Current source, 4-20mA Signal Generator - Test / Review / Opis

CMS 12195 46

TL;DR

A cheap two-wire 4-20mA signal generator/load current transducer tester was tested for simulating sensors and calibrating analog inputs.
It runs from 15V to 30V, connects in series with the load, and provides an adjustable constant current output with a digital readout.
The unit cost about twenty three zlotys plus seven zlotys shipping, and the display shows two decimal places, though settings change in 0.05 steps.
Measurements with a Sanwa multimeter showed the current was very accurate, and the tester could hold 10mA stably while supply voltage was varied.
The backlight is extremely weak, and using a 470Ω resistor caused large errors at 20mA; without the resistor, correct low-voltage operation started at lower voltages than expected.

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#31 17724101 23 Jan 2019 17:58

LChucki LChucki

Level 31

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Post #31
17724101 23 Jan 2019 17:58

dabek3456 wrote:
That toy measurements are made with other toys?

Then do a better test, write and you will get a flash drive.
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#32 17724200 23 Jan 2019 18:29

CMS CMS

VIP Meritorious for electroda.pl

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Post #32
17724200 23 Jan 2019 18:29

Buddy Dabek, instead of criticizing someone who voluntarily conducts tests for you in his spare time, and then describes it, also in HIS FREE TIME, I suggest you write an article yourself, or at least read Article - How much time and work the Editors of Electrode spend for you.

I will add this photo:

I am still not going to comment on your statements.

Best regards.
CMS
#33 17724334 23 Jan 2019 19:08

vodiczka vodiczka

Level 43

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Post #33
17724334 23 Jan 2019 19:08

CMS wrote:
I will add this photo:

You answered sharply and principally, but my colleague Dabek deserved a sharp retort.
#34 17724423 23 Jan 2019 19:30

CMS CMS

VIP Meritorious for electroda.pl

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Post #34
17724423 23 Jan 2019 19:30

Maybe I rose a little, but as my regular reader you know perfectly well how much nonsensical * I have to read sometimes in the comments. And an administrator, moderator, or editor is also a human being and has limits of patience.

* even about a draft in the room and loose wires during the reference voltage test. I am surprised that then I managed to refrain from commenting ...
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#35 17724472 23 Jan 2019 19:43

kkknc kkknc

Level 43

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Post #35
17724472 23 Jan 2019 19:43

You didn't lift yourself up. You even softly said it. I wrote a few reviews myself, I know how long it takes. I also have another. Only time .......
#36 17724533 23 Jan 2019 19:57

vodiczka vodiczka

Level 43

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Post #36
17724533 23 Jan 2019 19:57

CMS wrote:
Maybe I rose a little
Nothing at all. I like your answer with "picture script" or as you called it "picture"
#37 17724845 23 Jan 2019 21:05

Janusz_kk Janusz_kk

Level 39

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Post #37
17724845 23 Jan 2019 21:05

Unfortunately, but what, like what, but haters, we do not need to write articles because I do not have time, but I try
at least not to deny everything, just give constructive comments sometimes, but I don't understand the hate "dabka",
it is basically an amateur form, so there are methods like that, and for amateur applications they are sufficient.
And when he is looking for the opinion of professionals, let him go to specialist forums and not bother him, there is no obligation to read,
you don't like it, it's forums from the court as old people say.
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#38 17725047 23 Jan 2019 21:56

Anonymous Anonymous

Anonymous

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Post #38
17725047 23 Jan 2019 21:56

How do you know if I have more posts on another account? A weak argument. I wrote this post because I can see that the author is terribly resistant to the suggestions of others, I have seen this remark about the tables 100 times.
#39 17725077 23 Jan 2019 22:03

Strumien swiadomosci swia Strumien swiadomosc...

Level 43

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Post #39
17725077 23 Jan 2019 22:03

LChucki wrote:
Probably not because a small group of interested parties - industrial automation.

TO inverter as found. Instead of long potentiometer wires.
#40 17725091 23 Jan 2019 22:07

kkknc kkknc

Level 43

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Post #40
17725091 23 Jan 2019 22:07

dabek3456 wrote:
How do you know if I have more posts on another account? .

Write this from another account.
#41 17725119 23 Jan 2019 22:14

Strumien swiadomosci swia Strumien swiadomosc...

