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Model 19665 Continuous Workstation Monitor, Dual Wire ©Copyright 2003 DESCO INDUSTRIES INC. Continuous Workstation Monitor, Dual Wire, Programmable • 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. www.desco.com Continuous Workstation Monitor ESD Handbook TR 20.20 paragraph 5.3.2.4.4 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 6.1.3 Frequency of Functional Testing “Daily [Wrist Strap] testing may be omitted if constant monitoring is used.” www.desco.com What Should I Monitor? • Operator resistance to ground • Workstation resistance to ground • Operator charge buildup – Want or Need??? www.desco.com What Should I Monitor? • 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! www.desco.com 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 www.desco.com How is GROUND Defined? • All conductors must be grounded • A continuous monitor is the grounding device • The definition of ground is: A) 8 Volts B) 4 Volts C) 1.8 Volts D) 0 Volts www.desco.com 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) www.desco.com 3M Resistive Loop Monitoring • 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! www.desco.com Desco 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 .0000001 seconds www.desco.com Resistive Loop Monitoring Theory • The supply voltage then passes to the operator www.desco.com Resistive Loop Monitoring Theory • The supply voltage continues onto the second half of the wrist strap assembly and finally to ground. • THE OPERATOR WILL HAVE A RESIDUAL VOLTAGE. 3M 722 Supply Voltage Vs Operator Voltage 20 Monitor Status 15 10 5 Safe V operator V supply 0 www.desco.com Resistive Loop Monitoring Theory • When the operator comes in contact with hand tools or fixtures while working on sensitive products... Supply Voltage Vs Operator Voltage 20 15 3M 722 Monitor Status 10 5 V operator V supply 0 Safe www.desco.com Resistive Loop Monitoring Theory • … the tool will rise to the voltage potential of the operator. When the tool contacts the sensitive part... Supply Voltage Vs Operator Voltage 3M 722 Monitor Status 20 15 10 5 V operator V supply 0 Safe www.desco.com Resistive Loop Monitoring Theory • 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 Supply Voltage Vs Operator Voltage 20 15 3M 722 Monitor Status 10 5 V operator V supply 0 Safe www.desco.com HBM Vs. MM Human Body Model Machine Model • 1500 Ω • 0Ω • 100 pf • 200 pf • High resistance limits • Low resistance increases the amount of current the amount of current and and energy produced energy produced during a during a discharge 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! www.desco.com Resistive Loop Monitoring Less is Better!!! • The 19665 utilizes advanced circuitry which dramatically reduces the operator voltage • CURRENT TRANSIENT will range from 1mA to 10mA Supply Voltage Vs Operator Voltage 19665 Monitor Status 8 6 4 2 V operator V supply 0 Safe www.desco.com Performance Summary 3M 722 Desco 19665 V supply 18v 8v V operator 8v 8v (Typical) Current Transient 55mA 4mA (Typical) www.desco.com Alarm Conditions • Operator – High Resistance – Low Resistance – Charge Detection • Ground – High Resistance – Charge Detection www.desco.com Operator High Resistance 3M 722 YES 10 meg Ω 19665 YES 10 meg Ω www.desco.com Low Resistance 3M 722 YES 1 meg Ω 19665 YES 1 meg Ω www.desco.com Charge Detection 3M 722 NO 19665 NO www.desco.com Ground Failure 10 v 3M 722 YES 3.5meg Ω 3 V 19665 YES 3.5meg Ω www.desco.com Alarm Status Comparison WORKSTATION CONDITION Operator 1 SAFE Operator 1 HIGH RESISTANCE Operator 1 LOW REISTANCE Operator 1 CHARGE Operator 1 NOT PRESENT Operator 2 SAFE Operator 2 HIGH RESISTANCE Operator 2 LOW REISTANCE Operator 2 CHARGE Operator 2 NOT PRESENT Ground 1 PASS Ground 1 FAIL Ground 2 PASS Ground 2 FAIL Total Conditions Possible Conditions Displayed Percent Performance 19665 3M 722 3M724 Shared Shared Shared Shared Shared Shared Shared Shared Shared Shared Shared Shared 14 12 N/A N/A 14 9 N/A N/A 14 9 86% 64% 64% www.desco.com Systems Components 3M 722 • Monitoring unit • One remote with two receptacles • Mat ground wire • System ground wire • Mounting hardware • Power supply www.desco.com System Components Desco 19665 • 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 www.desco.com Continuous Workstation Monitor, Dual Wire, Resistive Loop 19665 Dual Wire Monitor LED displays Feature: Patented Resistance Loop Benefit: Provides continuous testing and verification of operators’ connection to ground www.desco.com Continuous Workstation Monitor, Dual Wire, Resistive Loop 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 www.desco.com Continuous Workstation Monitor, Dual Wire, Resistive Loop Feature: Adjustable alarm level Benefit: Allows operator to control volume of alarm www.desco.com 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 www.desco.com Continuous Workstation Monitor, Dual Wire, Resistive Loop Feature: Fully compatible with the SCCN (Desco Semtronics Static Control Communication Network) 62600 Benefit: Can be used to automatically collect and monitor key operator status and fault information www.desco.com 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 www.desco.com Specifications • 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 50% @ 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 62030. Therefore the insulation of the power supply is critical www.desco.com Conclusion The 19665 Monitor provides the absolute best grounding and ground protection… WITHOUT EXCEPTION!! www.desco.com