Help with Water Pump

[alec_t]

What does PWS stand for?

It's the Pulse Width Section (the section with U1a, U1b in it) to provide synchronous delays of the coil energisations. Each pump needs one PWS to provide respective SpeedCon and Prolong signals. One Speed Set Section can provide the Spd and Ref signals for several pumps. I now assume for your 'feed' speed one SSS will be used with 2 pumps. (I assumed originally that you might want up to 4 pumps to be set to the same speed at any given time). The aim of the SSS is to allow pre-setting a max speed and a min speed, then a simple 1-pole 2-way switch enables either speed to be selected subsequently.
The abbreviation 'PWS' is used only on that one schematic, which is why the search function failed to find it in the body of the text of this thread.

The motor grounds on the PDMs or "Power Gnd" should go right to the 20 volt supply

That would be best. The ground point of the 78L12 regulator is probably the best point to branch off the SignalGnd line.

 

[salty joe]

That would be best. The ground point of the 78L12 regulator is probably the best point to branch off the SignalGnd line.

I'll ground all signal grounds at the voltage regulator. Thanks for the tip.
Can I connect all signal grounds from both PDMs to a single terminal that goes to the voltage regulator?

Here is a link for capacitors that just arrived. They were sold as 0.39uf, 250V. 394K 250V is printed on the capacitors. I just read the desciption and it says 0.39mf. I planned to use these for C2 of the pulse width section. Does this look like the right part? **broken link removed**

I'm almost done with the first pair of PDMs except for the tantalum capacitor. (C3) It should arrive any day then I can make sure I've got the new PDMs right before making more copies. Many thanks.

 

[alec_t]

Can I connect all signal grounds from both PDMs to a single terminal that goes to the voltage regulator?

Yes (though I only envisaged one SignalGnd per PDM).

Does this look like the right part?

Yes.

 

[salty joe]

Yes (though I only envisaged one SignalGnd per PDM).

Yes.

I ended up putting the IC off in a corner, so it seemed like two Signalgrounds/PDM.
Great news about that cap. That's a relief-thanks.

 

[salty joe]

I want to start building the speed module while waiting for the tantalum capacitors to finish the first pair of PDM 15s. On the interconnections sheet the fast node from speed control goes to the tidal timer. But there is no fast node on the tidal timer.
I am unsure how to activate the speed control. Will I need pots or trimmers? I’d prefer trimmers if possible. Is it realistic to have a button to push that would activate the speed control (slowdown) for a set time?
Does TPASM from the interconnection sheet stand for Tidal something something Simulation Module?

 

[ronv]

I can't find a speed control schematic in the post. Maybe I missed it.

 

[KeepItSimpleStupid]

Tantalums: Hurry up and wait - OK
It has been suggested earlier to build all of the PDM's the same and there is no reason not to.

Trimmers or pots: Your choice. Whatever floats your boat. Trimmers make more sense in my mind.

Feed mode: Give alec a time range. It may have been already taken care of. Alec?

TPASM - I'm sure it stands for something. It's definately not a TLA (Three Letter Acronym). Alec?

 

[salty joe]

I can't find a speed control schematic in the post. Maybe I missed it.

Ron, Alec wrote the speed module and posted it as an attachment awhile ago. The search thread function does not work for me-otherwise I’d search around for you. I don’t think this forum likes my computer. Jeez, if I write more than a line or two, I go to Word and copy and paste because the lines in my reply box jump all over the place. I wonder if it’s because my computer is a 32 bit system….

Tantalums: Hurry up and wait - OK
It has been suggested earlier to build all of the PDM's the same and there is no reason not to.

Trimmers or pots: Your choice. Whatever floats your boat. Trimmers make more sense in my mind.

Feed mode: Give alec a time range. It may have been already taken care of. Alec?

KISS, I am building exact copies of all PDMs. But before I build all of them, I thought it might be a good idea to build one pair of PDMs then build the speed control, fault sensor and alarm systems and tie it all together for a test run.
Alec, if it’s doable, about 15-20 minutes of slow time for the filter pumps would be ideal at feeding time. It’s just that if I have to remember to turn the filter pumps back on high-I’m sure to remember. After I’m ten miles down the road, that is. Plus quite often I’ll need to feed the tank on the run.

 

[KeepItSimpleStupid]

KISS, I am building exact copies of all PDMs. But before I build all of them, I thought it might be a good idea to build one pair of PDMs then build the speed control, fault sensor and alarm systems and tie it all together for a test run.

Bingo - all on the same page. Alec, I believe, said the same. Speed control should be next on the agenda. One fully working PDM and test. Then build more.

I remember asking you if you had one of those stupid mechanical timers with the pull thingys, so you could exercise a pump like every half hour or whatever. Half hour ON, half hour OFF by pulling out every other tab. All you need is a relay with a 120 v coil and a plug and whatever would make it impossible for the 120 VAC to get near the contacts of the relay. Could be as simple as heat shrink tubing.

Today was an interesting day for me. I tackled an Oxygen sensor on the car. The hard part was figuring out how to open the connector. Fortunately there was a connector to the other O2 sensor with much easier access than between the engine and the firewall and there was the Internet with help.

 

[salty joe]

I can't find a speed control schematic in the post. Maybe I missed it.

Found it-post 905.

https://www.electro-tech-online.com/threads/help-with-water-pump.124250/

 

[alec_t]

On the interconnections sheet the fast node from speed control goes to the tidal timer. But there is no fast node on the tidal timer.

