RST FG-100 soldering tip thermometer proudly Made in China - Mini Review

[Kiriakos GR]

Say Goodbye at the crushed cardboard box.

I had good luck along skills and the tool, and succeeded removing these fancy labels from the crushed cardboard box.
Now I have three reusable labels that I can use over the next storage solution for my RST FG-100.

Currently I do keep busy my brain with the question of what would be the most practical storage solution for this tool.
From the other hand, I am expecting in two weeks and a second one.
So I am still puzzled, storage solution per tool?  Or per both ?   

[Kiriakos GR]

I have much of educational fun here with all that testing. 

I did dare to use my LM35 high precision temperature sensor 10mV/Celsius 0,3 precision, along my super weapon 8846A this was set to five digits resolution 1PLC.
The RST FG-100 was powered on and kept active for more than 40 minutes, so this to be considered as stable for calibration inspection.
LM35 along 8844A all warmed up too.
 
Previously I had install my first 191-222 sensor, this is branded as HAKCO but it is formed with attention to detail = all good.   
LM35 sensor this was placed on top of the 191-222 sensor.
The test performed at 10:00 at night, it was a warm day and room temperature this is now stable.

FLK 8846A this measure the output of LM35, and RST FG-100 this takes input by their own sensor.


I were very impressed by the results of my previews test = injected signal and comparison 

I got myself in the process to explore and measure of what is called as TC Sensor error.
LM35 is the highest precision sensor (all in one) in my lab, and I consider it as best for ambient temperature measurement and also as Cold-Junction Compensation trusted source.

RST FG-100 as I did prove at my other tests, this has three ranges and digits resolution changes too.
First range:  00.0 up to at 99.9  (three digits resolution) 
Second range: 100 up to 999   (three digits  resolution)
Third range: 1000 up to 1370  (four digits  resolution)

At the lowest range we can review highest detail of 00.1 Celsius. 
In contrast at the 8846A I did lower the resolution at five digits 00.001 Celsius, because this is more than enough. 
     
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At the temperature of 24.8C and at the moment that RST FG-100 this was ready to drop last digit at 24.7C , the DMM was still measuring at the high side. 
And this translates that measured TC Sensor error at the RST FG-100, this is at the low side ( minus percentage).
At Celsius measurement there is no sub-units,  thee digits for up to 99.9 this is all that we have and use.
And so at what called as important digits, I consider specific RST FG-100 also as extremely accurate at this Cold-Junction Compensation comparison.

The actual spotted error at RST FG-100, this is smartly hidden at the digits that the LCD display does not show or have.
In the positive side of things, specific RST FG-100 with serial number 202406098822 and sensor, both PASS Calibration inspection with flying colors. 

[Kiriakos GR]

This presentation is a confirmation about actual
electrical characteristics of RST-FG100.

I did mention already about the time requirement for thermal stabilization of any DUT when this is inspected about calibration verification.

One bench top or HH DMM, this might have 500 components in it, and a PCB with medium to large dimensions.
RST-FG100 this has instead a small PCB, one active chip, one voltage stabilizer, and no more than fifteen passive components in it.
It is a logical expectation, at 24C room temperature, this to require a much shorter time for thermal stabilization, and this is twelve minutes.

No one ever before, explored Electrical characteristics of this thermometer.
My electrical measurements revealed a small miracle in favor of battery consumption and overall performance.
At this test I did remove 9V dry battery and use as input external precision DC power supply.

At 9.000 V DC I did measure as first DC current consumption at POWER-OFF, at 100uA range (100.000 display resolution) I did measure 1.900uA (1.9 uA).
And or at 1mA range, I did measure 0.0019 mA.

At POWER-ON condition I did measure at 1mA range 45.024uA (45 uA) and or 0.045mA.
Battery consumption gets lower when internal battery voltage gets lower too.
Prior BATTERY LOW Icon this activates, I did measure 41.160uA and or 0.041mA.

Next test was of me exploring voltage levels.
From a 9V battery at full charge, RST-FG100 will activates BAT-LOW ICON at 3.15V,  and it will operate until 3.00V, then LO text appear at the digital display and no further measurement it can be performed.
And therefore RST-FG100 working voltage this is at the range of 9V down to 3V.

Most regular alkaline 9V battery this is approximately a source for 400mAh.
By a rough calculation RST-FG100 this can operate by measuring temperature for 8.800 Hours, due a single battery.
But this calculation it would be valid if cut-off voltage was at 6.5V, but this thermometer has cut-off voltage at 3.0V, which this makes hard to calculate of how extended is it actual battery life.

In conclusion, do not bother drilling it so to use it with external PSU.
With a fresh alkaline battery this will be usable to you, for the entire period of specific battery expiration date.   

[overvolt]

I have now the impression that original RST FG-100 electronic design, this was made by thinking lithium cell as battery source.
This also might explain of why there is some-sort of 3V voltage regulator in it.

Because of this unusual choice of operating voltage, any considered as empty 9V battery (6.5V termination voltage) this is still usable at this thermometer.   

Kiriakos did again excellent work at this thermometer mini review! 

[Kiriakos GR]

After of me performing a pile of calibration verification's, I did prove that this RST FG-100 its not a toy.

Now lets talk business, yesterday I did use it so to perform calibration inspection of my two soldering stations.
My primary soldering station has digital calibration adjustment, my much older one this has trim-pots adjustment.

I did touch the sensor for over 20 times as I did inspect in a range of temperatures, from 100C and towards up to 450C.
Its very interesting that the most important details of how to properly measure with it, they were never presented by the use of ink.

No one ever wrote in a humanized language, few basic advice's:
a) Carefully place soldering tip over sensor pad and avoid touching sensor wire.
b) Do not use as scale the pad, do not use any sort of pressure.
c) When sensor pad this eventually fill with solder,  then use a solder pump so to remove excess solder, so to clean the pad.

How to properly measure with it .. 
They are two methods of using RST FG-100 thermometer.

First method it should named as quick visual confirmation, touch the pad for ten seconds, and inspect how high temperature rises.

Second method this is the most valuable one, activate Temperature-Hold, do not look the display, just have your finger resting over Temperature-Hold trigger button.
NOW place the tip at the pad, measure with your voice from 1 to 10,  now press trigger button.
NOW move your eyes at the display. 
Transfer the measurement in to paper,  now add or subtract the necessary compensation at your soldering station calibration menu.

For the next step of confirmation, just follow first method.
If you think that 2~3 C of wrong compensation per displayed indication at your soldering station this is important?  the use Second method again, so to record a new temperature measurement.

With this pack of logical steps, I did the job, and my sensitive sensor pad, this never stressed in any way.
I have now the impression that I can perform more than 500 of measurements with out killing the sensor.

After performing and my last measurement, by the use of my hand solder pump, I did a good cleaning of the pad.
When temperature fall at ambient, the sensor did not demonstrated any change, was as new and unused.
It did measure again the ambient with out error.

Today I have now experiences of my own, at using properly RST FG-100 and sensor.
And I have now 100% awareness, that if you use with respect this tool, this it will never let you down.   

Its a fact that scam bags Chinese they cheat on us by delivering only five sensors, per new thermometer.
But if I knew of what I know today due personal experiences, I might never had order additional 10 pack of sensors.