This is basic... But you presented it intelligently... I never thought that... i only need a potentiometer to produce a current source... 😄 Thanks so much sir... Bravo.... Now i can test my positioner...with this simple cicuit device 😄 😄 😄
This video does a disservice to viewers who are hoping to learn more about making 4-20mA current loops work. It supposes that all one needs to make a 4-20mA current 'source' is a variable resistor. Well, in fact one can use a variable resistor by itself, as shown in the video, but it will never be a reliable 4-20mA controller. This is because it cannot monitor the actual resulting loop current, and cannot automatically adjust to variables in the current loop. If the power supply voltage wavers, the current will change. If the loop resistance changes (for any reason, including temperature, connection resistance, etc) the current will change. If another receiver is added to the loop, the current changes. The upshot of this is that a simple variable resistor can be used to vary loop current on a crude, temporary basis. But it cannot work effectively in real applications. Only a proper 4-20mA "transmitter" can do this, because a transmitter not only adjusts its own resistance automatically, it also monitors the loop current so it can compensate for resistance changes elsewhere in the loop.
Yes, dear friend you are right. It is a very basic form of current source through which you can test any instruments operational working, which needs 4-20mA signal at its input terminals.
IF YOU TURN THE POT TO LOW RESISTANCE POINT, IT WILL BE LIKE SHORTING THE 24V, HIGH CURRENT CAN DAMAGE THE MULTIMETER OR THE FUSE WILL BLOW, EITHER INSIDE METER OR THE POWER SORCE
Correct! though most trimming pots have limits set so they don't venture to that minimum resistance if so it will be open cirucit and show a fault on the control loop either on your DCS or control panel. Usually it will indicate fault that the valve has overtravelled or something along those lines
Thank u soo much sir Actuelly we have a lot of ultrasonic sensors in our water treatment plants and with some other equipments as well Thats y i requested for it Plz make more videos to do more simplify this importent topic
Very good video, just 1 question, why the R variable (potentiometer) have 3 wires? Resistance wire "A" go to + 24 vcd Resistance wire "B" go to multimeter (+) Resistance wire "C" go to ????? Thanks
Potentiometer say 5k ohm has three wires, A B and C. So, resistance between A and C will always remain 5k ohm. When we rotate the knob of potentiometer, resistance between A and B will increase and at the same time resistance between B and C will decrease. B is called as wiper terminal of potentiometer.
Atahualpa Gaytán the main reason is that it works as a voltage divider. it's like two resistance in one. if you connect only one leg it's like you have only one resistance. the difference is that using a voltage divider gives you more stable output that just one resistance.
That's wrong,This isnt a current source. a current source must give a constant current. That cun be using bipolar or FET by making Vb constant then Ic constant or Vgs constants then Id constant.
For precise variation in current, you need precise variation in resistance as 24vdc is constant. You can use ten turns potentiometer for precise variation in resistance.
This is wrong. It can not be used to test any instrument. Bacause instrument resistance will be added in series. Ideal current source keep current constant regardless of load resistance.
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This is basic... But you presented it intelligently... I never thought that... i only need a potentiometer to produce a current source... 😄 Thanks so much sir... Bravo.... Now i can test my positioner...with this simple cicuit device 😄 😄 😄
This video does a disservice to viewers who are hoping to learn more about making 4-20mA current loops work. It supposes that all one needs to make a 4-20mA current 'source' is a variable resistor. Well, in fact one can use a variable resistor by itself, as shown in the video, but it will never be a reliable 4-20mA controller. This is because it cannot monitor the actual resulting loop current, and cannot automatically adjust to variables in the current loop. If the power supply voltage wavers, the current will change. If the loop resistance changes (for any reason, including temperature, connection resistance, etc) the current will change. If another receiver is added to the loop, the current changes.
The upshot of this is that a simple variable resistor can be used to vary loop current on a crude, temporary basis. But it cannot work effectively in real applications. Only a proper 4-20mA "transmitter" can do this, because a transmitter not only adjusts its own resistance automatically, it also monitors the loop current so it can compensate for resistance changes elsewhere in the loop.
Yes, dear friend you are right.
It is a very basic form of current source through which you can test any instruments operational working, which needs 4-20mA signal at its input terminals.
