19210

19210 Datasheet


Figure Desco Workstation Real Time Continuous Monitor, Item Numbers 19210 and 19211

Part Datasheet
19210 19210 19210 (pdf)
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TECHNICAL BULLETIN TB-2073

Workstation Real Time Continuous Monitor

Operation, Installation and Maintenance

Made in America

Figure Desco Workstation Real Time Continuous Monitor, Item Numbers 19210 and 19211

Leading companies use continuous monitors as a cost effective component in satisfying the paragraph Compliance Verification Plan requirements of ANSI/ESD S20.20. The Desco Workstation Real Time Continuous Monitor provides 100% monitoring of both the operator and the work surface. This unit provides continuous monitoring of one user wearing a wrist strap and also functions to ensure the grounding integrity of ESD protected work surfaces. This device will continuously monitor the user until the wrist strap or work surface becomes dysfunctional or unsafe according to accepted industry standards, at which point the monitor will issue an audible signal notifying the user of a problem. The Workstation Real Time Continuous Monitor also verifies whether an outlet ground is good. When plugged in, the unit automatically runs a self-test. If the outlet is wired incorrectly, both red LEDs turn on and the alarm sounds. The unit will also ground a second user or supervisor.

The Model 19210 operates on 120 VAC, 50/60 Hz, while the Model 19211 operates on 220 VAC, 50/60 Hz.

ADVANTAGES OF WORKSTATION CONTINOUS MONITORING OVER PERIODIC TESTING Many customers are eliminating periodic testing and are utilizing workstation continuous monitoring to better ensure that their products were manufactured in an ESD controlled environment. Full time workstation continous monitoring is superior to pulsed monitoring as well as periodic testing, and can save a significant amount of money in testing costs and rejected products. Periodic testing detects failures after ESD susceptible products have been manufactured. The costs of dealing with the resulting catastrophic or latent
defects can be considerable. Workstation Real Time Continuous Monitors eliminate the need for users to test wrist straps and log the results by their function, these monitors satisfy the ISO 9000 and ANSI/ESD S20.20 Paragraph test logging requirements.

WAVE DISTORTION DETECTION TECHNOLOGY PROVIDES TRUE 100% CONTINUOUS MONITORING From all the technical alternatives available, Desco has chosen wave distortion technology for all its Continuous Monitor product offerings. Wave distortion circuitry monitors current/voltage phase shifts and provides true 100% continuous monitoring. Electrical current will lead voltage at various points due to the combinations of resistance and capacitive reactance. By monitoring these “distortions” or phase shifts, the wave distortion Workstation Real Time Continuous Monitor will reliably determine if the circuit is complete.

Wave distortion technology can be referred to as “vector impedance monitoring”. This description is valid as the wave distortion technology measures the impedance at the monitored banana jack and looks for changes in either the capacitance or resistance of the circuit which includes the wrist strap and its wearer. It uses filtering and time domain sampling to filter out false signals caused by voltage offsets, 60 Hz fields and other electro-magnetic and electrostatic interference.

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 , the Workstation Real Time Continuous Monitor cannot be “fooled”. It will provide a reliable alarm only when the wrist strap or work surface becomes dysfunctional or unsafe according to accepted industry standards. The Workstation Real Time Continuous Monitor is drift-free and designed to be insensitive to the effects of squeezing or stretching the coil cord.

ADVANTAGES OF WAVE DISTORTION AND SINGLEWIRE TECHNOLOGY The Desco Workstation Real Time Continuous 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 expensive & fragile dual-wire cords and special wrist straps. Dual-wire cords are expensive and are the weak link of the system, the most likely component to need replacement. Over a five year period, this can make the dual-wire system three to five times as expensive as a system utilizing single-wire wrist straps and cords. See Calibration section on page 4 to minimize life cycle costs.

