How to connect 5V sensor to Industruino 4-20mA.ker
Hello,
I am interested in using the Industruino 4-20mA.ker transmitter. However, my sensor is 5-V sensor. I have some questions:
1) Is it possible to connect a 5-V sensor to this transmitter using a step-up converter ?
2) Is this transmitter require extra DC supply voltage from outside ? Or it can be powered completely from the 2-wire current loop (the 3.3V DC output from the transmitter is also generated from the 2-wire current loop) ?
Best regards and thank you very much,
The 4-20ma.ker (funny wording) delivers up to 15mA at its 3V3/GND pins to a sensor due to the datasheet https://industruino.com/shop/product/industruino-4-20ma-ker-89
A "simple" capacitor using "charge-pump" can typically (depending on chip and external components) pump a positive supply (V+) ...
- into a negative side, to provide an additional V-
- split a V+ into half (virtual ground)
- or add it on top to gain less than the double V+
Vout = 2* V+ - 2* Vf (of the additional diodes needed)
There are ICL7660 and others, typically operating below 10 (12) Volt, build for 10..20mA max., specified for V+ = 3V
providing about 2* 3.3V - 2* 0.6V = 5.4V 7.4mA max! (Iout / 2 - Isupply)
Due to the high output source impedance the generated voltage will strongly depend on the current drawn.
Limiting output to some 5V a zener diode may suffice (the current limiting resistor is already the output)? Using schottkys may be inappropriate?
So it is all up to "your" kind of 5V-sensor if it can live and survive with such a setup?
There is still the situation with the 3V3 side of the "current-maker" MCU - but that can be solved
Hi Irissar
1. No, only 3.3v, the inputs ADC and others inputs are on 3.3v.
2.The KER is a passive 4-20mA device, so needs a power supply to excite the output.
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| Asked: 6/18/24, 6:50 AM |
| Seen: 1283 times |
| Last updated: 8/24/24, 3:38 PM |