For the surface resistance to ground measurements, TR53 specifies a different test voltage depending on the resistance range; 10V for RTG < 10^6 ohms and 100V if RTG initially measured ≥ 10^6 ohms.
Is this irrespective of what a given meter can measure at a particular test voltage?
For example, our meter specifies a range of 10^3 to 10^11 ohms for the 10V setting, and 10^5 to 10^12 ohms for the 100V setting. So, for <10^9 ohm qualification tests, could we stick to the 10V setting entirely?
Hafridi,
TR53 specifies 100V for anything over 10^6 ohms because 10V does not provide enough voltage to make an accurate measurement. So even if the meter says it is good to measure to 10^11 ohms at 10V, I wouldn’t trust the measurement.
Hello,
Greetings of the day to all , from India.
Well, our ESDA expert Mr.AndyN has already given you the answer.
But, just for sharing of the information in the forum I would like to mention two lines to state that, to get an accurate and repeatable measurements the use of 10 volts is sufficient for conductive materials (<10^6 ohms) but 100 volts is needed to drive more energy to get accurate and consistent readings between 10^6 -<10^9 ohms on Work and floor surfaces and, up to 10^11 ohms which is the upper limit applicable for packaging materials.
There are resistance meters available also with auto switching facility 10/100v .
For your information and reference, following is a copy of ESDA replies from ESDA experts which I had received to my following questions couple of years before. Hope it would help you too.
Q1. Why should it be at 100v only when resistance ranges are ≥1.0 x 106 ohm to <1.0 x 109 ohms or < 1 x 1011 ohms for packaging materials.?
A1. Initial round-robin testing of surface resistance was able to show that 10 volts applied to electrodes would give repeatable and reproduce-able results for materials <1 x 10E6 ohms and 100 volts applied to electrodes gave repeatable and reproduce-able results for materials >/= 1 x 10E6 ohms to 1 x 10E12 ohms. When testing something new or unknown, it is recommended to start with 10 volts and if >1 x 10E6 ohms, de-energize the meter and switch to 100 volts and record that value, even if it is <1 x 10E6 ohms. There are materials right on the edge of the 1 x 10E6 ohms value.
Q2. Many a times, I have seen that there is hardly any difference in readings with 10 v or 100v activation or with 10 v and 100v operated separate SR meters. Then, why not go with a 10v instrument only as it would be comparatively economical also cost wise.?
A2. There are a variety of instruments for sure. There are those that apply a constant current and voltage and some that vary in applied current and voltage as resistance increases. The latter are called open circuit and are only used for compliance verification type testing. The under-load instruments are used for product qualification (and can be used for compliance verification if desired).
Q3. Why should the 5 lbs SS insulated electrodes only be recommended and why not with normal leads or pointed leads directly to touch any two points on the surface of the material?
A3. It has been shown in 40 years of testing static control materials that many materials in use are not purely homogeneous and a pin probe will not give sufficient surface contact. Again, initial round robin testing back in the 1970’s and 1980’s established the dimensions of the electrodes used today. There is no evidence to support the use of other electrodes for work surfaces and floor materials. Certainly, conductive and homogeneous materials can be measured with a pin probe and low voltage, as from a standard volt-ohmmeter. The correct instrument needs to be used for the correct application.
Q4. What is the reason behind keeping the two 5 lbs electrodes 12" apart on work surfaces and 36" apart on floor material surfaces for point-to-point resistance check?
A4. One more time, the initial round-robin testing done for worksurface testing (STM4.1) and flooring materials (STM7.1) established the point-to-point distances. They were established a long time ago and have stood the test of time in the industry and not likely to change without a lot of evidence that contradicts the methods. In a practical sense, the area on a work surface where unprotected parts may be handled is smaller - thus the 30 cm separation and the area on a floor needs to compensate for seams that may be present - as in floor tile.
Good day to all ,
Thank you