Pulse Output for water meter

[ben]

Ben,

Much thanks and please do extend the same to Paul.

Teken . . .

Paul says "PNP, and NPN will work".

You'll need a separate power supply for the sensor itself.

Ben

[knarfm]

Vitaliy, could you please describe how you wired the AFP 989? What wires connect to the power supply and what wires connect to the GEM. The data sheet is confusing and shows only 2 wires. Is that a resister in the diagram too? If so what is the value?

[vitaliy_kh]

Hi,

Sensor itself has four wires interface.
Pulse counter input needs only two wires.
Here is a link to the sensor’s spec:
http://www.emxinc.com/pdf/photoelectric ... FP989S.pdf
Blue Wire is a Common GND.
This wire should be connected to the Pulse Input Common (GND) and to the Negative (GND)
of the Power Supply for the sensor. Power Supply for the sensor could be any type of DC
voltage source with output voltage from 10V up to 30V (12V DC Regulated Power Convertor
is preferable but not required.) Positive wire from Power Supply should be connected to the
Brown Wire of the sensor. (Brown Wire is a power supply for the sensor).
White Wire is a Sensor Output Polarity configuration option. For this application it does not
really matter what polarity is. So connect White Wire to the Common (GND).
Black Wire is a Sensor Output. This wire should be connected to the Pulse Counter input.
Depend on which sensor version you are using (NPN or PNP) and what exactly GEM input
is configured you may need external Pull-up or Pull-down resistor.
I am using ECM-1240 (not a GEM). Pulse input already has a Pull-up resistor.
So, in my case I don’t need external resistor at all. But only NPN Sensor version is directly
compatible with ECM-1240 Pulse Input.
If GEM Pulse Input has an Input OptoCoupler the wiring story will be a bit different but
actually more flexible.
I am not sure what resister you are referring to.

- Vitaliy

[knarfm]

Hi Vitaliy,
Thank you for clearing that up for me. What I thought was a resistor on the spec sheet wiring diagram is clear to me now as being the actual pulse counter.

[vitaliy_kh]

Hi,

Well,
- “yes” if GEM Pulse Counter Input is a low impedance logic
(i.e. opto-coupler or it already has a pull-up or pull down resistor);
- “no” if input is a high impedance (i.e. CMOS Gate, Comparator, etc.)

Depend on exact Input Implementation (this info may be highlighted
in GEM documentation or Ben or Paul should address this question in
a better details) you still may need external resistor.

For instance, ECM-1240 input is a Comparator with built-in pull-up
resistor. In this case NPN sensor is directly compatible with ECM-1240 input.
PNP Sensor still could be used but will require few external components.

Happy Holidays,

- Vitaliy

[ben]

I got Paul to look over the PDF file, he altered the diagram to show how to install it.

Pulse counter connection.png (49.91 KiB) Viewed 20816 times

[knarfm]

Thank you Vitaliy, Ben and Paul.

Vitaliy, for the sake of knowledge Here is the descriptions for the Pulse Counters on page 22 of the GEM manual:

The GEM has four pulse count inputs.

Pulse counter #1 and #2 are totally isolated from the GEM ground and circuit. Either of these two inputs require a DC pulse signal between 3V and 24VDC.

Pulse counters #3 and #4 are “dry” contact type counters. These inputs require switch contacts not connected to any power source, such as relay contacts or magnet switch contacts. Very low voltage from the circuit (5VDC) is used to complete the circuit.

I am not sure if I have permissions to post the diagram on that page so I will leave that up to Ben if he thinks that will help others as well.

[ben]

Thank you Vitaliy, Ben and Paul.

Vitaliy, for the sake of knowledge Here is the descriptions for the Pulse Counters on page 22 of the GEM manual:

The GEM has four pulse count inputs.

Pulse counter #1 and #2 are totally isolated from the GEM ground and circuit. Either of these two inputs require a DC pulse signal between 3V and 24VDC.

Pulse counters #3 and #4 are “dry” contact type counters. These inputs require switch contacts not connected to any power source, such as relay contacts or magnet switch contacts. Very low voltage from the circuit (5VDC) is used to complete the circuit.

I am not sure if I have permissions to post the diagram on that page so I will leave that up to Ben if he thinks that will help others as well.

You can post it if you'd like.

Ben

[pstanev]

Ben,

Is the wiring diagram from the post above good for the ECM-1240 pulse count input?

Regards,

[ben]

Can't just use it like that unfortunately, Paul is going to modify the diagram to reflect the ECM-1240.

Ben