Model Continuous Workstation Monitor, Dual Wire ©Copyright 2003 DESCO INDUSTRIES INC.

Monitor Resistive Loop, Dual Operator/Dual Work Surface Monitoring of two operators and two ground connections independently. Dual Wire Continuous Monitors provide redundancy; even if one wrist strap conductor is severed, operator has reliable path-to-ground with other wire. Continuous Workstation Monitor, Dual Wire, Programmable

ESD Handbook TR paragraph Test Frequency “Because wrist straps have a finite life, it is important to develop a test frequency that will guarantee integrity of the system. Typical test programs recommend that wrist straps that are used daily should be tested daily. However, if the products that are being produced are of such value that knowledge of a continuous, reliable ground is needed, and then continuous monitoring should be considered or even required.” Per ESD-S1.1 paragraph Frequency of Functional Testing “Daily [Wrist Strap] testing may be omitted if constant monitoring is used.” Continuous Workstation Monitor

What Should I Monitor? Operator resistance to ground Workstation resistance to ground Operator charge buildup –Want or Need???

Considerations: –All conductors must be grounded at all times to protect against ESD –Due to continuous movement; operators are the greatest hazard to sensitive products –The loss of a ground connection can easily go unnoticed until yield is reduced. Then it is too late! WHY NOT! What Should I Monitor?

The decision is based on: –ESD sensitivity of the products being handled –Type of process –Compliance with existing standards Operator HIGH and LOW resistance Workstation ground resistance –Stainless steel or dissipative material Ground reference What Should I Monitor?

The definition of ground is: A) 8 Volts B) 4 Volts C) 1.8 Volts D) 0 Volts How is GROUND Defined? All conductors must be grounded A continuous monitor is the grounding device

Continuous Monitors The monitoring technology selected must be compatible with device technologies There is a wide variety of monitors available –Various test methods –Various test voltages –Various alarm condition –Varying potential impact on process and product Resistive loop monitors provide excellent protection Resistive loop technology –Continuous test voltage –Pulsed test voltage (mostly off)

3M unit pulses test voltage 3M is actually off over 90% of the time 3M pulses electrical current for only 0.2 seconds followed by an unmonitored interval of 2 seconds Thus any resistance break must be a continuous 2+ seconds. Not all intermittent failures are caught! 3M Resistive Loop Monitoring

Provides true 100% continuous monitoring 100% Monitoring means detection of all intermittent failures! The response time of Desco unit is 100 ms or 0.1 second It takes up to 2 seconds for the 3M unit to respond ESD happens in 100 nanoseconds or seconds Desco Resistive Loop Monitoring

The supply voltage then passes to the operator Resistive Loop Monitoring - Theory

Safe Monitor Status 3M 722 The supply voltage continues onto the second half of the wrist strap assembly and finally to ground. THE OPERATOR WILL HAVE A RESIDUAL VOLTAGE. Resistive Loop Monitoring - Theory

Safe Monitor Status When the operator comes in contact with hand tools or fixtures while working on sensitive products... 3M Resistive Loop Monitoring - Theory

Safe Monitor Status … the tool will rise to the voltage potential of the operator. When the tool contacts the sensitive part... 3M Resistive Loop Monitoring - Theory

Safe Monitor Status A micro spark will be produced by the tool & ESDS device, generating a current transient. MM, not HBM. CURRENT TRANSIENT will range from  5mA to  55mA 3M 722 !!!! WHAM!!!! Resistive Loop Monitoring - Theory

HBM Vs. MM Human Body Model 1500 Ω 100 pf High resistance limits the amount of current and energy produced during a discharge Machine Model 0 Ω 200 pf Low resistance increases the amount of current and energy produced during a discharge Using Machine Model Operator becomes charged by the monitor and charges a tool that then contacts an ESDS device. Low resistance, higher current and energy, increased ESD risk!

Safe Monitor Status The utilizes advanced circuitry which dramatically reduces the operator voltage CURRENT TRANSIENT will range from  1mA to  10mA Resistive Loop Monitoring - Less is Better!!!

Performance Summary 3M 722 V supply V operator (Typical) Current Transient (Typical) Desco v 8v 55mA 8v 4mA

Alarm Conditions Operator –High Resistance –Low Resistance –Charge Detection Ground –High Resistance –Charge Detection

Operator High Resistance 3M 722 YES 10 meg Ω YES 10 meg Ω

Low Resistance 3M 722 YES 1 meg Ω YES 1 meg Ω

Charge Detection 3M 722 NO NO

Ground Failure 3M 722 YES 3.5meg Ω YES 3.5meg Ω 10 v 3 V

Alarm Status Comparison

Systems Components Monitoring unit One remote with two receptacles Mat ground wire System ground wire Mounting hardware Power supply 3M 722

System Components Monitor unit Two operator remote receptacles System ground wire Mat/table connection hardware Two mat interconnect wires Two mat ground wires Mounting hardware Power supply Desco 19665

Feature: Patented Resistance Loop Benefit: Provides continuous testing and verification of operators’ connection to ground Continuous Workstation Monitor, Dual Wire, Resistive Loop Dual Wire Monitor LED displays

Feature: Monitoring of two operators and two ground connections independently Benefit: Able to maintain two work operators and two surfaces at the same time to eliminate the risk of ESD damage from undetected wrist strap assemble failures Continuous Workstation Monitor, Dual Wire, Resistive Loop

Feature: Adjustable alarm level Benefit: Allows operator to control volume of alarm Continuous Workstation Monitor, Dual Wire, Resistive Loop

Feature: Independent alarming conditions: Audible and Visual Benefit: Operator will be able to see if noise level is high, or in contrast, able to hear the alarm without looking at monitor Continuous Workstation Monitor, Dual Wire, Resistive Loop

Feature: Fully compatible with the SCCN (Desco Semtronics Static Control Communication Network) Benefit: Can be used to automatically collect and monitor key operator status and fault information Continuous Workstation Monitor, Dual Wire, Resistive Loop

Feature: Independent Safe lights for each operator and each ground connection Benefit: Allows operator to visibly see status of each operator Continuous Workstation Monitor, Dual Wire, Resistive Loop

Dimensions: 4.3”W x 4.4”D x 1.8”H Power Supply: 110 VAC/60Hz input, 12 VDC500mA output Rated Power Consumption: 3.6VA Suitable for indoor use only at altitudes not exceeding 6500 ft (5km) Maximum relative humidity is 80% up to 88° F (31° C) decreasing linearly to 104° F (40° C) Pollution Degree: 2 per IEC 644 Temperature Range: 41° F (5° C) to 104° F (40° C) Chassis: Stainless Steel Housing Important: This appliance has a metal casing but the earth connection is only used for operational purposes. It is considered to be class I and testes as class II. The power supply connection plug is accessible to the user and there is no safety insulation inside the Therefore the insulation of the power supply is critical Specifications

Conclusion The Monitor provides the absolute best grounding and ground protection… WITHOUT EXCEPTION!!