Question on the 4046

[Harry Dalek]

I am close to trying to sync my monitor i am just wondering if any one has tried Steves pulse cleaning shaping ideas in these circuits ?
i am also just wondering since it must be a few years old now things tend to be updated ,i know its our job to experiment but apart from Holtzmans go at syncing there really isn't that much to choose from ...for newies to this which i am really to as i have never really tried this on a mechanical monitor .

Some ideas i have which i am wondering about for a start in this circuit as i always like changing things to whats in the junk box ..

The Opto fork this could be replaced with a led and LDR ,i used to think the ldr was sluggish but as again Holtzman has shown it is more than fast enough.

i am also wondering due tothe size of the LDR over the light S transistor or diode would this help in it seeing the light pulses better ...i can see a wobble in say a nipkow disk causing a missing pulse if a hole is half seen by the transistor...mmmm

Now the end part of the circuit i have been thinking about also ....Now i am just using LM317 to control my motor speed the Pot to control the speed is of cause manual i havebeen toying with the idea of instead of using the mosfet part of the circuit why not control the LM317 via the trim pot Automaticity,i started off thinking of hooking up a LDR to it this would change thevoltage out ...and you could fine tune it with a trim pot in series ....then i was thinking why just do the same via pulses ...think it would work

Just some ideas

Also thinking Of doing away with the PLL using 2 555 timers the first for a monostable this for the opto fork ...the second a astable the sync into pin 5 output into pin 5 of the monostable output of the monostable to what ever you want to drive your motor.

Now i would be interested if anyone thinks it might work or shoot me down in flames i don't care ,what matters is what works

advice is always appreciated!

[Steve Anderson]

A LM317 could be used for motor control, but there are a few problems I see initially...

1) Using the 'control' pin of the '317 as its input the output is 1.25V higher which means unless you have a negative supply and arrange things to suit you cannot shut off the voltage to the motor completely.

2) The '317 is a supply of current, whereas the MOSFET is a drain/sink of current., the topology of the circuit would have to be changed quite a bit. However this would compensate for the major difference that the MOSFET is an inverter, the '317 a follower.

3) There is a current out of the control pin of the '317 that a MOSFET does not have, this would require quite a redesign of the loop filter components.

4) The output voltage would be limited to 1.25V more than the supply of the 4046, 15V + 1.25V, so you couldn't control a 24V (or more) motor.

These are not insurmountable, but quite a task and a complete project in itself.

As for the monostable idea, I don't quite grasp your concept.

Steve A.

[Harry Dalek]

A LM317 could be used for motor control, but there are a few problems I see initially...

1) Using the 'control' pin of the '317 as its input the output is 1.25V higher which means unless you have a negative supply and arrange things to suit you cannot shut off the voltage to the motor completely.

2) The '317 is a supply of current, whereas the MOSFET is a drain/sink of current., the topology of the circuit would have to be changed quite a bit. However this would compensate for the major difference that the MOSFET is an inverter, the '317 a follower.

3) There is a current out of the control pin of the '317 that a MOSFET does not have, this would require quite a redesign of the loop filter components.

4) The output voltage would be limited to 1.25V more than the supply of the 4046, 15V + 1.25V, so you couldn't control a 24V (or more) motor.

These are not insurmountable, but quite a task and a complete project in itself.

As for the monostable idea, I don't quite grasp your concept.

Steve A.

Hi steve

Thanks for the advice..the Lm317 idea was mainly a stepping stone from manual control idea .

Oh well its good to know not to go down that path if you think its harder than the original circuit .

I was thinking on the 555s one is used for the opto fork the other is in sync with the video sync pulse this Astable in sync with the video is then fed to the pin 5 control of the monostable 555 more than likely wrong but was hoping both would be in phase with each other then .

[gary]

I suspect a couple of 555s in BIstable mode would make a a good sync motor control circuit, but the only real advantage over 4 gen purp npn transistors configured in bistable mode would possibly be the inherent pulse signal conditioning they provide.

[Harry Dalek]

I suspect a couple of 555s in BIstable mode would make a a good sync motor control circuit, but the only real advantage over 4 gen purp npn transistors configured in bistable mode would possibly be the inherent pulse signal conditioning they provide.

Hi gary

I was looking in my junk box and i have 2 4046pll and 3 lm565pll .....100 555 timers.

