0-5 V to 4-20 mA linear conversion from voltage to current signal transmitter, this is the circuit I want to make.

Materials used in the circuit:

• XTR101
• BAT249
• BD243
• Level transmitter

I am setting up the circuit, I get 5 V at the output without connecting the level transmitter. When I connect the level transmitter, I can't get 5 V and I can't see 4-20 mA. What could it be for?

 

hi Mem,
Do you have a circuit diagram for the project you could post.?
E

 

ı dont have schematic, here is only such

 

hi M.
Without you posting a diagram, means I would have to draw the circuit diagram.

It would be quicker and easier if you drew the diagram, then I would do my best to help you.

E

 

The schematic is similar to this, my sensor has 3 legs, pdf

 

The schematic is similar to this, my sensor has 3 legs,

How's that going to work, the schematic shows a 4 wire bridge type sensor?
A 4 to 20 ma transmitter requires a load resistor normally at 250 ohms. This creates a 1 to 5 volt output depending on the current through the loop.
Is the board you have designed for a 3 wire or 4 wire sensor?

 

Here's the schematic from what I can figure. I suspect C4 is a zener diode and R is the series resistor not seen in the photo blocked by Q1. Not sure what those 2 components labeled T1 are they look like resistors.
I'm assuming the 3 wires red, black and white are from the sensor. The red and black show connected across the zener diode and the white connected to input 3 but nothing connected to input 4.
It would appear this board is designed for a 4 wire sensor very similar to your schematic in post #5.

 

Here's the schematic from what I can figure. I suspect C4 is a zener diode and R is the series resistor not seen in the photo blocked by Q1. Not sure what those 2 components labeled T1 are they look like resistors.
I'm assuming the 3 wires red, black and white are from the sensor. The red and black show connected across the zener diode and the white connected to input 3 but nothing connected to input 4.
It would appear this board is designed for a 4 wire sensor very similar to your schematic in post #5.
View attachment 285131

The sensor I use is 3 legged.

 

hi M,
You have to make the input a 4 wire. A full Bridge, your sensor is only a Half Bridge.
Add the two 1K 0.1% resistors to Pin 4.
Add the 250R across the output B1
Do you follow, OK.?
E

 

hi M,
You have to make the input a 4 wire. A full Bridge, your sensor is only a Half Bridge.
Add the two 1K 0.1% resistors to Pin 4.
Add the 250R across the output B1
Do you follow, OK.?
E
View attachment 285138

I'm trying what you say now

 

hi M,
You have to make the input a 4 wire. A full Bridge, your sensor is only a Half Bridge.
Add the two 1K 0.1% resistors to Pin 4.
Add the 250R across the output B1
Do you follow, OK.?
E
View attachment 285138

my sensor is legged 3 , black,red and signal yellow

 

hi,
Look at this image,
This is what you have to do, add the resistors in order to make the half bridge into a full bridge.
The XTR must have a differential signal from the sensor and the resistors in order to work correctly.
The low value 47R potentiometer is to give a zero output setting from the bridge.
E

 

hi,
Look at this image,
This is what you have to do, add the resistors in order to make the half bridge into a full bridge.
The XTR must have a differential signal from the sensor and the resistors in order to work correctly.
The low value 47R potentiometer is to give a zero output setting from the bridge.
E
View attachment 285141

ı will connect the signal leg of 47r potentiometre to IN- feed?

 

ı will connect the signal leg of 47r potentiometre to IN- feed?
[/ALINTI]
How should ı draw a 3-legged sensor with this xtr 101 IC?

 

hi.
The wiper of the Pot goes to pin #4 of the XTR
The White wire of the sensor to Pin #3
E
If the polarity of output voltage of the XTR is reversed, you will have to change over the Pin# 3 and pin# 4 connections.

 

hi.
The wiper of the Pot goes to pin #4 of the XTR
The White wire of the sensor to Pin #3
E
If the polarity of output voltage of the XTR is reversed, you will have to change over the Pin# 3 and pin# 4 connections.
There is a 78M05 regulator in the circuit, ı guess thats the problem, what should ı use instead?

View attachment 285145

 

hi,
I don't understand what you are asking and why.
What is the problem.???
E

 

hi,
I don't understand what you are asking and why.
What is the problem.???
E

Hello,
Whe I plug in my signal terminals, I cant get a signal. I think the problem of this is that it cannot feed the XTR101 due to the 78m05 regulator.
There is a 78M05 regulator in the circuit, ı guess thats the problem, what should ı use instead?

 

hi,
Draw and post a circuit showing where and how the 7805 is connected.
E

 

hi,
Draw and post a circuit showing where and how the 7805 is connected.
E

Hi,
I added, unfortunately the is no schematic of the circuit. Places i marked with black boxes