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 Post subject: Re: ECM-1240 counter questions
PostPosted: Fri Jul 16, 2010 12:03 pm 

Joined: Sat Jul 10, 2010 11:06 am
Posts: 38
paulb wrote:
I should have explained this..... The opto circuit is not related to the divider. I included the opto circuit because the one in an earlier post had not component values assigned.


Sorry, but I still don't understand.

If I want isolation to protect my softener electronics AND a divider to bring the frequency down to something the ECM can handle, do I need both of the circuits in your diagrams (Pulse Isolator and Pulse Divider), or does the Pulse Divider circuit itself also provide the necessary isolation?

And if it does require both circuits, how do I "combine" them? Which comes first (on the softener side)? What leads from one connect to the other?

Thanks,
Ira


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 Post subject: Re: ECM-1240 counter questions
PostPosted: Fri Jul 16, 2010 7:34 pm 

Joined: Fri Jun 04, 2010 11:11 am
Posts: 127
I will mod the divider circuit to incorporate the opto.


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 Post subject: Re: ECM-1240 counter questions
PostPosted: Fri Jul 16, 2010 9:36 pm 

Joined: Sat Jul 10, 2010 11:06 am
Posts: 38
paulb wrote:
I will mod the divider circuit to incorporate the opto.


Thanks Paul.

I went component shopping today and found everything but the flip-flop counter. The closest I could get to what you specified was a 74HC393, so I got one of those.

According to the datasheets I found, they are pin compatible, but it looks like there are some differences, most notably (I think) the input voltages. Can I use the 74HC393? If so, do I need to change any of the other components? Or should I order a 74LV393N on the 'net?

Thanks,
Ira


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 Post subject: Re: ECM-1240 counter questions
PostPosted: Sun Jul 25, 2010 12:25 am 

Joined: Sat Jul 10, 2010 11:06 am
Posts: 38
paulb wrote:
I will mod the divider circuit to incorporate the opto.


Paul,

Any progress on the new circuit diagram?

Thanks,
Ira


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 Post subject: Re: ECM-1240 counter questions
PostPosted: Sun Jul 25, 2010 11:14 am 

Joined: Fri Jun 04, 2010 11:11 am
Posts: 127
I totally forgot about the circuit diagram... I will post it momentarily.

The IC I specified is different in the supply voltage required to operate. It can operate with a supply voltage as low as 1V which is the "LV" (low voltage) designation of the part number. This requirement is because there is 1.6V readily available to power the IC, excluding the need for an external power supply. Your version requires a supply between 2V to 6V. You can make it work by using two AA cells in series to power it. The required consumption is very low and the battery should last a very long time.

The only modification would be to connect the battery negative to the GND line and connect IC pin 14 (and capacitor) to the battery positive instead of the COM terminal ... do not connect anything to the COM terminal at this point. If using the circuit described earlier, change the value of R2 to 4.7K.


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 Post subject: Re: ECM-1240 counter questions
PostPosted: Sun Jul 25, 2010 11:33 am 

Joined: Sat Jul 10, 2010 11:06 am
Posts: 38
Paul,

If it's not too late, post the "combination" circuit diagram using the original, low voltage IC. I'm sure I can order one online somewhere.

Thanks,
Ira


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 Post subject: Re: ECM-1240 counter questions
PostPosted: Sun Jul 25, 2010 11:52 am 

Joined: Fri Jun 04, 2010 11:11 am
Posts: 127
Here are the two isolated circuits, one with battery source which you can use with your current IC. The total circuit has not been tested but should work fine.


Attachments:
Pulse divider with isolator.png
Pulse divider with isolator.png [ 300.86 KiB | Viewed 3590 times ]
Pulse divider with isolator and battery.png
Pulse divider with isolator and battery.png [ 306.99 KiB | Viewed 3590 times ]
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 Post subject: Re: ECM-1240 counter questions
PostPosted: Sun Jul 25, 2010 7:03 pm 

Joined: Sat Jul 10, 2010 11:06 am
Posts: 38
Thanks Paul.

I'm going to put this together on a solderless breadboard to play around with it and test it without involving the softener electronics or the ECM-1240. So going by the diagram that includes the batteries as a power source...my plan is to hook up a 5Vdc power supply (actually puts out 5.2Vdc) to the two points shown as "From Pulse Source". I will alternate between contact and no contact on the positive side to simulate a pulse from the water meter. On the other end, I will connect my multimeter to measure the results. What should I see on the multimeter when I make contact with the positive side of the transformer? What should I see when I "disconnect"?

Also, regarding the actual physical implementation of all of this...

There are three buildings involved. The softener is in my well pump house. My LAN switch is in my shop which is about 25' away "by underground wiring". My home is about 200' away "by underground wiring". Obviously, I need to get the data back to my home via the LAN. I would rather locate the ECM for this project in my shop because it is closer to the LAN (I'm using the EtherPort connection method), and because I want to use the other channels to measure power usage in my shop. So would it be better to locate this device that goes in between the softener and the ECM close to the softener (in the well pump house) or close to the ECM (in the shop)? Or does it make any difference?

Thanks,
Ira


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 Post subject: Re: ECM-1240 counter questions
PostPosted: Mon Jul 26, 2010 8:58 am 

Joined: Fri Jun 04, 2010 11:11 am
Posts: 127
Ira wrote:
Thanks Paul.

I'm going to put this together on a solderless breadboard to play around with it and test it without involving the softener electronics or the ECM-1240. So going by the diagram that includes the batteries as a power source...my plan is to hook up a 5Vdc power supply (actually puts out 5.2Vdc) to the two points shown as "From Pulse Source". I will alternate between contact and no contact on the positive side to simulate a pulse from the water meter. On the other end, I will connect my multimeter to measure the results. What should I see on the multimeter when I make contact with the positive side of the transformer? What should I see when I "disconnect"?

Ira


I have attached a "test circuit". With your meter connected as shown in the diagram, it should display approx 5V or approx 0V, depending on the state (hi or low state). Suppose you are connected to pin3 (divide by two), it should take two on-off transitions of the switch to cause the multi-meter to show a change in state, then two more switch transistions to change states again. Similarly, monitoring the divide-by-four pin should require four switch transitions to cause a change in state.


Attachments:
Pulse divider with isolator test circuit.png
Pulse divider with isolator test circuit.png [ 281.45 KiB | Viewed 3581 times ]
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 Post subject: Re: ECM-1240 counter questions
PostPosted: Mon Jul 26, 2010 9:03 am 

Joined: Fri Jun 04, 2010 11:11 am
Posts: 127
Ira wrote:
There are three buildings involved. The softener is in my well pump house. My LAN switch is in my shop which is about 25' away "by underground wiring". My home is about 200' away "by underground wiring". Obviously, I need to get the data back to my home via the LAN. I would rather locate the ECM for this project in my shop because it is closer to the LAN (I'm using the EtherPort connection method), and because I want to use the other channels to measure power usage in my shop. So would it be better to locate this device that goes in between the softener and the ECM close to the softener (in the well pump house) or close to the ECM (in the shop)? Or does it make any difference?

Thanks,
Ira


It is important to keep the ECM-1240 near the panel being monitored. Your divider circuit should also be kept near the ECM-1240. The long leads shoud occur between the pulse source and the pulse input to the opto-coupler circuit to prevent any induced noise (interference) which could cause false pulses.


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