What is the typical voltage of the control signal?
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I have a question for everyone. What is the voltage of the 4-20ma current generated by the AO card? I measured the positioner of the control valve on site, and it showed just over 7 volts (with a safety barrier in between); the current signal was being transmitted. The valves on-site can operate properly. Is it enough as long as current flows? Is 7V sufficient as the operating voltage for the locator?
By the way, it says ±10V, 4-20ma on the AO card
First, understand 2-wire and 4-wire systems~
The voltage of the AO card is floating and can change; it can essentially function as a constant current source, meaning that the current remains constant while the voltage varies. Generally speaking, for positioners, the lower the current, the lower the voltage. In extreme cases, some positioners will not recognize voltage values below 4 mA. Therefore, it is necessary to carefully check the DCS settings for the DC output from the AO cards, to ensure that the system engineer does not set a current value that is too low
Thank you very much. I have another question: isn’t there any requirement regarding the operating voltage of the locator? Isn’t it usually 24V? The current in AO was previously a constant current; to maintain this current, the voltage would change. So how is the operating voltage of the positioner ensured? Thank you
The control panel of the valve is of the current-driven type; what’s the point of worrying about the voltage of the bulb? Just stand in the men’s restroom, focus on urinating, and that’s it – don’t waste your thoughts on the toilets in the women’s restroom. Confused thoughts, obsession, poor mental health. .
Thank you; the metaphor is vivid and extremely helpful! !
The voltage of the control valve is already low; as long as the current is normal, that’s fine
What is the relationship between the voltage after passing through the safety barrier and the card? 7V is enough; it’s usually around 7 or 8V.
That’s the European standard, right? The voltage is converted from 24V to 8V
I guess you’re measuring the voltage while carrying a load: lol