TECHNICAL BULLETIN TB-3058 Dual Operator Continuous Monitor Made in the Installation, Operation and Maintenance United States of America The Dual Operator Workstation Continuous Monitor is a real time instrument that ensures that critical ESD control components in a sensitive area are effectively grounded. It independently monitors the operator and the worksurface. The instant an operators wrist strap or cord fails, the monitor will issue audible and visual alarms alerting the user of the problem. In the same manner, the unit also confirms that 7 a path to ground of less than 10 megohms (1 x 10 ohms) exists from the ESD protective worksurface(s). ADVANTAGES OF CONTINUOUS MONITORING OVER PERIODIC TESTING Figure 1. Desco Dual Operator Continuous Monitor with Many customers are eliminating periodic touch testing of Satellites wrist straps and are utilizing continuous monitoring to better Description ensure that their products were manufactured in an ESD protected environment. Full time continuous monitoring Leading companies use continuous monitors as a cost is superior to periodic or pulsed testing, and can save a effective component in satisfying the section 6.1.3 significant amount of money in testing costs and rejected Compliance Verification Plan requirements of ANSI/ESD product. Periodic testing detects wrist strap failures after ESD S20.20. The Desco Dual Operator Continuous Monitor with susceptible products have been manufactured. The costs Satellites continuously monitors the grounding integrity of two of dealing with the resulting catastrophic failures or latent operators, and two ESD worksurfaces path to ground. The defects can be considerable. Dual Operator Workstation monitor will provide instantaneous notification of static control Continuous Monitors eliminate the need for users to test equipment failures, and eliminates the need of costly and wrist straps and log the results by their function, these difficult to supervise wrist strap logging record keeping. This monitors satisfy the ISO and ANSI/ESD S20.20 test logging. unit is highly cost effective as it is designed to monitor any ANSI/ESD S20.20 Paragraph 6.2.2.2 Personnel Grounding conventional single-wire wrist strap and ground cord system. Guidance states A log should be maintained which verifies Per ESD Handbook ESD TR20.20 section 5.3.2.4.4 Test that personnel have tested their personal grounding devices. Frequency, Because wrist straps have a finite life, it is Per ESD-S1.1 Paragraph 6.1.3 Daily (wrist strap system) important to develop a test frequency that will guarantee testing may be omitted if constant monitoring is used. integrity of the system. Typical test programs recommend WAVE DISTORTION DETECTION TECHNOLOGY that wrist straps that are used daily should be tested daily. PROVIDES TRUE 100% CONTINUOUS MONITORING However, if the products that are being produced are of such From the technical alternatives available, Desco designs value that knowledge of a continuous, reliable ground is and manufactures many of its Continuous Monitor product needed, then continuous monitoring should be considered or offerings using wave distortion technology . Wave distortion even required. circuitry monitors current/voltage phase shifts and provides The Desco Dual Operator Continuous Monitor is available in true 100% continuous monitoring. Electrical current will the following models: lead voltage at various points due to the combinations of resistance and capacitive reactance. By monitoring these Item Power Adapter Input distortions or phase shifts, the wave distortion Workstation Continuous Monitor will reliably determine if the circuit is 19246 120VAC complete. 19247 220VAC The Dual Operator Continuous Monitor with Satellites is an impedance sensing device designed to monitor body types from a 5th percentile female to a 95th percentile male. This *NASA Publication 1024-Anthropomorphic Source Book Volume 1: range covers a 5 foot tall 90 pound person to a 6 foot 5 Anthropometry for Designers inch 250 pound person in any production environment.