q goes high.
Since stopping the clock has kept the counter's outputs at 7200
binary, U3C's output will remain high and U6A-Q going high will cause
U3D to go high. That high-going edge will be differentiated by C1 and
used to reset U2.
When that happens, U3C's outputs will all go low, as will the output
of the decoder, forcing U4C's output high, enabling U1, allowing it to
start making clocks.
U2 will now start counting clocks again and when it gets to 7200 will
cause U1 to be reset, stopping the clocks, and also sent to the clock
input of U6B.
Now, since U6A-Q is high because first light has been detected, when
the clock input of U6B goes high U6B-Qbar will go low, triggering U7
and providing an output for the dialer.
So, in summary:
Daylight mode causes the counter to count to 7200 once and then
trigger the one-shot.
Night mode causes the counter to count to 7200, then freeze
until first light is detected when it'll be reset and will count to
7200 again before triggering the one-shot.
-- JF
Thanks very much John!
I will have a look though the description and have a play with ltspice today...its well beyond my design skills!
> First, there are two modes of operation: daylight mode, which is
> entered if the mains failure occurs during the day, and night mode, if
> the failure occurs at night.
> U1 is a 7555 timer configured as an astable multivibrator, and it
> generates 1MHz square waves used as clocks for the simulation; in real
> life it would output 1Hz clocks.
> S1 and S2 simulate a mains operated form "C" (SPDT) relay with the NC
> contact connected to GND and the NO contact connected to +12. Thus,
> when the mains is hot, the NO contact will made, forcing RST high and
> resetting the circuit. If the mains should fail, however, the
> armature will be released and the NO contact will be made, forcing RST
> low and de-asserting the reset.
> Assuming daylight mode, U5+ will have gone more positive than U5-,
> forcing U5's output and U6A's PREset input high, which will also force
> U6A-Q, U6B-D, and one of U3D's inputs high.
> In the meantime, RST's having been high had disabled U2 by keeping it
> in reset mode, but RST's going low when the mains failed forced U2 out
> of reset, allowing it to count up.
> U2 is used as a 2 hour timer for this application, and by accumulating
> 1 second clocks from U1, will reach 2 hours when it counts up to 7200.
> 7200 in Hexadecimal is 1C20, which in binary is 0001 1100 0010 0000.
> U2 is a 14 stage ripple counter, and its outputs map to binary 7200
> like this:
> Q14 Q13 Q12 Q11 Q10 Q09 Q08 Q07 Q06 Q05 Q04 Q01
> 0 1 1 1 0 0 0 0 1 0 0 0 .
> That means that when the count has reached 7200, Q13,Q12,Q11, and Q6
> will be high and all the other outputs will be low.
> U3A, U3B, and U3C are used to decode the output data from the counter,
> with the output of U3C going high when the count reaches 7200.
> When that happens,the output of U4C will go low, forcing U1 into reset
> and stopping the clocks.
> Also, remembering that we're working in daylight mode and that since
> U6B-D is being held high, when U3C goes high it'll be used as the
> clock input of U6B which will force U6B-Qbar permanently low until the
> mains is restored and RST is once again asserted.
> The falling edge of U6B-Qbar is differentiated by C3 and used as a
> low-going trigger for U7, a 7555 timer used as a one-shot to provide
> an output to the dialer.
> In night mode, RST will go low when a mains failure occurs, but U5's
> output will be low because no light has yet been detected.
> RST going low at one of U4B's inputs forces U2's reset input low,
> allowing U2 to count. as before, U2 will count up to 7200, but since
> it's dark out we want to postpone the output to the dialer for 2 hours
> after first light.
> To do so, the counter's output is again decoded at 7200 clocks,
> inverted by U4C, and sent to U1's reset input which will stop the
> clock.
> The circuit will remain in this condition until first light is
> detected and U6A-Q goes high.
> Since stopping the clock has kept the counter's outputs at 7200
> binary, U3C's output will remain high and U6A-Q going high will cause
> U3D to go high. That high-going edge will be differentiated by C1 and
> used to reset U2.
> When that happens, U3C's outputs will all go low, as will the output
> of the decoder, forcing U4C's output high, enabling U1, allowing it to
> start making clocks.
