For integrated temperature transmitters and ultrasonic level gauges that only require on-site digital displays, how is the power supply addressed?
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There is a project that requires instruments to have only on-site digital displays; examples include integrated temperature transmitters (for explosion-proof areas, integrated units are chosen to avoid the need for positive-pressure enclosures), ultrasonic level gauges, and similar instruments. I would like to ask everyone how to address the power supply for these instruments? Is it necessary to have an instrument power supply box? Can I use a two-core wire for wiring, connecting it directly to the 24VDC terminal and the GND terminal?
1. A power supply box can be added to provide power directly. 2. Some instruments now come with dry batteries for internal power supply, which is very convenient; the batteries need to be replaced once a year
When choosing a meter with a battery, are there any differences in the models? Could you provide a few manufacturers?
If temperature sensing is only for use on-site, can’t a bimetallic thermometer be used instead? The price is low again
I’m not sure what the manufacturer is thinking; I’d like to request a digital display. I also think it’s a waste, there are even local explosion-proof areas!
One more thing to add: Of course, in some cases it is due to the current circumstances – the testing area and the operation area are not on the same floor!
There are flow meters with batteries, but it seems there aren’t any with temperature sensors； Simply use bimetal
:(It seems I’ll have to think about using solar or wind energy..........
You can come to me; I’ll help you solve a problem. QQ: 107433171
The field transmitter can be powered via a safety barrier. Theoretically, it is possible to power it directly with a 24V power supply; of course, in that case the transmitter must meet explosion-proof requirements. But this is equivalent to setting the output load of the transmitter to almost zero; it’s not clear what the consequences of that will be. If a 250-ohm resistor is connected in series directly between the transmitter’s negative terminal and the power supply’s negative terminal, there should be no problems.
Ultrasonic flowmeters are different; since all existing ultrasonic flowmeters are 4-wire instruments, the power supply circuit and the signal circuit are physically separated from each other. Therefore, it is sufficient to connect a 250-ohm resistor in series inside the wiring box of the ultrasonic flow meter.