* The 19246 is powered by a 120 VAC, 60/50 Hz, plug-in ** Per ANSI/ESD S20.20 paragraph 6.0.3. Tailoring This document, transformer which also provides connection to ground. or portions thereof, may not apply to all applica tions. Tailoring is accomplished by evaluating the applicability of each requirement No user adjustment required: The Continuous Monitor for the specific application. Upon completion of the evaluation, is drift-free and designed to be insensitive to the effects of requirements may be added, modified or deleted. Tailoring squeezing or stretching the coil cord. It requires no user decisions, including rationale, shall be documented in the ESD Control Program Plan. adjustment. DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 (909) 627-8178 DESCO EAST - One Colgate Way, Canton, MA 02021-1407 (781) 821-8370 Website: Desco.com 2019 DESCO INDUSTRIES INC TB-3058 Page 1 of 5 May 2019 Employee OwnedWave distortion technology can be referred to as vector Packaging impedance monitoring. This description is valid as the 1 Dual Operator Continuous Monitor (Control Unit) wave distortion technology measures the impedance at the 2 Satellite Remotes monitored banana jack and looks for changes in either the 1 Power Adapter, 24VAC capacitance or resistance of the circuit which includes the 2 Mat Monitor Cords (Black), 6 wrist strap and its wearer. It uses filtering and time domain 2 Mat Ground Cords (Green and Yellow), 6 sampling to filter out false signals caused by voltage offsets, 2 Satellite Remote Cables, 7 60 Hz fields and other electro-magnetic and electrostatic 4 Countersink Washers and Screws ( 4 x 1/4 ) interference. 6 Mounting Screws ( 8 x 3/4 ) 1 Certificate of Calibration In normal factory environments, and with persons whose capacitance with respect to ground is within design limits (5 feet tall 90 pound person to 6 foot 5 inch 250 pound person), Installation the Dual Operator Workstation Continuous Monitor cannot Remove the monitor and satellites from its packaging. be fooled. It will provide a reliable alarm only when the Inspect for any shipping damage. Confirm that the wrist strap or work surface becomes dysfunctional or unsafe 7 worksurface is 1 x 10 ohms or less and has a conductive according to accepted industry standards. The Dual Operator layer such as Dual Layer Rubber, Dissipative 3-Layer Vinyl, Workstation Continuous Monitor is drift-free and designed to or Micastat Dissipative Laminate with conductive buried be insensitive to the effects of squeezing or stretching the layers. coil cord. The Control Unit for the Dual Operator Continuous Monitor is ADVANTAGES OF WAVE DISTORTION AND normally installed under the bench top toward the front edge SINGLE-WIRE TECHNOLOGY of a workstation where the LEDs are easily visible. Use the The Desco Dual Operator Workstation Continuous Monitor enclosures flanges to mount the monitor. allows the use of any standard, single-wire wrist strap and coil cord. The monitor/wrist strap/cord system life-cycle costs are by far lower than alternative systems which require more expensive & less durable dual-wire cords and special wrist straps. Dual-wire cords are expensive and are the weak link of the system. They are the most likely component to need replacement. Over a five year period this can make a dual-wire system three times as expensive as a system utilizing single-wire wrist straps and cords. The dictionary defines constant as uniform and unchanging, and continuous as uninterrupted. Nonetheless, some dual-wire resistance monitors utilize a pulsed test current and do not really provide continuous monitoring. For example, during each 2.2 second pulse cycle of a leading constant resistive monitor, electrical current is pulsed for only 0.2 screws seconds followed by an unmonitored interval of 2 seconds. This leaves the user/wrist strap unmonitored for over 90% of each cycle. Damaging ESD events can easily occur in Figure 2. Mounting the Control Unit the portion of the time in between the pulses. The off period of 2 seconds equals 2 billion nanoseconds, and it takes only about 25 volts applied for 100 nanoseconds to blow most memories or microprocessor.* The dual-wire system does not meet all industry ESD S6.1 specifications, as the cords do not meet the EOS/ESD Association guidelines for the 1 to 5 pound breakaway force requirement for ensuring a reliable path-to-ground and preventing accidental disconnects. By using the reliable wave distortion technology to determine if the circuit is complete, there are no false alarms. There is no need to adjust or tune the monitor to a specific user or installation. The miniscule amount of electrical current Figure 3. Typical setup of the Dual Operator Continuous (less than 1 volt coil cord signal) required to generate the Monitor and Satellites waveform has never caused reported skin irritation and is extremely safe for use in voltage sensitive applications such as disk drive manufacturing. *1981 article by Donald E. Frank - Electrical Overstress Electronic Discharge Symposium Proceedings DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 (909) 627-8178 DESCO EAST - One Colgate Way, Canton, MA 02021-1407 (781) 821-8370 Website: Desco.com 2019 DESCO INDUSTRIES INC TB-3058 Page 2 of 5 Employee Owned