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[obrienj]

I am automating what can best be called a Neanderthal irrigation system.  The water source is a snow pack fed irrigation ditch with less than consistant water flow.

I have a design for everything I need to do to automate this manual system except for pump control.

I can start the pump with an X10 device but I need to detect that the pump output water pressure is too low to continue either at startup or during water usage for a zone.

Square D and others make such low pressure cutoff pump controllers but I can't find any that provide computer detectable feed back of shut-off so I can take actions based on that and other inputs.

Is there a water pressure X10 sensor that sends status or can be polled or is there an X10 based pump controller with low-pressure shutoff that sends status or can be polled?

Otherwise does anyone have any idea on how to do this?

Regards,
Jim

[Knightrider]

Jim, can the low pressure switch be connected to a (contact closure) powerflash unit?  Are you using AHP? (I assume that you are)

If so, the pressure switch connected to the powerflash can be set to trigger a macro which will shut the system down.  Better still, you can set the code of the powerflash as a monitored code and have that be a condition for the startup. 

You can even have a lamp module set to the same code as said powerflash and have an indicator light for the low pressure condition.

[steven r]

...Square D and others make such low pressure cutoff pump controllers...

Do the low pressure cutoff pump controllers you've looked at close or open any kind of circuit? If so, you might be able to interface that with a Powerflash Module.

Looks like Knightrider was a little faster typer with the same idea. (Beat me by 1 min and 10 sec) 

[Knightrider]

Looks like Knightrider was a little faster typer with the same idea. (Beat me by 1 min and 10 sec) 

Just goes to prove that great minds think alike!

[obrienj]

Most pump controllers that I've looked at simply cutoff power to the pump when the pressure drops below a specific level.  Actually I would like to use that facility outside of the X10 stuff to provide backup protection for the pump.  The irrigation controller I will be using also provides for "run-away" protection by sending "ALL OFF" if a zone runs more than its alloted time and that includes the pump.  Bear in mind that this system will run unattended much of the time.

So that said, if I could find/(build with help) a relay that detects power off on the output side of the pump controller (BTW, 220V) and sends a 6-18v DC pulse to the power flash then at least my program code and irrigation controller would know the pump has stopped and why based on the c ode sent.

Sound reasonable?

If so, how to I do it?

Regards,
Jim

[bitman]

Neanderthal.... 

So easy a caveman can do it.

[Knightrider]

no need to pulse the powerflash.  I doubt you even need power to the switch itself. 

[obrienj]

Knightrider,

Could you please elaborate?

How might I determine via X10 that a non-X10 device has powered off or is there an X10 device in this "circuit" that I'm not seeing?

In the simpliest case, some control function(program or device) will send an X10 signal that will cause a low voltage to turn on the pump controller but I see nothing that notifies that control function that the pump has powered off.

Please exxcuse my lack of electrical engineering and X10 knowledge, I spent much of my 45 years in the computer business as a programmer or programming manager.  I speak bits and bytes, not electrons. :-)

Regards,
Jim

[dave w]

[snip]
So that said, if I could find/(build with help) a relay that detects power off on the output side of the pump controller (BTW, 220V) and sends a 6-18v DC pulse to the power flash then at least my program code and irrigation controller would know the pump has stopped and why based on the c ode sent.


In the simpliest case, some control function(program or device) will send an X10 signal that will cause a low voltage to turn on the pump controller but I see nothing that notifies that control function that the pump has powered off.

Please exxcuse my lack of electrical engineering and X10 knowledge, I spent much of my 45 years in the computer business as a programmer or programming manager.  I speak bits and bytes, not electrons. :-)

Regards,
Jim

Not sure this completely answers your requirements but will give something to chew on. I used a similar set-up years ago on a 220V deep well pump.

For the input side of your control

Connect this 220V volt transformer to your pump motor supply line. The transformer is a 50Hz unit, but I doubt that 9 or 10 extra hertz will cause it to run hot since your load is minuscule. If it does you will have to find a 60Hz for North America usage.

http://www.allelectronics.com/make-a-store/item/DCTX-2292/BRIT.DC-ADAPT-9VDC-200MA/-/1.html

And connect transformer to this DPDT 9V DC relay.  Connect the appropriate relay contacts to an X10 Powerflash module. Since the relay will provide either Normally Open or Normally Closed contacts when the pump is supplied with power, you can wire the relay/Powerflash assembly to give you an X10, House Code Unit Code "ON" or a HCUC "OFF" when the pump runs.   This only detects that the pump has power, not that the pump actually runs.

http://www.allelectronics.com/make-a-store/item/RLY-523/9V-DPDT-MINI-RELAY/1.html

For the output side, connect a X10 Universal Module to your pump controller, the Universal Module will provide a closure when you send it a HCUC ON signal. Use the closure for the controller trigger.

Everything in between the input and the output is bit banging...right up your alley. You could use the CM15A controller and AHP software from X10 for your logic. You could use pressure sensors and more powerflash modules to provide high pressure/low pressure limit inputs to your logic.

Bare in mind X10 protocol is not the most reliable. I would plan to send redundant OFF signals to the pump controller,  and if damage could occur if the pump ran too long, create a fail safe backup to shut off pump.

[Knightrider]

I'm guessing (and only guessing) that the pressure switch is just that -- a switch.  Forget about the voltage.  Set the Powerflash to detect a contact closure and hook to the line and load sides of the switch.  Just make sure that you aren't sending any other current through it other than what's being supplied by the powerflash. 
Now, when the pressure switch triggers, a command can be translated to a HCUC.