Help with Water Pump

@alec

Agree. What do you envision is the minimum pulse width? Is it retriggerable? i.e. If it's doing it's cycle, will the push of the button extend the time?

@KISS
Sim shows 1uS trigger pulse is sufficient. It's deliberately non-retriggerable, so that a power-glitch won't extend the time.

@alec
Does it have to be a pulse, or will an edge do as long as the level has returned to a high before the next pulse?

alec_t said:

It's the 'hook' KISS advocated. Just in case you decided to use an automated feeder in the future. Your choice whether to connect that point to a terminal or forget about it.
Sure.
Ah, that version. Faint bells ringing. If you've actually built that circuit in full then the voltage regulator section to the left of C5 is unnecessary if you already have a 12V source from the tidal controller, and the part with the FETs should be modified to drive two PDM-Mk15. In other words the outputs of U1a,U1b provide the respective Vt drive signals for the two PDMs, which now supercede circuitry to the right of U1a,U1b.

Edit: Before building the Feed-speed Timer, the Speed Module needs to be built and shown to work with a pump. That will depend on the pump behaving similarly to the fan motors I tried.

Click to expand...

If I understand you, using two PDM-Mk15s I will only need five components for the wave controller to alternate equal on/off times for two pumps. (when 1 pump runs, the other pump rests), using the 12V section from the tidal controller for both tidal and wave controllers. From the wave schematic they would be the IC 40106, 0.1uf cap (C4), 100uf cap (C5), 22K (R1), and a 500K trimmer. Is that right?
Thanks for the heads up to build the speed module before the feed-speed timer. I have all the parts for the speed module. First I want to get the controllers squared away and I still need to test the new PDM-Mk15s. With luck I’ll get them tested tonight-If not tonight, Sunday for sure. Tomorrow is all day wrestling meet/tournament. It really is all day.

Wow, the ability to tie the slow pump feed mode with an automatic feeder would be very sweet. I will most definitely bring the trigger hook to a termination point. You can get some nice automatic feeder for $30 or so, which I think is a good deal.

Thanks guys.

here is a youtube video of that fish feeder I picked out of the hat. https://www.youtube.com/watch?v=YJHj1InkeFo The manual seems useless, the video seemed OK. I THINK it mentioned that you can set the number of times the drum rotates.

It uses a 3V power source (batteries) and a motor. So as long as you can get it apart, your good.

Well, you don't even have to get it apart if you don't want to. A cemented small magnet and a hall effect sensor would work too.

Or add it anyway and have Alec design a "failed to rotate in 24 hours" alarm for you. Just kidding.

@ Alec,

1) The D6/R10 connections look good. Vt is coming off the cathode of D6 and the other side of R10 is connected to IC pins 5 and 6, D7, D8 & D9 as shown.

2) R11/R12/D9 are installed and look correct.

3) The voltage across Rsense when the pump is stalled is 0.03V for both PDM 15s.

4) This time the alarm sounded about 5-10 seconds after the pump stalled. After that, the alarm sounds when the controller toggles with or without a pump. That's even with the 50 K trimmer set to max.

I am working with one of the fussy pumps. Sometimes it will run for 2 toggles, sometimes three toggles, usually just one toggle. Once the pump quits running, it won’t start back up unless I power everything down and start over.

Sorry it took awhile for my response. I could not access the site yesterday or this morning.

I don't know about you guys, but I'm missing the latest posts. No idea if it's my computer or the site.

@alec

Something to think about. Suppose that the pump is doing it's protection thingy. No motion for 1 sec, it will shut the drive off for 5 sec might this interact? Something like, shouldn't he minimum time the pump is told to be on, be say 10 seconds?

This is just an idea and I'm not sure it has any merit at all, but trying to sync with a moving target might be what's happening. Dunno.

I don't know about you guys, but I'm missing the latest posts. No idea if it's my computer or the site.

Click to expand...