The 'Fast' node goes to TPASM (the Tidal-timer, Power, Alarm and Speed-set Module), as per:-
View attachment 69078

I am unsure how to activate the speed control. Will I need pots or trimmers?

The Speed-set part of TPASM is just a switch[*see below] to select either 0 or 12V, which then is used by the Speed Control module to select either of the pre-set speeds (max or 'feed') as set by the trimmers.

I thought it might be a good idea to build one pair of PDMs then build the speed control, fault sensor and alarm systems and tie it all together for a test run.

Good thinking.

Is it realistic to have a button to push that would activate the speed control (slowdown) for a set time?

No peace for the wicked . Seriously though, yes that's doable. The switch mentioned above could be the contacts of a mechanical timer as KISS stated, or we could design/build a module to do that. I don't have a clue about coral behaviour: would 'feed time' have to be tied to real time (e.g. can only happen at night, or at high tide)? Would the timer always be started by hand or do you envisage adding an automatic-feed system?

 

[KeepItSimpleStupid]

My mechanical timer was just an idea for accelerated testing. Basically a large number of on/off cycles per day. The mechanical timers have a lot of possible events.

Us could think about feeding in terms of the timer, BUT and their are always lots of buts. Suppose Joe bought a commercial feeder, but knowing Joe, he would want to make it himself. I would suspect a feeder could have it's own timer, so then there is the problem of interface requirements. Is there a contact closure? Do you monitor current? Read a light? Whatever.

@alec: I think I would go with a manual/auto feed mode switch of some sort with the famous "hook" to be able to interface with something else. Manual feed is just that, push a button to slow the pump for x-time. The "hook" could be an edge trigger. I think there is a CMOS chip where you can select the edge, whether it be rising or falling. Re-trigerable to extend the period?

 

[salty joe]

It would be real nice to push a button that slowed the pair of filter pumps for 15-20 minutes when I feed the tank. The wave and tide pumps would keep on rocking the water. Just to keep food from going into the filter. So yes always started by hand.

Thanks for that attachment-I'll get a chance to study it later tonight. It's off to my girl's basketball practice right now.

 

[alec_t]

Ok. Looks like an n-minute timer with push-button trigger + hook for alternative trigger. Thinking cap on. Watch this space.

 

[salty joe]

Ok. Looks like an n-minute timer with push-button trigger + hook for alternative trigger. Thinking cap on. Watch this space.

Thanks Alec-I appreciate the heck out of that.

I have the tidal controller and wave controller on the same board. This morning I ran a signal ground line from both 7812 voltage regulators to a terminal point. Is that OK or should each controller have a dedicated terminal point for signal ground?

The tantalum capacitors for the PDMs got here and are installed on the first pair of PDMs. I won’t get a chance to test until tomorrow-it’s off to swing a hammer right now and my son has a wrestling meet tonight.
Thanks all.

 

[alec_t]

I have the tidal controller and wave controller on the same board. This morning I ran a signal ground line from both 7812 voltage regulators to a terminal point. Is that OK or should each controller have a dedicated terminal point for signal ground?

I've mislaid my copy of the wave controller .asc file. Can you attach it please? As for the two 7812s, it's probably best to use just one so that there's no risk of their outputs getting cross-connected at any point.

Here's a suggested Feed-speed Timer Module (FSTM)
View attachment 69155
C4 and C5 are connected in parallel so as to use cap values you already have.

Edit: Scrub the request for the asc file.
Here's how I envisage the wave controller, with ins/outs labelled for consistency with the other modules :-
View attachment 69158

 

[salty joe]

The feed time module looks fantastic! Thank you! What does the optional trigger do? Would a doorbell button work for the button?

Here is the wave controller I have on the same board as the tidal controller.
**broken link removed**

It only operates two pumps.

 

[alec_t]

What does the optional trigger do?

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.

Would a doorbell button work for the button?

Sure.

Here is the wave controller I have

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.

 

[KeepItSimpleStupid]

@Alec

It looks like the feed "hook" is negative edge triggered which I guess is probably fine. Any reason to include programmable (rise, fall via jumper) edge detection there?

I could envision an I/O module connected to the output of an AC timer, and it's output would be open collector. If there was some DC powered gizmo then an Opto could be used, so probably the negative edge trigger makes sense.

Joe, for the sake of argument say you purchased this fish feeder: http://www.aquariumguys.com/current-aquachef-automatic-feeder.html

Note, it's really cheap, but would not have the required output. Let's just assume it has a motor to rotate the gizmo when it feeds or some solenoid release mechanism. So, you would have to find the voltage to the motor OR the voltage to the solenoid.

Armed with that information, one could add two components, a optoisolator (a 6 pin IC) and a resistor and trigger the pump feed mode. The timer would be the timer in the fish feeder. So, that's the plan.

You would essentially be building a version of this: https://www.electro-tech-online.com/custompdfs/2012/12/MR-BusIO-DCIN-Manual.pdf or even buy this, and change one resistor. I bought a few to play with. It expects 5V, not 12V for a logic supply. Gravitech has an AC voltage detection system too.

A alec said, you have to make a motor speed controller since one of your power supplies won;t go low enough in voltage.

 

[alec_t]

@KISS

It looks like the feed "hook" is negative edge triggered which I guess is probably fine. Any reason to include programmable (rise, fall via jumper) edge detection there?

Low level pulse will trigger. Don't think at this stage anything further is justified, but one base resistor and an npn would allow for a positive-going trigger if necessary.