I was just remaking my power supply for the only reason i was just short of 48 line speed on the large drum its just out of sync by the looks of it so a few more volts should do it .

But anyway no need to go transistors i have too many 555's ,thats interesting i didn't think of a bistable idea .

I think since i have the pll's handy i may as well use it and from what i have been reviewing on the forum some sort of pulse cleaning for the opto fork idea with steve theres 2 ideas and a 555 i have read another as well .

What do you use gary on your monitors just the club circuit?

[gary]

I've used every possible circuit that you could think of over the years with varying degrees of success. With the bistable approach there is very little that can go wrong and when it does it is relatively easy to debug. The 4046 circuit works well when it works but it can be a right ornery critter to debug when it doesn't, and I, and I get the feeling most others, don't know why.

The only thing that I have modified with the stock standard 4 transistor circuit is I like to condition the pulses such that they (sync and opto) are similar in nature - width and magnitude wise. That seems to make the circuit pretty much fool proof. LOL I use 555s to do that, hence I've been meaning to get around to just using the 555s in bistable mode, just haven't done so yet.

[Harry Dalek]

I've used every possible circuit that you could think of over the years with varying degrees of success. With the bistable approach there is very little that can go wrong and when it does it is relatively easy to debug. The 4046 circuit works well when it works but it can be a right ornery critter to debug when it doesn't, and I, and I get the feeling most others, don't know why.

The only thing that I have modified with the stock standard 4 transistor circuit is I like to condition the pulses such that they (sync and opto) are similar in nature - width and magnitude wise. That seems to make the circuit pretty much fool proof. LOL I use 555s to do that, hence I've been meaning to get around to just using the 555s in bistable mode, just haven't done so yet.

Hi Gary i find the bistable idea very interesting ,if i got it right you use the opto fork and the sync for the set and reset inputs if so boy thats simple ...i really like that idea .
I had a go at the 4046 many years ago as i recall i found it a harder PLL ic than the 565PLL.

So you made your flip flops out of transistors ,i did that too many years ago but never have since i played around with the 555....i found when i made the bistable 555 the resistor settings were a bit fussy to get it to reset best to put a trim pot in save the experimenting.

So you use a timer to adjust the pulse width before the bistable ...thats some thing i need to think about to then.

I think i will try your idea simple always is the best more than likly try the other on a circuit board just to see since i have the parts but from what you say i think your idea is better .

[gary]

It's a pretty old tried and proven circuit, note, however, that it doesn't give you any sort of frame lock as the 4046 cct tends to. Still, I like it as it is pretty easy to get going and you can easily trace all the signals for debugging.

See newsletter volume 14 number 3 for more info.

[Harry Dalek]

It's a pretty old tried and proven circuit, note, however, that it doesn't give you any sort of frame lock as the 4046 cct tends to. Still, I like it as it is pretty easy to get going and you can easily trace all the signals for debugging.

See newsletter volume 14 number 3 for more info.

Hi Gary

Just reading the newsletter i think i would try it via a 555 so i don't think i would copy the circuit fully apart from the idea block diagram...looks pretty easy but i bet theres a bit of fine tuning to it ...Oh well its a start to try ,thanks for the info .

[gary]

Hi Gary

Just reading the newsletter i think i would try it via a 555 so i don't think i would copy the circuit fully apart from the idea block diagram...looks pretty easy but i bet theres a bit of fine tuning to it ...Oh well its a start to try ,thanks for the info .

No there isn't much in the way of fine tuning, that's why I like it. Built exactly as described works well for a wide range of motors. the only thing I have ever had to modify is the smoothing capacitor - which you have to do for the 4046 cct too. I have used it with cassette motors up to 1/2 horsepower motors.

I recommend using the 555s to "square" up the pulses and to give them the same duty cycle, but I see that as part of the sync source circuitry than the motor sync.

But yes,as I said before, you don't need to use discrete transistors for the bistables, but you know it'll work if you do

[Harry Dalek]

Hi i have been tossing up should i make Garys idea or the clubs ...
On my power supply board i had space for one and i really wanted to try both since i have the parts ,so i have been thinking about it and am going to do both on one new board i will reuse the Mosfet motor drive and just switich between the bistable and the PLL to drive the motor and see ...only doing this to learn so if one does not work least one should no great loss..bit of luck both might .