It's the site crash. Everything from 8-12 Dec got lost on all threads and things still aren't right with various functions. Yesterday I couldn't upload any attachments. Today the smilies and special characters seem all over the place.
I've bolted together the missing text. Here it is:

Text 8-12 Dec

Joe:
No alarm when the pump won't start. I tried the 50K trimmer turned all the way to one end and the other, but 3 of the pumps still would not run. They did make a quiet humm sound.

Alec:
Oh, I thought we'd cracked it for all the pumps. Try with the trimmer set ~mid-way and another 4k7 resistor temporarily across R4 in the PDM. That will raise the pump current limit to ~5.4A at start-up.

Joe:
Yeah, I thought the pump startup was behind us too.
Before I install the 4.7K, the only difference as far as I can tell between the two pairs of PDM 15 is the pair that won't start all the pumps has tantalum caps (47u, 25V) at C3, and the pair of PDM15 that has regular barrel type caps (47u, 50V) at C3 will start all pumps.
Could this have anything to do with it?

KISS:
Strange. There are differences with a tantalum cap. Generally, they are a bit more leaky and have a lower effective series resistance. It would not hurt to try the other cap.

Alec:
Strange indeed. Well observed. I specified tants as I understood them to be more stable and generally less leaky. We live and learn. I'll run a sim with 'leaky' caps and see what it shows.
Edit: Sim merely shows that a leaky cap would just extend the trip time or, in extremis, prevent the trip acting. Pump start-up should not be affected.

KISS:
The reference on capacitor selection backs me up.
BTW, Tantalums should not be used in timing circuits.

Joe:
I put another 4.7K alongside the existing (R4) 4.7K but it didn't help. The problem pump I've been using only runs for the initial toggle. So I removed the extra 4.7K and switched the tantalum cap for a regular cap. No help there either. Could not help myself-just had to give it a try.
It finally occurred to me that the pair of PDMs that toggle the all pumps with no problem is a PDM 14 with mod (or the version just before PDM-Mk15) and a 4.7K resistor replacing a capacitor (C4 on PDM 14) to drop the starting A from 8A or so to 4.4A, IIRC. There are some differences besides the tantalum cap at C3. I have to believe one of the differences between these PDM versions makes the pumps fussy.
PDM14

mod

PDM-Mk15

Thanks guys.

()blivion:
Have to agree with KISS on the caps. A good NP0 ceramic is best for timing circuits. *LINK*

KISS:
Except ceramic caps don't exist in big values.

Alec:
Thanks for the heads-up on the caps, guys.
@Joe
“It finally occurred to me that the pair of PDMs that toggle the all pumps with no problem is a PDM 14 with mod (or the version just before PDM-Mk15) and a 4.7K resistor replacing a capacitor (C4 on PDM 14)”
I don't remember C4 being replaced, other than in Mk15. In the Mk14 mod R6, previously 4.7k, was replaced by 10k. C4 is still there in the mod, to raise the current limit temporarily to ~8A at start-up.
I'm losing the plot; can't remember now why we went from there to MK15 . I'll have to check back through the thread, but for now it looks as though the Mk14 modded may be preferable as the pumps clearly need a kick to get them going.

Joe:
I have two pairs of PDMs. The pair that gives me no problem is discussed in post 1276. The other pair is PDM-Mk15.
Post 1286 (did not get around to installing input caps) and post 1298 might be pertinent as well.
Thanks all you guys.

