2.2 Threshold Resistance Settings for the 3MShoes and Wrist Strap Tester 747

The test results indicated by the front panel LEDs are determined by comparison of the measured value with the threshold resistance settings (upper and lower limits).

LOW: the measured resistance is below the lower threshold

OK: the measured resistance is between the lower and upper thresholds

HIGH: the measured resistance is above the upper threshold

1.ESD Shoe Test Threshold Resistance Settings

The upper threshold (SHOES HIGH) and lower threshold (SHOES LOW) can be selected for shoe testing. Use tweezers to move the threshold switches

The upper threshold (SHOES HIGH) selections are 10, 35 or 100 Ω. The lower threshold (SHOES LOW) selections are 100 kΩ or 1 Ω.

2.ESD Wrist Strap Test Threshold Resistance Settings

The upper threshold (WRIST HIGH) can be selected for wrist strap testing.

Use tweezers to move the threshold switch.

The lower threshold is fixed at 1.65 Ω for wrist strap testing.

The upper threshold (WRIST HIGH) selections are 5, 10 or 35 MΩ.

Important Notes:

Factory default settings are 100 MΩ for SHOES HIGH, and 10 MΩ for WRIST HIGH, and 1 MΩ for SHOES LOW.

The SIGNAL OUT selection is set to SHOES. When operated as a stand-alone tester (that is, when not using the external output), this SIGNAL OUT selection should be set to either WRIST or

SHOES.

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3M 747 manual Shoes