Help with Water Pump

[salty joe]

Edit:

Presumably you weren't running 12V from that failed Vreg to the two filter pump PDMs? They should be getting their 12V from the FPPMk4 instead. The two sources of 12V should not be interconnected or things could fry.

Out of pure ignorance, I did. I saw the 12V tag on the FPPMk4 and connected it to the 12V from our (now fried) controller. Probably the root of the flickering LED? Sorry about that. No wonder I was having such a hard time with the battery backup.

So the LM317 out-12V goes to the filter pumps PDM with the 12V source being the battery? Is that right?

I really do appreciate you hanging in there while the parts arrive and the new controller gets built. Thanks!

The only thing I can come up with to explain the pulsing is either a couple wires got melted insulation when the Vreg got hot or something went haywire in an IC. I had 12V connected to the PDM Vt as well as the PDM 12V.
The IC in the PDM has pin 12 soldered to signal ground. I'm hoping I did not fry that pair of PDMs.

 

[alec_t]

So the LM317 out-12V goes to the filter pumps PDM with the 12V source being the battery? Is that right?

Correct. Sorry for any confusion, I thought that was clear from the FPPMk4 schematic but obviously not. Mea culpa. I was assuming the filter stuff was entirely independent (as far as power/voltage supplies go) from the wave and tide stuff, as it's only the filter stuff which has backup.

The IC in the PDM has pin 12 soldered to signal ground

Ok (if that's the 'fault' pin).

 

[salty joe]

Yes, pin 12 is what I used for fault in the filter PDMs.

I tried to download the tide schematic from my documents, but some kind of file error occurred. I also tried to copy and paste with no luck. I sifted through the thread, but we lost a lot of links when the site crashed awhile ago. So, I emailed the schematic I’m working with to you, Alec.

Awhile ago you had me change a cap ,IIRC, to “stretch” the adjustment of the flick because the flick was too long. It helped, but the flick is still too long. As long as I’m building a new tidal timer, is there anything that will give us a shorter flick time? The ideal flick adjustment would be from nothing or almost nothing, to a little spin of the pump.

 

[alec_t]

Got the email thanks. Wow, that timer version is ancient. Here's the most recent one which I think represents what you built:

Awhile ago you had me change a cap ,IIRC, to “stretch” the adjustment of the flick because the flick was too long.

From memory the cap C10 value was increased from 330nF to 4.7uF because the flick was too short. Also R3 was introduced to 'stretch' the adjustment. Since then various changes were made to the PDM, which could have affected pump start-up rate and hence the flick. Try with C10 = 330nF (or thereabouts) again.

Edit:

I'm hoping I did not fry that pair of PDMs.

Let's hope so. But if the 4093 IC was getting 12V at its supply pin (pin 14) from the Vreg and got 13.8V from the battery on the Vt (or other) input it probably died

Edit: I've just noticed we've made it past post #2000!

 

[salty joe]

Thanks for the latest tidal schematic.
Will either a 1A 40V or a 3A 40V Schottky diode work for D11?

And you were the one who hit 2000. That's as it should be!

 

[alec_t]

A 1A one will be fine.

Edit: I've just run a simulation of the effects of connecting 13.8V to the output of a 7812 Vreg. It showed current is driven back through the reg, even when 21V is present at the reg input. Power dissipation in the reg rises from ~240mW when the 21V is present to ~850mW when it isn't. No wonder the reg felt hot and died

 

[salty joe]

Plus, something happened to make the timer signal get to the PDM even though no timer line was hooked up??? only 12V lines-that timer is toast. Parts are on the way.

Is there a way to test the filter PDMs without a 12V line? Because I won't have 12V until the parts arrive.

 

[alec_t]

You may get away with using a PP3 9V battery as a temporary source. If that's not enough then 2 AA cells could be added in series with the PP3 to give 12V. Or a spare well-regulated 12V DC wall-wart would do. A desktop computer power supply also has a 12V output.

 

[salty joe]

OK, thanks. I think I'll wait until I build the tidal controller with a Vreg and keep my fingers crossed.
And this time no mixing battery 12V with controller 12V!
Thanks much, we'll get this.

 

[salty joe]

I can't figure out how to hook up pin 10 or pin 11 in the 4020 in post 2004. I don't understand what CP or the symbol beside CP means. I assume R means reset or pin 11.
I tried to make sense out the fried tidal controller-it really is a bird nest.
Is R pin 11 and is connected to C7 and R1 and nothing else?
Does pin 10 get connected to R2 and U2a and nothing else?


I got all my parts except for the 0.33u cap for C10. I'm building the 12V supply and setting the ICs with their caps for now.

 

[KeepItSimpleStupid]

Joe:

You have to learn to look for a datasheet. e.g: https://www.futurlec.com/4000Series/CD4020.shtml

CP is an internal designation for Clock Pulse.

Ignore what's inside the box except it helps US understand what the chip does.

Your going to care about pin 10 (Clock or phase 1) and pin 11 (reset)

C7 and R1 perform a rudimentary power on reset. At power-on the cap can be assumed to be shorted for a short time. Hence, the midddle of the network connects to the reset pin or R. Just don't go looking INSIDE the IC for pin R.

Pin 10 comes from the oscillator made up of U2a.

 

[salty joe]

KISS, I did already look at the data sheets for all three ICs and made notes on my print.
Because I am unclear how to hook up pins 10 and 11 in the 4020, in my prior post I put how I think they should be hooked up.
The last thing I want to do is fry more stuff, so I'll wait until I understand how to hook up pins 10 and 11 on the 4020.
Thanks.

 

[alec_t]

Hi Joe.
I understand your confusion, as the LTspice symbol differs from the one in the datasheet.
Here's the schematic with the relevant pins numbered.

 

[salty joe]

Thanks Alec. It hooks up the way I thought, but we all know what happened the last time I hooked things up the way I thought they should go. Thanks KISS, I think you were saying the same thing but I was still unclear. Now I can go with confidence-thanks all.

The unused even numbered pins on 40106 need to be connected to signal ground, is that right?

I want to add a green LED (power indicator) as well as the alarm module to this board. Can I use the signal ground or should I bring in a power ground?

 

[alec_t]

The unused even numbered pins on 40106 need to be connected to signal ground, is that right?

Er, no. Those are the gate outputs, which should be left unconnected if not used. It's the unused odd number pins which need grounding.

this board

Which one?

Signal ground is right for the alarm module. BTW it's ok to use a single alarm module for all the pumps (tidal, wave and filter). Just take the 'Alarm' outputs of the respective filter pump PDMs to respective diode inputs of the alarm module (which can have as many inputs as you like).

 

[salty joe]

OK, thanks I'll ground the unused odd numbered pins. Ohhhh that would have been bad!

By "this board" I meant the one I'm working on (TTAM).

If an LED is connected to 20V, would I need to bring in power ground or could signal ground be used?

 

[alec_t]

Signal ground is fine. It's only the pumps themselves and the PDM FETs which pass significant current (Amps) and need PowerGnd. Everything else draws only mAs and can use SigGnd.

 

[salty joe]

That makes it easy-thanks.
I can't seem to stay sharp for more than a couple hours at a time when soldering so today I run upstairs every now and then and clean house. Leah will be happy the house is squared away and I'll have a really good start on the TTAM. So far so good, I think so anyway.

 

[alec_t]

I can't seem to stay sharp for more than a couple hours at a time

I can relate to that. Must be something to do with our fading youth .
Good luck with the build.

 

[salty joe]

To ground the TTAM, should signal ground from a PDM be used?
Other than the .33u cap I’m waiting on and hooking up the ground, TTAM is done.