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710
• 909 627-8178
• Fax 909 627-7449 DESCO EAST - 90 Hudson Road, Canton, MA 02021-1407
• 781 821-8370
• Fax 781 575-0172
• Web Site:

TB-2073 10/01 Page 1 of 4

The dictionary defines constant as uniform and unchanging, and continuous as uninterrupted. Nonetheless, some dualwire resistance monitors utilize a pulsed test current and do not really provide continuous monitoring. For example, during each second pulse cycle of a leading “constant” resistive monitor, electrical current is pulsed for only seconds followed by an unmonitored interval of 2 seconds. This leaves the user/wrist strap unmonitored for over 90% of each cycle. Damaging static charges can easily occur in 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 microprocessors”.* The dual-wire system does not reliably meet all industry specifications, as the cords do not meet the EOS/ESD S-1.0 paragraph 1 to 5 pound “breakaway force” requirement for operator safety.

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 less than 1 volt coil cord signal required to generate the waveform has never caused reported skin irritation and is extremely safe for use in voltage sensitive applications such as disk drive manufacturing.

Installation

Remove the Monitor from the carton and inspect for shipping damage. Confirm that worksurface RTG surface resistance is 5 x 108 ohms or less. Each unit should include the following:
1 19210/19211 Monitor 1 09816 mat monitor cord 1 09863 snap push & clinch 1 Attached power cord

The Workstation Real Time Continuous Monitor may be mounted in a convenient position using the pressuresensitive two piece hook and loop fastener supplied. It is normally mounted toward the front edge of a workstation where the LEDs are easily visible.

Figure Installation of the Workstation Real Time Continuous Monitor. Shown as worn by operator.

Operation

When the Workstation Real Time Continuous Monitor is first plugged into a properly wired electrical outlet, both red LEDs will light and the alarm will sound.† The alarm will be sounding at this time since no wrist strap wearer or work surface is hooked up.

With a wrist strap on the wrist and the coil cord attached to the band, insert the banana plug of the wrist strap ground into the banana jack marked “User”. This will cause the operator green LED to light if the wrist strap is functioning properly.

Now connect a mat ground cord to the work surface. NOTE The work surface should be already grounded with another mat ground cord. Insert the banana plug of the mat ground cord Item #09816 into the banana jack marked “Work Surface” see Figure This will cause the “Work Surface” green LED to light if the work surface is properly grounded, and within the specified limit.

Figure Installing ground cords on the work surface. The user may disconnect the coil cord from the wrist band and leave the workstation by first touching the Standby Snap. This deactivates the alarm for six seconds and allows the operator to attach the coil cord to the Standby Snap. Using this procedure, the alarm will not sound, which otherwise could be interpreted as a problem. Note that if the coil cord is removed from the wrist band and not placed on the Standby Snap within six seconds, the alarm will sound.
*1981 article by Donald E. Frank - Electrical Overstress Electronic Discharge Symposium Proceedings
†The monitor takes 6 seconds to activate its alarm circuitry when it is first plugged in.

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710
• 909 627-8178
• Fax 909 627-7449 DESCO EAST - 90 Hudson Road, Canton, MA 02021-1407
• 781 821-8370
• Fax 781 575-0172
• Web Site:

TB-2073 Page 2 of 4

A. Work Surface Ground LEDs When the green LED is lit, the work surface is properly grounded. When red LED is lit, the work surface is not properly grounded. B. User Ground LEDs When the green LED is lit, the operator is properly grounded. When red LED is lit, the operator is not properly grounded. C. Monitored User Ground The banana jack for the wrist strap being monitored. D.Work Surface The banana jack for the work surface being monitored. E. Common Point Ground Will ground either user or work surface.

Specifications

RESISTANCE LIMITS Worksurface limit* Power Source
19210 19211 Current Drain Response time to alarm Standby “parking” snap delay Long Term Drift

Temperature
set to 500 megohms
120 VAC, 50-60 Hz 220 VAC, 50-60 Hz <15mA RMS <50 mS 6 seconds 1/2% per decade 1st decade is 1 hr 10-40 degrees C

Field Adjustment Size

None required 3/4" x 3-1/4" x 4-3/8"

Maintenance and Calibration†
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Notice: we do not provide any warranties that information, datasheets, application notes, circuit diagrams, or software stored on this website are up-to-date or error free. The archived 19210 Datasheet file may be downloaded here without warranties.

Datasheet ID: 19210 508545