I’m about to launch into home automation with a view to improving self consumption of solar PV generation. I’d like to use some “industrial” devices that require a 4-20mA analog control signal.
Is anyone aware of a Z-wave device that has this output?
I can go some way with the 0-10V output from a Qubino Flush Dimmer as some the inputs of some devices can be configured to either voltage or current. This is however not true for all and having 4-20mA gives access to a much wider range of devices.
The signal converters I’ve found that can convert 0-10V to 4-20mA were all designed for industrial use and therefore too expensive. Besides, adding another device in the chain would not be very elegant.
I intend using a Vera Edge controller. If there is a cost effective way to get a 4-20mA output from it through some means other than a Z-wave device I would also be interested in that.
I hear ya. I’m an electrical/electronic commissioning supervisor on oil drilling rigs.
To be honest we are used to using 4-20ma stuff as it’s a safe standards for low energy spark proofing.
It’s expensive and simply not needed in non explosive environments.
0-10v tends to be the standard otherwise.
There are Fibaro modules that deal with Zwave to 0-10v in and out.
There are a range of components designed to work with a Pi or Arduino that work with 0-10v.
As you have found, the 4 - 20 ma interface is for long and noisy analog control in an industrial environment. Not much use in home automation.
If you want to work with 4 - 20 ma signals; my suggestion to create a 4 - 20 ma output from Vera would be to use the Fibaro RGBW. This unit will output 4 independent PWM signals (@244 Hz). I think this is fast enough to be able to be R-C filtered to create an adequate 0 to analog signal. From there you should be able to find a 4 - 20 ma converter.
This unit has 4 analog inputs as well. A simple resistor from an external 4 - 20 ma source can be sensed and read by Vera.
I’ll ask my instrumentation buddy at work to “translate” your post for me - I’m a chemical engineer with somewhat limited understanding of these things
My two intended applications are a VFD on my pool pump and a proportional solid state relay to vary the duty on my water heater element.
The VFD can be configured for either 0-10V or 4-20mA input. The SSRs are available in either 0-10V or 4-20mA input models, but I can source the 4-20mA model for about $60 less than the 0-10V model.
I’ve got two water heaters to control, so was hoping to save the $120 by finding a simple way from Z-wave to 4-20mA.
Vera and home automation in general do not have much analog capability. There are a few folks who chose to “roll their own” sensors etc but the majority of folks stay in the digital world.
Things you might consider:
[ul][li]Depending on where your pool pump is (mine was in my back yard some distance from the house). Getting a reliable Z Wave signal to the pool might be an issue. That leaves keeping the Z wave module in the house and running the control signal to the pump. For this, the 4 - 20 ma signal excels. But you will find the conversion from Z Wave (perhaps PWM) to 4 - 20 ma a challenge.[/li][/ul]
[ul][li]Before embarking on a direction with the pool pump, find how it handles transient commands. If the Vera control drops out and comes back quickly etc will it damage the pool pump?[/li][/ul]
Another though you might consider, Is it possible to limit the control authority of the Vera by pre-selecting 2 or 3 fixed settings. You can come very close to 4 - 20 ma control with a 24Vdc power supply (small wall wart) a few resistors and the Quibino RGBW.
Your instrumentation colleague should be able to help else I can be more specific if you wish.
This can easily be driven by 0-10V input Qubino 0-10V dimmer or alternatively as suggested Fibaro RGBW module. Alternatively (hi-tech), it can be controlled by rs-485 (mod-bus), rs-485 wifi interface, with some fancy code running on the VERA and talking to a RS-485 interface, but this is overkill in your specific situation, as simple control of the motor RPM is more than adequate.
Regards
Tiaan
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