Level 43

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Post #41
17725119 23 Jan 2019 22:14

But this is a CMS post, why are you interrupting him?
#42 17725663 24 Jan 2019 08:57

vodiczka vodiczka

Level 43

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Post #42
17725663 24 Jan 2019 08:57

dabek3456 wrote:
I wrote this post because I can see that the author is terribly resistant to the suggestions of others, I have seen this remark about the tables 100 times.
This topic has already been viewed by over 2,200 people, 40 replied and only you do not like the way the results are presented.
You didn't get a single layman for your snappy statement.
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#43 17726456 24 Jan 2019 15:21

Anonymous Anonymous

Level 1

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Post #43
17726456 24 Jan 2019 15:21

dabek3456 wrote:
How do you know if I have more posts on another account? A weak argument. I wrote this post because I can see that the author is terribly resistant to the suggestions of others, I have seen this remark about the tables 100 times.

and you have your table for Chinese, the desired calibration certificate, now determine whether, on the basis of this certificate and the conditions of the ISO 9001 standard, "something there, something there" allow the device to be used. Justify why or why not. And don't bother your guitar anymore, because instead of sleeping in the "Czerobrgadówka" club I was creating such crap.
2019-001-P... 20 ma.pdf (41.6 kB)You must be logged in to download this attachment.
#44 17726898 24 Jan 2019 18:08

kkknc kkknc

Level 43

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Post #44
17726898 24 Jan 2019 18:08

I will stick, no signature ... And a blunt.
#45 17727053 24 Jan 2019 18:51

CMS CMS

VIP Meritorious for electroda.pl

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Post #45
17727053 24 Jan 2019 18:51

odalladoalla wrote:

dabek3456 wrote:
How do you know if I have more posts on another account? A weak argument. I wrote this post because I can see that the author is terribly resistant to the suggestions of others, I have seen this remark about the tables 100 times.

and you have your table for Chinese, the desired calibration certificate, now determine whether, on the basis of this certificate and the conditions of the ISO 9001 standard, "something there, something there" allow the device to be used. Justify why or why not. And don't bother your guitar anymore, because instead of sleeping in the "Czerobrgadówka" club I was creating such crap.

You made me laugh, buddy. For your dedication and time spent in producing this "document", especially after the night shift, I transfer you 500 points. .
#46 17727202 24 Jan 2019 19:38

Anonymous Anonymous

Level 1

» |

Post #46
17727202 24 Jan 2019 19:38

kkknc wrote:
I will stick, no signature ... And a blunt.

Since it is a pdf, there is no signature and no stamp ... after printing it should be there. Yes, the stamp of the organization with the accreditation number and a personal stamp with the signature of the authorization, e.g. the lab manager. Seal official was only on "serious" certificates of legalization of the Central Office of Measures
(squeezed stamp on paper) and sometimes on "wax cast" "consolidating" the number of sheets of documents.
But that wasn't really what the question was about.
We are waiting further.
More about the technical aspects of evaluation.
By the way, what should be included in the ACCREDITED calibration certificate lab. in the Polish Center for Accreditation - yes with various errors, but enough at the beginning
https://www.narzedziak.pl/blog/cala-prawda-o-wzorcaniu.html
Oh, I didn't work there and I don't work there, a site quite randomly substituted by google, and I don't advertise this company - it just clicked.
A stamp is a "device" to create an imprint, so it cannot be on the certificate (there may be an imprint of the stamp) - popularly mistakenly the saying is postmarked in circulation, and this is probably the reason for such an erroneous reference.

Added after 7 [minutes]:

CMS wrote:

odalladoalla wrote:

dabek3456 wrote:
How do you know if I have more posts on another account? A weak argument. I wrote this post because I can see that the author is terribly resistant to the suggestions of others, I have seen this remark about the tables 100 times.

and you have your table for Chinese, the desired calibration certificate, now determine whether, on the basis of this certificate and the conditions of the ISO 9001 standard, "something there, something there" allow the device to be used. Justify why or why not. And don't bother your guitar anymore, because instead of sleeping in the "Czerobrgadówka" club I was creating such crap.

You made me laugh, buddy. For your dedication and time spent in producing this "document", especially after the night shift, I transfer you 500 points. .

A, thank you, thank you, maybe I will do something else someday apart from grumbling on the stove when I wake up
#47 17727670 24 Jan 2019 21:29

Szyszkownik Kilkujadek Szyszkownik Kilkujadek

Level 37

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Post #47
17727670 24 Jan 2019 21:29

kkknc wrote:
I will stick, no signature ... And a blunt.

Exercising my powers, I, Szyszkownik Kilkujadek, under the law of Szuflandia, by the solemnity of the Żołędny Certification Authority assigns the CE mark.
-
Signed for the Supreme Court, Kilkujadek H., pine cone, on the thirteenth day of the earthworm, in the year of Drawland the twenty-fifth.
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Topic summary

✨ The discussion revolves around the testing and review of a 4-20mA Signal Generator, inspired by a suggestion from a colleague. Users inquire about the device's functionality, including its power requirements, stability of output, and potential applications in industrial automation. Questions arise regarding the device's ability to provide reference voltages and the acceptable load resistance. Some participants express skepticism about its widespread utility, while others highlight its potential for testing various sensors. Comparisons are made with other signal generators, and the conversation touches on calibration and measurement accuracy. The community emphasizes the importance of practical applications and the need for reliable performance in automation tasks.

