Could you provide a link to the Datasheet for the sensor. I want to see what type of output it provides. If it’s just a high/low signal once per rotation then that could be accomplished using our Enterprise Push Notification board, but if it outputs a PWM signal that would require a different product. I presume it’s just a high/low once per rotation but would like to know for sure. Relay outputs at the 9 remote locations should be no problem.
Any idea of the frequency of contacts coming out of the sensor?
Hello. Here is the information. But yes high/low signal 33 pulses per liter.
I think maximum is 275 pulses per second.
The idea is have both relay and pulse reader in same station.
Flow rate : 100-30000（m3/h）
Flow Pulse: F(Hz)=(0.55xQ) ± 3% Q=L/min
1 L water ~=33 Pulse
Max. Working Current : 15mA (DC5 V)
Min. Working Voltage: DC 4.5V
Working Voltage:DC 5V~18V
Load Capacity: =10 mA (DC 5 V)
Insulation Resistance: > 100M OHM
Accuracy :+/- 5% at (50~500L/min)
Cable Conection: Red: Positive+ (IN);Black: Negative- (GND);Yellow: NPN Pulse signal (OUT)
I’ve used these cheap flow meters and determined it’s better to track the flow verses flow rate, since each pulse is triggered by a given quantity of water. The local MCU would essentially measure a Totalized Flow, then it (or your Gateway) would calculate Flow-rates over any chosen time period.
You can get fairly accurate results if you calibrate the water-per-pulse at the operating pressure that the meter will experience. That can be as simple as a bucket test. They also work at 3.3V.
Do you have Power available at all locations? If not, is Solar Recharge an option?
@Travis, It looks like I use INPUT_PULLDOWN with a RISING Interrupt for most of these meters, but some require the opposite. But I haven’t seen a PWM flow meter in these cheap Chinese sensors.
I’m thinking (9) Photon Relay Boards w/ XBee’s, with (1) PR52-11 Gateway (or similar)?
To be honest @rfontaine has much more experience with these devices than I and I trust his opinion. What he is suggesting sounds correct to me. That would give you a relay as well has GPIOs for monitoring the sensor. That said what he is suggesting is a Photon relay board which will require a bit of programming. Do you have any experience with C/C++ application development? If so I would absolutely go with what Ryan suggested. If not let me know and we can discuss possible alternatives.
At this time we do not offer solar power accessories but it is certainly something we are looking into. Once again Ryan will have some fantastic recommendations for this as he has implemented it himself. Keep in mind @rfontaine is not an NCD employee but rather one of our most valued customers. He is a great guy and always willing to help out other users. Just saying that so you don’t hold him to Employee support standards.
Thanks Travis. The more I think about it, this will actually get quite complicated using Photons.
It may be easier to read the Flow Meter Output directly with an XBee (I/O sampling change detect) and aggregate the readings from all 9 XBees at an internet connected gateway (Cellular or WiFi).
Then have each XBee drive it’s relay (change a Pin High/Low) using an API command from the Gateway.
All 9 Flow Meter Xbee’s would be configured the same in XCTU, and you only maintain/modify your logic on the one Photon/Electron/Boron Gateway.
@Travis, do you have a relay board w/ XBee socket? I believe that was/is a major part of NCD, I’m not sure?
@dserrano, what Load will the Relay Drive, and @ what Voltage?
Your power budget (battery+Solar) will need to account for the Flow Meter, XBee, Relay Load, etc.
I’ll let @rfontaine comment on your solar power power components but they seem perfectly reasonable to me.
As for Ryan’s questions for the relay/input board controllable/monitor-able over XBee yes we have solutions for that like this:
That board has inputs for monitoring 0-5VDC or dry contact closure signals and a relay output. It can be ordered with different wireless XBee modules. One caveat though is you have to send a command to the board to read the input meaning it will not just send a transmission if the input opens or closes so you would need to poll the status of the input so that would complicate things a bit I believe.
If you could write the code to run on a PyCom Lora module and handle the wireless transmissions then I see that as a good alternative as well.