Do the pulse counters detect pulse edges or levels?

[dbreiser]

As my first attempt at using a pulse counter, I had the idea that I'd use a really cheap flow sensor in my water softener drain line (low pressure, almost no chance of adverse impact on my plumbing, easy to reverse if necessary, etc.).

The $5 Hall effect valve from China, though, sends out 450 pulses per liter -- way too high for the GEM. I happened to find a counter/timer that seems to have all the features I need to essentially divide-by-450 (or any other factor, for that matter), including a settable output pulse width so I can give the GEM its desired 0.55 second pulse duration.

The problem is that the both the connection diagrams and online demo suggest that the counter's output is held high until triggered, at which point the output goes low for the duration of the output pulse width, then returning to whatever +V is (12V by default in this counter, but a voltage divider would be trivial to do)

Can the GEM count pulses normally-high, pulses to 0 pulse style?

Dave

[ben]

Dave,

Normally high shouldn't be an issue. Paul sent me this diagram to attach.

Normally high input signal.jpg (40.06 KiB) Viewed 1664 times

[dbreiser]

Great. Thanks for the information.

I have the flow sensor and have ordered a counter. Once I get done grading final exams in a couple weeks, I should have time to try hooking them up to the GEM.

Dave

[dbreiser]

If I'd known what I was looking at in:
download/file.php?id=1532
I'd have had my answer before posting. Furnace control is closer to alternating plateaus than pulses. That figure seems to be showing that the pulse counter is counting both the leading and trailing edges of the 'furnace-on' thermostat plateau.

Anyway, I now have three different source types connected to counter channels:

Output of an AutomationDirect Counter-timer-tachometer that pulses from +12V to 0V for a configurable duration whenever the counter reaches the target from a hall effect flow sensor in my water softener drain line. The hall sensor puts out a 30Hz signal for the highest flow rate I see in that line (1 gallon per minute, or so).

A 0 to +12V, ~10 second wide pulse whenever my condensate pump runs. I'm using the counter's power supply controlled by a relay at the pump to send the signal to the GEM. I could have used the relay to act as a dry contact, but I have plans for both of those.

And a dry contact signal generated by a DLJ water meter. That's in a vertical line just past the water company's meter. The DLJ meter is reading about 1.5% lower than the water company's meter (and looks like it may be drifting lower). But I'm pretty happy because DLJ is the only source that says their meter can run in an orientation other than horizontal with the dial up.

I'm hoping to get a second DLJ meter in my water heater feed line. Still cold water, so if their claim of any orientation is correct, I can put it up between my joists with the dial down. I already have the signal line for that one run to the GEM. I wonder if my wife has my birthday present picked out

[ben]

If the DLJ meter is reading consistently low, I'd suggest adding a multiplier to compensate for its accuracy. The multiplier would have to be added to whichever software you're using.

[dbreiser]

I just use the dashbox web reports.

I want to get a few more 1000's of gallons through the system before I decide whether I want to try to correct the pulse counts. It'll probably be fine without explicit correction in the logs, I'll just have to remember to check it for drift over time.

Dave