()blivion:
“Except ceramic caps don't exist in big values. True, and it could get quite impractical to parallel them to get to a large enough value for long RC delays.”
However, I was under the impression that we were using a (relatively) high speed RC osc fed into a counter IC, to lengthen out the timing? Or are we talking about a delay circuit that uses one very long singular RC decay?
I guess if we are talking about the former construct, we would/could just go with a simple crystal osc fed into the IC and have a more accurate clock, then we wouldn't be talking about RC osc circuits at all. With the latter circuit, one could just use a very large R and hope the cap leakage is low. At some point though a LONG single RC delay becomes unfeasible because there will be no existing parts that have high enough capacitance/resistance, with a low enough leakage to stop things from locking up. And if you do find workable parts, maintaining reasonable accuracy becomes impractical. The before mentioned IC comes in handy well before this point. That, or someone kindly show me a pure RC delay circuit of more than 1 Hour that is good to the second.
I'm sure I don't need to yammer on as this should all be fundamental. I have a LCD project to get back to also.

KISS:
ob(): I think it was like a 47 uf cap.

ronv:
The comment about them Humming sounds like something wrong with the current sense line.
Shouldn't be able to stall the pump without the alarm going off either.
Sounds like 1298 is the bug.

Alec:
“The problem pump I've been using only runs for the initial toggle.”
Is the power supply up and running before you switch on the tidal timer and/or pump?

Joe:
I have the power supply, controller and PDM wired together so when the power supply is plugged in, everything turns on. Sometimes a pump was plugged in from the getgo and sometimes I plugged a pump in after everything else was powered up. Either way, after the pump ran for the initial toggle if the pump was unplugged and plugged back in it still would not run. If everything was powered down and back up, then the pump would run for the initial toggle.
I have been using toggle times of 5-10 sec. on, 5-10 sec. off.

Alec:
“The pair that gives me no problem is discussed in post 1276”
Two versions are discussed there. Do you mean the second one (i.e. with C4 removed and a 4k7 connected across Q1 base-emitter)?
“If everything was powered down and back up, then the pump would run for the initial toggle. I have been using toggle times of 5-10 sec. on, 5-10 sec. Off.”
I'll sim that tomorrow and see if I can replicate the symptom.

Joe:
“Do you mean the second one (i.e. with C4 removed and a 4k7 connected across Q1 base-emitter)?”
Yes, C4 removed and a 4k7 at Q1. This pair of PDMs runs the pumps without problem.
And thank you.

Alec:
PDM-Mk15
1) The only way I can get the PDM-Mk15 sim to show 'runs for 1st toggle only' is if the Vt signal isn't getting to what is now D6 to re-initialise the trip via D6/R10. Check connections there.
2) Do you have R11/R12/D9 in place?
3) For the pump that doesn't run but hums, measure the voltage across Rsense, then switch off (pump may get warm if left in hum state too long).
4) If the pump hums/stalls but the alarm doesn't sound, check that 12V is getting to the R6/Q2emitter/Q3emitter node.

Joe:
Thanks Alec. I will get started in the morning.

Suppose that the pump is doing it's protection thingy. No motion for 1 sec, it will shut the drive off for 5 sec might this interact?

Click to expand...

Quite possibly. Joe, could you set the toggle times for ~20 sec and see if you still get things going on/off at 5 sec intervals? If they do then the internal protection thingy is the likely cause.

3) The voltage across Rsense when the pump is stalled is 0.03V for both PDM 15s.

Click to expand...

So the pump is drawing only ~ 150mA when stalled. So nothing should cook.

4) This time the alarm sounded about 5-10 seconds after the pump stalled. After that, the alarm sounds when the controller toggles with or without a pump.

Click to expand...

Odd. Perhaps with the toggle times set for ~20s we'll get a different result.

After you've repeated the test with a 20s toggle time, try temporarily disconnecting one end of D4 and see what happens. That should tell us whether the trip timer or the pump IC is holding the current at 150mA.

Thanks Alec, for retrieving that info amd putting it in ordrer. I'll run the 20 sec toggles and disco D4 tomorrow late morning.

50K trimmer set to max. 10-11 sec. is the longest off toggle time. I set the run toggle time to about 20 sec. and the pump toggled once or twice, sometimes three times. The alarm came on a few seconds after the first toggle, then the alarm sounded when the LED was lit-pump running or not. So, I could see no difference with pump behaviour with the longer toggle times.