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Current source, 4-20mA Signal Generator - Test / Review / Opis

FAQ

TL;DR: Tested 4-20 mA panel generator stays within ±0.02 mA (0.2 %) over 8–24 V loop voltage, "the circuit works fine" [Elektroda, CMS, post #17717702] Good for sensor simulation, multimeter calibration, but back-light is weak.

Why it matters: Quick, low-cost current source speeds up field troubleshooting and bench calibration.

Quick Facts

• Price: 23 PLN + 7 PLN shipping [Elektroda, CMS, post #17717702] • Loop voltage: Works from 8 V (10 mA) to 30 V; manufacturer states 15–30 V [Elektroda, CMS, post #17717702] • Output range/step: 4.00–20.00 mA in 0.05 mA steps; display shows 0.01 mA [Elektroda, CMS, post #17717702] • Self-consumption: ≈3 mA at minimum setting; <30 mA worst-case [Elektroda, CMS, post #17717702] • Protection: Internal bridge allows reverse connection [Elektroda, CMS, post #17718695]

How do I wire the generator in a current loop?

Insert it in series with the power supply and load; no separate supply is needed because it powers itself from the loop [Elektroda, CMS, post #17718695]

Does polarity matter when connecting?

No. A full-wave bridge (D2) lets the unit work with either polarity without damage [Elektroda, CMS, post #17718695]

What supply voltage is required for 4–20 mA operation?

The module regulates 10 mA from 8 V and 20 mA from 10.5 V; manufacturer quotes 15-30 V, giving comfortable headroom on 24 V loops [Elektroda, CMS, post #17717702]

How accurate is the output?

Measurements showed ±0.02 mA deviation across 8-24 V, equal to 0.2 % of span—adequate for most transmitter checks [Elektroda, CMS, post #17717702]

What resolution can I set?

The encoder advances in 0.05 mA increments even though the screen shows two decimal places [Elektroda, CMS, post #17717702]

What is the maximum load resistance (compliance)?

Compliance ≈ (Vloop − 8 V)/0.02 A. On a 24 V loop that equals about 800 Ω; at 15 V it drops to 350 Ω. Exceeding this causes current drop [Elektroda, CMS, post #17717702]

Can I use it as a 0.4–10 V reference source?

Yes. Add a precision resistor: 100 Ω gives 0.4–2.0 V, 500 Ω gives 2–10 V, but even a few kΩ of extra load alters accuracy [Elektroda, bestler, post #17718409]

Does it remember the last setting after power loss?

Pressing the knob stores the value in non-volatile memory; after reconnection it resumes that current [Elektroda, CMS, post #17718695]

Are there overshoots when the loop is energised?

No overshoot was seen on a Sanwa multimeter during power-on; current reached the set point smoothly [Elektroda, CMS, post #17717702]

What happens if a 470 Ω resistor is left in series?

At 15 V the unit showed >10 % error at 20 mA; removing the resistor restored accuracy, illustrating loop-voltage headroom limits [Elektroda, CMS, post #17717702]

Is the display readable in low light?

Back-light is very dim; text remains legible in daylight but nearly invisible in a dark room [Elektroda, CMS, post #17717702]

How much current does the device itself draw?

Self-consumption stays below 4 mA at minimum output and under 30 mA at 20 mA setting, including display [Elektroda, CMS, post #17718695]

Can the generator withstand industrial use?

It suits quick calibration of PLC or transmitter inputs where 0.1 % precision is sufficient; it lacks formal traceable certification required by ISO-accredited labs [Elektroda, PiotrPitucha, post #17721362]

How do I quickly simulate 50 %, 75 % and 100 % span?

Turn knob to 12.00 mA (50 %), press to store.
Repeat for 16.00 mA (75 %) and 20.00 mA (100 %).
Rotate knob to recall any stored point during testing. [Elektroda, CMS, post #17718695]

What edge cases should I watch for?

Running near compliance limit or inserting extra resistance can cause large errors; verify loop voltage first. Display back-light may be unreadable in control cabinets with lights off [Elektroda, CMS, post #17717702]

Is there a handheld 0-10 V / 0-20 mA alternative?

Yes; multi-function simulators cost about US $35 and include separate 0-10 V output, but user reviews on accuracy are scarce [jarcecz link, #17720109].