ANSI ESD STM-11.11-2006 pdf download For the Protection of Electrostatic Discharge Susceptible Items – Surface Resistance Measurement of Static Dissipative Planar Materials
6.3 Instrumentation The instrumentation may consist of either a power supply and an ammeter, or an integrated instrument that combines these functions.
6.3.1 The instrument(s) open circuit voltage shall be 100 volts ( 5%) for measurements of 1.0×105 ohms and above, and 10 volts (5%) for measurements less than 1.0×10% ohms.
6.3.2 The instrumentation must be capable of making measurements from 1.0×10* to 1.0×1013 ohms.
6.4 System Verification Fixtures
6.4.1 Lower Resistance Range Fixture This fixture shall conform to the electrode assembly dimensions and have 20 individual pads which make contact with the inner electrode surface, and 20 individual pads which make contact with the outer electrode surface. The fixture shall consist of 20 each, 10 megohm, 1% resistors. Each resistor shall be individually connected between an inner and an outer pad (see Figure 2).
6.4.2 Upper Resistance Range Fixture This fixture shall conform to the electrode assembly dimensions and have metal surfaces or pads, which make contact with the electrode surfaces. The fixture shall employ a single resistor of 1.0x 1012 ohms (5 percent) connected between the inner and the outer contact surfaces (see Figure 3).
A. A minimum of six representative specimens of the sample material shall be prepared.
B. The minimum specimen size shall be at least 76 x 127 mm (3.0 x 5.0 inches).
C. The material surfaces must be clearly marked to identify the specimen’s orientation (e.g., Top,Bottom, Side A, Side B, Inside, Outside, etc.).
8.0 LOWER RESISTANCE RANGE SYSTEM VERIFICATION PROCEDURE
Prior to performing surface resistance measureiments, the system shall be checked for proper operation as follows:
A. Turn the instrument(s) on and allow for warm-up per the manufacturer’s instructions.
B. Connect the electrode assembly to the instrument(s) according to Figure 1. .
C. Place the electrode assembly onto the lower resistance range verification fixture (see Figure 2).
D. Energize the electrode assembly at 10 volts and allow the measurement to stabllize for 5 seconds. The calculated or measured value must be 5.0x 105 ohms, 1%.
E. Rotate the electrode assembly 90 degrees and repeat Step D.
NOTE: Rotation of the electrode assembly checks the flatness of the fixture.
9.0 UPPER RESISTANCE RANGE SYSTEM VERIFICATION PROCEDURE AND
DETERMINATION OF EL ECTRIFICATION PERIOD
The following procedure confirms the system’s capability to measure 1.0 x 1012 ohms and establishes the electrification period.
A. Turn the instrument(s) on and allow for warm-up per the manufacturer’s instructions.
B. Connect the electrode assembly to the instrument(s) according to Figure 1.
C. Place the electrode assembly onto the upper resistance range verification fixture.