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Pinout of SPWM-075-HD

Posted: Fri Mar 08, 2019 10:27 am
by bandtank
I have not been able to locate a pinout of the SPWM-075-HD meter in the datasheet, FAQ, or anywhere on this site. The electrical properties of each wire, even if they aren't used, should be available somewhere. Timing diagrams with setting times, maximum pulse rates, etc. would be helpful as well. I know the installation guide says to ignore the white wire, but I would like to see a connectivity diagram with the logical states/conditions of the meter connection.

It's not clear how the switches internal are wired and if there's a second switch that can be used to determine half rotations versus full rotations. There is also a double triggering issue due to bounce that could potentially be remediated with a second switch/trigger mechanism. I will post about that in another thread, though.

Re: Pinout of SPWM-075-HD

Posted: Mon Mar 11, 2019 3:09 am
by Jameson
Hello bandtank, and welcome to the forum!

The SPWM-075-HD does contain 2 separate pulse outputs. The black wire is the common. The red wire goes to pulse output 1 and the white wire goes to pulse output 2.

Im not sure what you mean by the electrical properties of each wire. There is no electricity coming from the water meter, our Omnimeter Pulse v.4 just senses when the reed switch in the water meter closes. The Omnimeter Pulse v.4 registers this as one pulse.

If you are using your own pulse sensing device, we recommend no higher than 24 volts on the pulse circuit and no more than 20 mA. The max pulse rate that the water meter will produce has to do with the maximum flow rate.

The Max Flow Rate of the SPWM-075-HD is 176 cubic feet per hour. It produces a pulse every 0.01 cubic feet. At the max flow rate this is 17,660 pulses per hour. This comes to a maximum pulse rate of 4.9 pulses per second.

Here is the spec sheet for the SPWM-075-HD: ... -sheet.pdf

I hope this helps.