9
Rev. B / June 2019
ACL 880 Digital Resistance Meter
CAUTION
Test Voltage is supplied through the Red Posive (+) terminal. To measure in accordance
with industry standard protocol Test Voltage is applied during the measurement starng
at <10 volts (variable), and then automacally increased to constant 10 volts, or constant
100 volts as necessary. When applied, Test voltage magnitude is indicated on the front
panel by the illuminated yellow LED above the applicable voltage.
D. Record your measurement as may be required.
NOTE: Measurements will be erased and the instrument reset to zero for the next measurement
aer 10 seconds.
The ACL 880 measurement process is quite fast and once a measurement is stable in the LCD, the
operator may elect to use the stable displayed measurement. In this case the EP is manually
determined by the operator. This is an efficient operating procedure for determining if the
measurement is generally within the required range for the object being audited. In this case, the
operator usually observes and confirms measurement stability, which results in faster audit
measurements. However, if the measurement is of a crical nature , or being used for material
qualificaon purposes, the full EP for that measurement should be employed, i.e., when the
measurement is completed and displayed, and the Green LED comes ON as described below.
If the operator desires the EP to be determined by the instrument in AUTO/GO A mode, the Green
Hold LED illuminates when the appropriate measurement period for each measurement is reached.
It takes into account the material variables seen during the measurement and adjusts the EP for
opmal measurement accuracy. Typical EP’s for the ACL 880 instrument are:
1.0E3 to 1.0E9 ohms: Typically 2 to 8 seconds (Range Average 6.0 seconds)
1.0E09 to 1.0E11 ohms: 7 to 10 seconds
>1.0E11 to 1.0E12 ohms: 10 to 25 seconds
These values are variable and based on the stability of the materials being measured, as well as the
envi-ronmental condions. For example, while the default EP for the ACL 880 instrument is 7.5
seconds, EP auto-macally adjusts to enhance measurement accuracy.
IV. Electrification Period in AUTO/GO A Mode
Electrification Period (EP) is the me required for an instrument to make a measurement from zero
(0) within 5% of 1.0x1012 ohms at 100 volts, plus 5 seconds. The EP is used for resistance measure-ments
equal to, or greater than 1.0x106ohms. The 880 was designed to incorporate variable EP to allow fastest
possible, accurate measurements. Typical EP up to less than 1.0x109ohms is typically less than 8.0
seconds. However, measurement condions in the factory environment vary considerably. To
compensate for variables in materials and condions, the 880 makes many measurements each second
and evaluates their consistency and stability. If necessary the 880 will automacally extend the
measurement me (EP) to insure an accurate representaon of the material under test.