> U2 will now start counting clocks again and when it gets to 7200 will
> cause U1 to be reset, stopping the clocks, and also sent to the clock
> input of U6B.
> Now, since U6A-Q is high because first light has been detected, when
> the clock input of U6B goes high U6B-Qbar will go low, triggering U7
> and providing an output for the dialer.
> So, in summary:
> Daylight mode causes the counter to count to 7200 once and then
> trigger the one-shot.
> Night mode causes the counter to count to 7200, then freeze
> until first light is detected when it'll be reset and will count to
> 7200 again before triggering the one-shot.
> -- > JF
You will need some hysteresis around the "first light sensor", U5. The set and reset inputs of the CD4013 (U6A) do not like slow moving signals.
On Tue, 23 Oct 2012 05:59:05 -0500, "Rick" <rik...@bellsouth.net>
wrote:
>You will need some hysteresis around the "first light sensor", U5. The set >and reset inputs of the CD4013 (U6A) do not like slow moving signals.
---
Since the specs for the rising edge rates of SET and RESET are only
relevant when the time between SET or RESET and Q or Qbar is
important, the edge rate of U5's output doesn't matter.
What does matter is that at some point along U5's 0 to 12V output, U6A
will be forced to latch, and when that happens U6A will stay latched
until the mains goes hot.
On Tue, 23 Oct 2012 05:59:05 -0500, "Rick" <rik...@bellsouth.net>
wrote:
>You will need some hysteresis around the "first light sensor", U5. The set
>and reset inputs of the CD4013 (U6A) do not like slow moving signals.
---
Since the specs for the rising edge rates of SET and RESET are only
relevant when the time between SET or RESET and Q or Qbar is
important, the edge rate of U5's output doesn't matter.
What does matter is that at some point along U5's 0 to 12V output, U6A
will be forced to latch, and when that happens U6A will stay latched
until the mains goes hot.
-- JF
Hi John. What LDR do you recommend for the daytime detection V4?
> On Tue, 23 Oct 2012 05:59:05 -0500, "Rick" <rik...@bellsouth.net>
> wrote:
>>You will need some hysteresis around the "first light sensor", U5. The >>set
>>and reset inputs of the CD4013 (U6A) do not like slow moving signals.
> ---
> Since the specs for the rising edge rates of SET and RESET are only
> relevant when the time between SET or RESET and Q or Qbar is
> important, the edge rate of U5's output doesn't matter.
> What does matter is that at some point along U5's 0 to 12V output, U6A
> will be forced to latch, and when that happens U6A will stay latched
> until the mains goes hot.
> -- > JF
I know what you are saying; I have been bit by the problem before. You need a sharp rising signal on set/reset. Bread board it! If it does not work put the hysteresis in.
In order to have it trigger at what you want "first light" to be,
locate the circuit where it'll live and so that the LDR is exposed to
outdoor ambient light, then adjust the pot so that the wiper is at
the grounded end of the element.
Next, wait until first light and then adjust the pot until the
comparator's output just goes high.
>In order to have it trigger at what you want "first light" to be,
>locate the circuit where it'll live and so that the LDR is exposed to
>outdoor ambient light, then adjust the pot so that the wiper is at
>the grounded end of the element.
---
Oops...
Should read: ..."then adjust the pot so that the wiper is opposite the
grounded end of the element.
>In order to have it trigger at what you want "first light" to be,
>locate the circuit where it'll live and so that the LDR is exposed to
>outdoor ambient light, then adjust the pot so that the wiper is at
>the grounded end of the element.
---
Oops...
Should read: ..."then adjust the pot so that the wiper is opposite the
grounded end of the element.
-- JF
Thanks John,
I copied and pasted the above and converted the font to a fixed width but its still gibberish for some reason in word. I am using Lucinda console font which is apparently fixed width.
>In order to have it trigger at what you want "first light" to be,
>locate the circuit where it'll live and so that the LDR is exposed to
>outdoor ambient light, then adjust the pot so that the wiper is at
>the grounded end of the element.
---
Oops...
Should read: ..."then adjust the pot so that the wiper is opposite the
grounded end of the element.