How many watts? Please advice.
@@mobmt6239 How many Watts what? If you even need to ask about Watts for a 4-20mA application, then you probably don't understand the theory.
IF YOU TURN THE POT TO LOW RESISTANCE POINT, IT WILL BE LIKE SHORTING THE 24V, HIGH CURRENT CAN DAMAGE THE MULTIMETER OR THE FUSE WILL BLOW, EITHER INSIDE METER OR THE POWER SORCE
Correct! though most trimming pots have limits set so they don't venture to that minimum resistance if so it will be open cirucit and show a fault on the control loop either on your DCS or control panel. Usually it will indicate fault that the valve has overtravelled or something along those lines
Thank u soo much sir
Actuelly we have a lot of ultrasonic sensors in our water treatment plants and with some other equipments as well
Thats y i requested for it
Plz make more videos to do more simplify this importent topic
Arslan Ahmad
Very good job sir jee. Please make a lot of in this type vidio. God bless you
+Upendra Rao Thank you.
VERY GOOD, WELL DONE
What was the current rating for the vdc 24 volt which you used...let us know
Very good video, just 1 question, why the R variable (potentiometer) have 3 wires?
Resistance wire "A" go to + 24 vcd
Resistance wire "B" go to multimeter (+)
Resistance wire "C" go to ?????
Thanks
Potentiometer say 5k ohm has three wires, A B and C.
So, resistance between A and C will always remain 5k ohm. When we rotate the knob of potentiometer, resistance between A and B will increase and at the same time resistance between B and C will decrease. B is called as wiper terminal of potentiometer.
@@starautomation SO THE TERMINAL "C" we can leave without wire, wright?
Atahualpa Gaytán the main reason is that it works as a voltage divider. it's like two resistance in one. if you connect only one leg it's like you have only one resistance. the difference is that using a voltage divider gives you more stable output that just one resistance.
What if we know current output somewhere 400-1000 ma , varying voltage 25 -400
very nice video . thank you . need alot from you .
+Ayman Elsayed Thanks for appreciation
Good info...thanks
This is for generating current source from external DC power supply. How to simulate 4-20 mA current in loop powered instrument system??
You may have mentioned this in the vid but, my hearing is not that good. Is the pot 10 turn? Is it carbon or wire wound. Thanks.
It is wire would ten turns potentiometer.
Sir i am connect but may be I am wrong plz clear me connection of pot meter it have three terminal one common which two wire need to connect
Regards
🎉super
Thank you so much
Thank you Was useful
☺️
input 24v out v?
This is very dangerous to any instrument, you need to put one resistor in series first to limit the current not go up more then 20 mA,
If potentiometer is at zero resistance then, load will receive direct + 24V, and it will damage the load
potentiometer 3 k, voltage 5 vdc
So how much mili ampere??
wait for your new videos . thank you
I have a doubt .. you are checking current from positive and negative terminal. How it is possible
By checking with meter probes circuit gets closeed in series
Can we use directly as a m.a for vfd ? Or use R to I converter in between ? Please replay me
Yes. It is mA and can be used at analog input of vfd
Здравствуйте,R(resistor)=12000 Om? или 5 кОм?
Nice, it will be better if there is display.
That's wrong,This isnt a current source.
a current source must give a constant current.
That cun be using bipolar or FET by making Vb constant then Ic constant or Vgs constants then Id constant.
Thanks
I TRY IT BUT ITS NOT WORK.....
Not work
Nice video but I need more precise current.
For precise variation in current, you need precise variation in resistance as 24vdc is constant. You can use ten turns potentiometer for precise variation in resistance.
Oh brother, are you serious.
This is wrong. It can not be used to test any instrument. Bacause instrument resistance will be added in series. Ideal current source keep current constant regardless of load resistance.
wiasou sei denn de videos oooolbm ve sette kommischn inder de koan enlisch dorredn gmocht. bleibs in enkrn versifftn lond. ess pailts es jo decht net gorasou
sso
This is not a source children stuff
You have connected wrong
It is all tested. What you want to say, please clarify
Current source
Not correct method. This is jugadu method
Very bad idea, think again
Many thanks, was useful
Thanks you so much
Happy to help
thanks
Welcome