With D4 disconnected, I could see no difference in pump or alarm behaviour.

Thanks.

I thought for a while the "The Christmas Decorating Monster" got you today.

Well, let's hope we can figure this out. I thought it was nailed.

@Alec
Do you have a photographic memory or something? Nice work. Thank you. I had a doc once that said if he saw a page of a text book, he could visualize the entire page word for word when he had exams. You don;t realize that people's minds can work very differently.

the pump toggled once or twice, sometimes three times. The alarm came on a few seconds after the first toggle, then the alarm sounded when the LED was lit-pump running or not.

Click to expand...

Hmm, I'll have to think about that.

With D4 disconnected, I could see no difference in pump or alarm behaviour.

Click to expand...

Unless there is any discrepancy between the Mk15 schematic and the circuit as built that suggests (a) the IC inside the pump does have a locked-rotor protection function which is kicking in or (b) the pump itself is not drawing the expected current for some reason. Does that particular pump behave perfectly with the OEM controller?

Do you have a photographic memory or something?

Click to expand...

In my college days, yes (I could visualise most of a page, but not quite word for word). Handy for exams, as your doc found. Alas nowadays it's like a sieve . I was able to retrieve the missing thread text by copy and paste from my browser history.

KeepItSimpleStupid said:

I thought for a while the "The Christmas Decorating Monster" got you today..

Click to expand...

It was the dreaded honeydo list.

alec_t said:

Unless there is any discrepancy between the Mk15 schematic and the circuit as built

Click to expand...

Today I will go over every component and every connection with a fine toothed comb. Can all resistor values be checked with a DMM while in a circuit? Can diodes also be checked while in circuit?

alec_t said:

Does that particular pump behave perfectly with the OEM controller?

Click to expand...

I never fired up the OEM controller because it needs 220V and a Euro style receptacle.
This particular pump, (pump A) is one of three (out of a total of six pumps) that behaves this way when hooked to Mk15. The other three pumps seemed to work fine, but I did not let them toggle long term.
All six pumps were fine with PDM14 both before and after I replaced a cap with a resistor to drop the starting amps.

@Joe:

Take the wall wart away. If you apply 24 VDC where the wall wart power goes into the OEM controller, (polarity doesn't matter), the OEM controller will work. The pump side of the OEM controller is polarity sensitive, so that has to be verified.

You can trace where to place alligator clips or even where to solder a couple of wires.

salty joe said:

Today I will go over every component and every connection with a fine toothed comb. Can all resistor values be checked with a DMM while in a circuit? Can diodes also be checked while in circuit?

Click to expand...

The short answer is no. The long answer is that the ohmmeter voltage turns on semiconductors in the circuit to various degrees introducing variable resistances. The Ohmmeter polarity can matter as well.
Now, checking for opens/shorts and answering (Is the connected) here - mostly yes. Capacitors also affect the circuit.

Thanks KISS, the OEM controller is fired up and running pump A through its cycle of low, medium, high and back to low with no problems. Too bad that cycle is almost no better than a non-controlloed pump.

I'll visually check each component and connection.

Alec,
Maybe you could repost the schematics. I think the links are missing now?

Yeah, and the links I can find don't work. I have the latest schematic for PDM Mk-15 stored in my documents. I just copied it and tried to paste it here, but could not so I sent a copy directly to you Ron.

I am not quite half done going over my PDM Mk15 and so far everything looks good.

Alec,
Maybe you could repost the schematics. I think the links are missing now?

Click to expand...

The site is still having problems with attachments; I've tried and failed to post a couple recently but will try again.

One difference between the Mk14 and Mk15 is the separation of PowerGnd and SignalGnd in Mk15. Joe, check that both are grounded. Also check that Rsense has good soldered connections (if either end has a high-resistance connection the pump won't start).

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