-- JF
Thanks John,
I copied and pasted the above and converted the font to a fixed width but
its still gibberish for some reason in word. I am using Lucinda console
font which is apparently fixed width.
Can you describe the circuit for me?
cheers again!
Steve
Cant seem to source them in the UK for a reasonable price... will these do-
I will have to mount these remotely, say 20' away from the main circuit in order to get a good source of daylight. I may have to shade it from direct light too just in case a bright moonlight is interpreted as daylight....;-)
>In order to have it trigger at what you want "first light" to be,
>locate the circuit where it'll live and so that the LDR is exposed to
>outdoor ambient light, then adjust the pot so that the wiper is at
>the grounded end of the element.
---
Oops...
Should read: ..."then adjust the pot so that the wiper is opposite the
grounded end of the element.
-- JF
Thanks John,
I copied and pasted the above and converted the font to a fixed width but
its still gibberish for some reason in word. I am using Lucinda console
font which is apparently fixed width.
Can you describe the circuit for me?
cheers again!
Steve
Cant seem to source them in the UK for a reasonable price... will these do-
I will have to mount these remotely, say 20' away from the main circuit in
order to get a good source of daylight. I may have to shade it from direct
light too just in case a bright moonlight is interpreted as daylight....;-)
>I copied and pasted the above and converted the font to a fixed width but
>its still gibberish for some reason in word. I am using Lucinda console
>font which is apparently fixed width.
---
You shouldn't have to do any of that if you've got your newsreader
configured to display incoming posts in a fixed pitch font.
There's also a problem in that your newsreader isn't quoting properly,
making it impossible to reply to you without some really inconvenient
machinations on my end.
---
>Can you describe the circuit for me?
---
Yes, of course, but you should learn how to read pictures before
asking someone to waste a thousand words.
---
>Cant seem to source them in the UK for a reasonable price... will these do-
>In order to have it trigger at what you want "first light" to be,
>locate the circuit where it'll live and so that the LDR is exposed to
>outdoor ambient light, then adjust the pot so that the wiper is at
>the grounded end of the element.
>Next, wait until first light and then adjust the pot until the
>comparator's output just goes high.
>That's it...
You know, I have seen this "view with a fixed pitch font" from you
several times in the past, and in reflection each time was when you were
posting a circuit or a fix for someone.
So, essentially, Larkin is full of shit. You have been a greater
contributor to the group both in the spirit of the industry and the
spirit of the group topic.
He magically lost track of the circuits I posted too, but keeps
claiming I have never posted any, and keeps asking for more.
Don't know who put the burr under his saddle, but folks here seem to
bear the brunt of the resultant effect of his bent affect.
Reminds me of Rodney King. May he rest in piece. The idiots gave
Arafat the Nobel Prize that year.
>I copied and pasted the above and converted the font to a fixed width but
>its still gibberish for some reason in word. I am using Lucinda console
>font which is apparently fixed width.
---
You shouldn't have to do any of that if you've got your newsreader
configured to display incoming posts in a fixed pitch font.
There's also a problem in that your newsreader isn't quoting properly,
making it impossible to reply to you without some really inconvenient
machinations on my end.
---
>Can you describe the circuit for me?
---
Yes, of course, but you should learn how to read pictures before
asking someone to waste a thousand words.
---
>Cant seem to source them in the UK for a reasonable price... will these do-
---
No manufacturer?
No data sheet?
Question marks after the important specs?
I sure wouldn't go for it.
---
>I will have to mount these remotely, say 20' away from the main circuit in
>order to get a good source of daylight.
---
OK, if what you mean is the entire detector circuit.
---
>I may have to shade it from direct
>light too just in case a bright moonlight is interpreted as daylight....;-)
---
One bridge at a time...
-- JF
Right....have finally sieved the net for how to set up live mail to do fixed font and it now looks like a diagram!
Will go with the RS LDR then as at least it has data sheets.
Not sure how i can alter the way live mail posts to quote properly....will look into it.
Have now understood the main logic of the counting and logic circuit and congratulate you on your design skills! I like the way the cd4020 counts up and how you can filter the outputs at the required count.
