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No VDC tension mesured between + and -


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I bought a Shelly Plus 0-10V Dimmer which I want to use with a variable frequency drive (VFD) to control the rotation speed of an asynchronous motor.
The VFD accepts an input signal between 0 and 10 VDC which proportionally varies the motor's rotational speed.

In my installation, the Shelly is powered in accordance with the instructions with a 220VAC voltage on the L and N terminals. It is well paired and connected to my Wifi.
I access and control the Shelly without difficulty both via the http interface and Home Assistant.

Surprisingly when I activate the Shelly and use the variator at 20, 50, 75% no VDC voltage is measured with a multimeter between the + and - terminals
I would have expected to find a voltage between these 2 terminals, I measure tiny values, ex 0.25 VDC, but not the expected values Ex: 5 VDC with the dimmer set to 50% or 10VDC with 100%

Can you help me understand this phenomenon?
With the dimmer set to 50% I should be able to measure 5VDC between these terminals, right ?
Is it correct to think that the Shelly provides an output between 0 and 10 VDC between the +/- terminals like an adjustable VDC power supply?


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The Shelly plus 0-10V Dimmer has a passive 0-10V output. It delivers no voltage, but a pulse wide modulated impulse train. Most LED drivers use PWM 0-10V inputs which deliver the necessary voltage of 10 V DC. To get an active 0-10V PWM output, you may use an additional Shelly Add-On plus:



The 4,7kΩ resistor improves the linearity. It may be omitted if this tradeoff is negligible.

Edited by thgoebel
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