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4-20ma to 1-5v converter

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dareenough

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Hi,
I have to convert 4 - 20mA from sensor(pressure sensor/temp sensor) to 1 to 5v using a resistor.
Extract value using ADC and save data in modbus registers. Request someone to please help me with the best schematic and the controller which goes well with this.Thanks in advance.
 
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mister_rf

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To convert the 4-20mA you need to use a 250 ohms resistor.
 

dareenough

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To convert the 4-20mA you need to use a 250 ohms resistor.
my final requirement is to save data on Modbus registers.Can some one pls guide me which controller and ADC can I use for this purpose
 

mister_rf

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Try to use "Modbus RTU Slave" with the Arduino UNO, see here:
http://arduino.cc/en/uploads/Main/arduino-uno-schematic.pdf
Arduino - Hardware
It has 5 analog inputs, capable of sampling 5 analog values and storing them storing them in 5 sequential registers. The Modbus master device can then query Arduino slave, and retrieve these values from the registers.
The Arduino only has full duplex serial lines, so you need an additional MAX485 IC chip to convert them into the half-duplex differential lines for RS-485.
Additional details here:
arduino modbus slave - jpmzometa
Modbus protocol, specifications and in depth tutorial
 

yulijun8866

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Hi,
I have to convert 4 - 20mA from sensor(pressure sensor/temp sensor) to 1 to 5v using a resistor.
Extract value using ADC and save data in modbus registers. Request someone to please help me with the best schematic and the controller which goes well with this.Thanks in advance.
4 ~ 20mA into 1 ~ 5V, ground and the sensor is in the negative power supply between the string of a 250 ohm, between power supply to the negative voltage and the sensor output is 1 ~ 5V. Similarly, 2 ~ 10V is a string of 500 Euro. But remember: because of the pressure transmitter between two points is the minimum voltage 9V, output if the string resistance to 5V, the best recommended supply voltage 15V, if the output to 10V, the supply voltage to the 24 best volts.
 
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