Transcript Continuous Workstation Monitor, Programmable, USA Standard

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