<sand...@ntlworld.com> wrote:
>Right....have finally sieved the net for how to set up live mail to do fixed >font and it now looks like a diagram!
>Will go with the RS LDR then as at least it has data sheets.
>Not sure how i can alter the way live mail posts to quote properly....will >look into it.
>Have now understood the main logic of the counting and logic circuit and >congratulate you on your design skills! I like the way the cd4020 counts up >and how you can filter the outputs at the required count.
>Cheers
>Steve
---
Thanks. :-)
BTW, since it seems you want to build this thing, I emailed you a PDF
schematic of what should work in the real world.
For some reason it seems my photodump account is broken, so I also
posted it to abse in case anybody else is interested.
>>In order to have it trigger at what you want "first light" to be,
>>locate the circuit where it'll live and so that the LDR is exposed to
>>outdoor ambient light, then adjust the pot so that the wiper is at
>>the grounded end of the element.
>>Next, wait until first light and then adjust the pot until the
>>comparator's output just goes high.
>>That's it...
> You know, I have seen this "view with a fixed pitch font" from you
>several times in the past, and in reflection each time was when you were
>posting a circuit or a fix for someone.
> So, essentially, Larkin is full of shit. You have been a greater
>contributor to the group both in the spirit of the industry and the
>spirit of the group topic.
---
Thank you.
---
> He magically lost track of the circuits I posted too, but keeps
>claiming I have never posted any, and keeps asking for more.
> Don't know who put the burr under his saddle, but folks here seem to
>bear the brunt of the resultant effect of his bent affect.
> Reminds me of Rodney King. May he rest in piece. The idiots gave
>Arafat the Nobel Prize that year.
<sand...@ntlworld.com> wrote:
>Right....have finally sieved the net for how to set up live mail to do >fixed
>font and it now looks like a diagram!
>Will go with the RS LDR then as at least it has data sheets.
>Not sure how i can alter the way live mail posts to quote properly....will
>look into it.
>Have now understood the main logic of the counting and logic circuit and
>congratulate you on your design skills! I like the way the cd4020 counts >up
>and how you can filter the outputs at the required count.
>Cheers
>Steve
---
Thanks. :-)
BTW, since it seems you want to build this thing, I emailed you a PDF
schematic of what should work in the real world.
For some reason it seems my photodump account is broken, so I also
posted it to abse in case anybody else is interested.
-- JF
Many thanks John for all your effort! You can email me direct by replacing the first part of the email address with r.p.mcmurphy although i have the pdf you posted yesterday on abse. I will get the parts ordered and report back on any problems. Can i confirm the output pulse is a short pulse of +ve that i can use to open normally-closed relay contacts?
<sand...@ntlworld.com> wrote:
>Right....have finally sieved the net for how to set up live mail to do >fixed
>font and it now looks like a diagram!
>Will go with the RS LDR then as at least it has data sheets.
>Not sure how i can alter the way live mail posts to quote properly....will
>look into it.
>Have now understood the main logic of the counting and logic circuit and
>congratulate you on your design skills! I like the way the cd4020 counts >up
>and how you can filter the outputs at the required count.
>Cheers
>Steve
---
Thanks. :-)
BTW, since it seems you want to build this thing, I emailed you a PDF
schematic of what should work in the real world.
For some reason it seems my photodump account is broken, so I also
posted it to abse in case anybody else is interested.
-- JF
Many thanks John for all your effort! You can email me direct by replacing
the first part of the email address with r.p.mcmurphy although i have the
pdf you posted yesterday on abse. I will get the parts ordered and report
back on any problems. Can i confirm the output pulse is a short pulse of
+ve that i can use to open normally-closed relay contacts?
Cheers
Steve
Hi John,
one other question is the schematic correct on abse regarding the cd4082, should this be cd4081?
<sand...@ntlworld.com> wrote:
>Many thanks John for all your effort! You can email me direct by replacing >the first part of the email address with r.p.mcmurphy although i have the >pdf you posted yesterday on abse. I will get the parts ordered and report >back on any problems. Can i confirm the output pulse is a short pulse of >+ve that i can use to open normally-closed relay contacts?
