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ANSI/ESD S20.20-1999 standard - for Development of an ESD program for Protection of Electrical and Electronic Parts, Assemblies, and Equipment (Excluding Electrically initiated Explosive Device) (May 18, 2000)

This new standard is an important document on static control.  It applies to activities where device will be damaged by electrostatic discharges greater than or equal to 100 V Human Body Model.  In brief,

It states fundmental control principles :
- all conductors must be electrically grounded.
- all necessary nonconductor must be covered by ionization systems.
- all ESD-sensitive item must be enclosed in static-protective materials when they are outside the ESD-protected area.

It points out the admininstrative plans for a successful ESD control program :
- Program Plan
- Training Plan
- Compliance Verification Plan

It recommends the technical requirements for various ESD control system :
- Grounding/Bonding System :
   - for Equipment Ground, Auxiliary Ground or Common-Point Ground : < 1 ohm AC Impedence
   - for Equipotential Bonding : < 1 x 109 ohm
- Personal Grounding :
   - wrist strap system : < 35 x 106 ohm
   - floor/footwear system : < 35 x 106 ohm or < 100V
- Protected Area :
   - Work Surface : < 1 x 109 ohm or < 200V
   - Wrist Strap Cord : 0.8 - 1.2 x 106 ohm
   - Footwear, Flooring, Seating, Shelving, Mobile Equipment : < 1 x 109 ohm
   - Garment : 1 x 105 to 1 x 1011 ohm
   - Ionization (other than Room Systems) : < +/- 50V offset voltage
   - Ionization (Room Systems) : < +/- 150V offset voltage
   - Humidity : > 30% and < 70 %
- Packaging :
   - Conductive : < 1 x 104 ohm
   - Dissipative : 1 x 104 to 1 x 1011 ohm
   - Shielding : < 50 nJ
- Marking : All ESD-sensitive assemblies and equipment, and ESD protective packaging.
- Equipment's resistance to ground :
   - AC powered tools : < 1 ohm
   - Battery powered and pneumatic hand tools : < 1012 ohm
   - Automated Handler : continuous conductive path to ground
- Handling procedure for all ESD-sensitive materials shall be established
- Sensitivity testing to energy-sensitive deveice under Human Body Model, Machine Model and Charged Device Model

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Meaning of Ion Balance (offset voltage) of our Aerostat PC, XC and Guardian ( October 20, 1998)

Usually, ionizers are required to be calibrated after operating for a certain period. The specification of ion balance is referred as the confidence level that the ion balance will not be drifted over the specified range UNDER RECOMMENDED REGULAR CLEANING AND CALIBRATION. Even, the ionizers are required to calibrate at set up to optimize the initial performance according to its actual operating environment.

Our Aerostat PC, XC and Guardian DO NOT NEED TO CALIBRATE. With the patented circuitry, these products will theorectically have zero offset voltage. However, due to component and production variance, they are born with a value within 5V range. Once they operate with an offset voltage, say 2 V, they will run with this offset voltage, and will not drift up and down. The case can be resembled to one resistor with have 10% tolerance in its resistance value. Unless a hardware failure is happened, these ionizers will not out of ion balance.

Thus, our SIMCO products is really a PLUG and PLAY product without the requirement of calibration work, even at set up. Only cleaning is required with our cleaning brush, and checking is subjected to the customer's internal requirement.

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