Since i have great respect for Steves and he's help with circuits i have used hes LM311 ad on ...i have all the parts just in my junk box so i may as well use them and learn .

If you see this steve i have replaced the Mosfet with a irf630 but i have made the circuit so its easy to remove and replace if it does not work .

I rather the bistable circuit just because i can understand the working better ,so thats going to be next ad on to the board ,i will more than likly use 2 monstable 555's to adjust the pulse width of the opto fork and and the sync and feed these to a bistables set reset inputs then a switch to feed to the mosfet part of the 4046 circuit that drives the motor ,so i can reuse that .

[Steve Anderson]

...See newsletter volume 14 number 3 for more info.

Although I have perused the back-issue CD somehow I missed this. It's intuitive in it's operation and de-buggering is simple with the exception perhaps of 'R' and 'C' in the diagram. I'm not quite sure of the function of the diode, but presumably it's required.

Instead of discrete trannies any set-reset bistable would function. To be honest I find this more promising than the usual 4046 arrangement, but I haven't tried either as yet. This is still a PLL, make no mistake, the motor/disk/photo-detector comprise the equivalent of a VCO, exactly the same as the more familiar 4046 arrangement.

Now with a 'missing pulse' input and a 'missing pulse' feedback there is a chance that it should achieve frame-lock also. This all hangs on the loop gain, damping and mechanical elements (as ever).

Steve A.

[Harry Dalek]

...See newsletter volume 14 number 3 for more info.

Although I have perused the back-issue CD somehow I missed this. It's intuitive in it's operation and de-buggering is simple with the exception perhaps of 'R' and 'C' in the diagram. I'm not quite sure of the function of the diode, but presumably it's required.

Instead of discrete trannies any set-reset bistable would function. To be honest I find this more promising than the usual 4046 arrangement, but I haven't tried either as yet. This is still a PLL, make no mistake, the motor/disk/photo-detector comprise the equivalent of a VCO, exactly the same as the more familiar 4046 arrangement.

Now with a 'missing pulse' input and a 'missing pulse' feedback there is a chance that it should achieve frame-lock also. This all hangs on the loop gain, damping and mechanical elements (as ever).

Steve A.

Hi Steve

Yes The Bistable idea is new to me as well and i have not tried the 4046 for motor control either .
So its going to be interesting see what happens ...i know i should really test as i build as its rare to switch something on and it works first go but we will see.

I have one other idea while also reading the back issues ...The 4528 monostable see pic ...you can get the frame pulse via this i could use this for my little drum ..not sure if i need a missing pulse on the opto fork if i use this idea...so looks like theres a few ways to do it ...it was used for a scope as i don't think any ones needed it for a second motor idea .

[Harry Dalek]

Just been working out the next circuit in a block diagram idea so looking at what i want it to do i think i can drop one 555 monostable since the 4528 will do the same thing really ...so this is what i think i will make.
On the 555 astable its just for testing perhaps i should have 2 of them free running and should show if i could sync them together, i just put one in for circuit testing ...i have lots of 555's doing nothing in a box.
I should of called the idea really monostable NBTV 2 drum control theres more of them than the one bistable or the Flip Flop.

[Harry Dalek]

My circuits about done really i have tested it apart from the NBTV sync
so seems to be no mistakes leds flashing away as they should.

I have changed my plans in the last post i have placed a schmitt trigger infront of the monostable for the opto fork its used for high speed switching .

So what you see in the picture is top left 555 schmitt trigger to monostable pulse width adjustment 555 then to the Bistable ,the switches are there for the set reset of the bistable as i am not sure if i should use the nbtv sync for the trigger or reset and visa versa for the opto fork so i can flip them and see what happens ...
The last ic at the top is the 4528 dual monostable one to do again the trigger or reset of the bistable and the second half to get the frame pulse to clock my small drum on the stepper motor circuit .

Next row down is the Steve version of the club motor control circuit using the Lm311 in the above post the switch after the PLL is to switch between the bistable control or the pll club circuit ...again no other reason but to see making two different control systems.

The bottom 555 is just a clock to test the board ic's are working it has a push on only switch for this so its would normally be off ...

Will it work ? we will see but a big thanks to Gary and steve for the interest and advice.