>Cheers
>Steve
---
Vcc, actually, but yes.
With a 50mA load, the 7555 drops about 2V across its output, so if you
choose a relay with a coil current less or equal to that, a 7555
should work OK.
Farnell has them in stock, and don't forget to put a diode (a
1N914/1N4148 will do) across the coil, with the cathode connected to
the pin going to U7-3.
Just as an aside, I think you're going to have a tough time sourcing
K1 if it's got to have a 240VAC coil and signal level contacts, so one
solution would be to use a lower voltage DC coil relay and drive it
from a full-wave bridge fed by a capacitor in series with the mains,
like this: (Don't forget the fixed-pitch font ;)
If you were to use the 24V coil version of the 12V OMRON relay, that
would be the G5V-1-DC24, which has a 3840 ohm coil and a coil current
of 6.25mA with 24V across the coil.
Sooo...
Here's the fun part; how do we figure out the value of the cap?
Since the diode drops are insignificant, we can look at the circuit
like this:
Since the coil is seeing full-wave rectified AC instead of pure DC,
its RMS value must be equal to 24VDC, which means its peak value is
24VDC * sqrt2 ~ 34VP.
We also know that the coil will be drawing 6.25mA so, since in a
series circuit the current is everywhere the same, that 6.25mA must
also pass through the cap.
For that to happen, the impedance of the entire circuit must be:
E 240V
Z = --- = ---------- = 38400 ohms.
I 0.00625A
Now, since:
Z² = X² + R²
and we want to solve for the capacitance, we first need to get the
capacitive reactance, so we rearrange and solve for X:
Xc = sqrt (Z² - R²) ~ 38208 ohms.
Then, to get the capacitance:
1 1
C = ------------ = -------------------------- ~ 8.3E-8F
2pi f (Xc) 6.28 * 50Hz * 38208 ohms
That's 83nF.
82nF is the closest standard value, and Panasonic has a nice part,
ECQ-E6683JF:
>>Many thanks John for all your effort! You can email me direct by replacing >>the first part of the email address with r.p.mcmurphy although i have the >>pdf you posted yesterday on abse. I will get the parts ordered and report >>back on any problems. Can i confirm the output pulse is a short pulse of >>+ve that i can use to open normally-closed relay contacts?
>>Cheers
>>Steve
>---
>Vcc, actually, but yes.
>With a 50mA load, the 7555 drops about 2V across its output, so if you
>choose a relay with a coil current less or equal to that, a 7555
>should work OK.
>Farnell has them in stock, and don't forget to put a diode (a
>1N914/1N4148 will do) across the coil, with the cathode connected to
>the pin going to U7-3.
>Just as an aside, I think you're going to have a tough time sourcing
>K1 if it's got to have a 240VAC coil and signal level contacts, so one
>solution would be to use a lower voltage DC coil relay and drive it
>from a full-wave bridge fed by a capacitor in series with the mains,
>like this: (Don't forget the fixed-pitch font ;)
>If you were to use the 24V coil version of the 12V OMRON relay, that
>would be the G5V-1-DC24, which has a 3840 ohm coil and a coil current
>of 6.25mA with 24V across the coil.
>Sooo...
>Here's the fun part; how do we figure out the value of the cap?
>Since the diode drops are insignificant, we can look at the circuit
>like this:
>Since the coil is seeing full-wave rectified AC instead of pure DC,
>its RMS value must be equal to 24VDC, which means its peak value is
>24VDC * sqrt2 ~ 34VP.
>We also know that the coil will be drawing 6.25mA so, since in a
>series circuit the current is everywhere the same, that 6.25mA must
>also pass through the cap.
>For that to happen, the impedance of the entire circuit must be:
> E 240V
> Z = --- = ---------- = 38400 ohms.
> I 0.00625A
>Now, since:
> Z² = X² + R²
>and we want to solve for the capacitance, we first need to get the
>capacitive reactance, so we rearrange and solve for X:
OMRON reports that if their G5V-1 relays are operated with the coil
energized for a long time and no switching is done, the heat from the
coil affects the insulation and causes a film to be deposited on the
contacts which can lead to problems.
