TECHNICAL BULLETIN TB-3004 Workstation Continuous Mini Monitor Made in America Operation, Installation, and Maintenance Advantages Of Continuous Monitoring Over Periodic Testing: When considering constant or continuous monitors, the equipment cost including the wrist strap, maintenance and training cost, labor time for performing wrist strap tests, and the potential failures due to non-functional wrist straps should be considered. A broken wrist strap may expose products to ESD over an entire shift if it is checked only at shift change with wrist strap checker. (ESD TR 12-01 Section 4.2 Selection Considerations) The Jewel Workstation Continuous Monitor eliminates the need for periodic wrist strap tests and logging. Continuous monitoring is superior to periodic or pulsed Figure 1. Jewel Workstation Continuous Mini Monitor. testing, and can save a significant amount of money Description in testing costs and rejected product. Periodic testing detects failures after ESD susceptible products way The Jewel Workstation Continuous Mini Monitor independently monitors the operator and the have been manufactured. The costs of dealing with the worksurface. The instant an operators wrist strap or resulting catastrophic or latent defects can be cord fails, the monitor will issue audible and visual considerable. Jewel Workstation Continuous Mini alarms alerting the user of the problem. In the same Monitors eliminate the need for operaters to test wrist manner, the unit also confirms that a path to ground of straps and log the results by their function, these less than 500 megohms exists from the ESD monitors satisfy the ISO 9000 and ANSI/ESD S20.20 worksurface. test logging. ANSI/ESD S20.20 Section 6.2.2.2 Personnel Grounding Guidance states A log should be The Jewel Workstation Continuous Monitor is a Single Conductor Impedance Sensing Continuous Monitor maintained which verifies that personnel have tested which per ESD Handbook TR20.20 section 5.3.9.2.1 a their personal grounding devices. Per ANSI/ESD- small AC voltage is used in a detection circuit designed S1.1 Annex A Section 6.1.3 Daily (wrist strap system) to eliminate false alarms and adjustment. They use the testing may be omitted if constant monitoring is used. phase difference between current and voltage to detect Per ANSI/ESD-S1.1 Annex A Frequency of Functional changes in impedance of the grounding cord, wristband Testing, The wrist strap system should be tested daily and person. No adjustments are required. to ensure proper electrical value. Daily testing may be omitted if constant monitoring is used. Per ESD Handbook ESD TR20.20 section 5.3.2.4.4, Typical test programs recommend that wrist straps that are used daily should be tested daily. However, if the Park Snap products that are being produced are of such value that The audible alarm is designed to alert both operator and knowledge of a continuous, reliable ground is needed, supervisor. The Park Snap feature provides a means and then continuous monioring should be considered or for an operator to disconnect when normally leaving even required. the work area, without the audible alarm sounding, and The Jewel Workstation Continuous Mini Monitor is wrist cord storage (visual red LED will illuminate). When available in the following model. the operator touches the Park Snap, the audible alarm is disabled for about 8-10 seconds. The operator can Input/Output Model Color Calibration remove the wrist strap cord and attach socket of the Voltage AC cord to Park Snap for storage. The operator can 19212 Sapphire 120/24 NIST separate the coil cord from the wrist band and attach the coil cord snap to the park snap for convenient storage. The coil cord may also be removed from the jack on the Jewel monitor without the alarm sounding. Once the coil cord is in the park position, the operator ground status light will remain red. DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 (909) 627-8178 Fax (909) 627-7449 DESCO EAST - One Colgate Way, Canton, MA 02021-1407 (781) 821-8370 Fax (781) 575-0172 Web Site: Desco.com 2011 DESCO INDUSTRIES INC. TB-3004 March 2011 Page 1 of 4 Employee Ownedwrist strap unmonitored for over 90% of each cycle. Wave Distortion Detection Technology Damaging static charges can easily occur in the Provides True 100% Continuous portion of the time in between the pulses. The off period Monitoring of 2 seconds equals 2 billion nanoseconds, and it takes Wave distortion impedance circuitry monitors current/ only about 25 volts applied for 100 nanoseconds to blow voltage phase shifts and provides true 100% continuous most memories or microprocessors.* monitoring. Electrical current will lead voltage at By using the reliable wave distortion impedance various points due to the combinations of resistance technology to determine if the circuit is complete, there and capacitive reactance. By monitoring these are no false alarms. There is no need to adjust or tune distortions or phase shifts, the Jewel Workstation the monitor to a specific user or installation. The Continuous Mini Monitor will reliably determine if the miniscule amount of electrical current (less than 1 volt circuit is complete. coil cord signal) required to generate the waveform has Wave distortion technology can be referred to as vector never caused reported skin irritation and is extremely impedance monitoring. This description is valid as the safe for use in voltage sensitive applications such as wave distortion technology measures the impedance disk drive manufacturing. at the monitored banana jack and looks for changes in either the capacitance or resistance of the circuit which Worksurface Channel includes the wrist strap and its wearer. It uses The Jewel Workstation Continuous Mini Monitor filtering and time domain sampling to filter out false monitoring circuitry is sufficiently sensitive to detect signals caused by voltage offsets, 60 Hz fields and extremely low current, allowing it to be used with mats other electro-magnetic and electrostatic interference. having a resistance of up to 5 x 10E8 ohms RTG. In normal factory environments, and with persons When the Monitor is connected to an ESD Mat whose capacitance with respect to ground is within worksurface, the amount of current that flows is a design limits (5 feet tall 90 pound person to 6 foot 5 inch function of the total resistance between the monitor and 250 pound person), the Jewel Workstation through the worksurface to ground. When the resistance Continuous Mini Monitor cannot be fooled. It will of the worksurface is below a pre-set threshold, the provide a reliable alarm only when the wrist strap or monitor will indicate good. Conversely, if the resistance work surface becomes dysfunctional or unsafe level is high when compared to the monitors reference, according to accepted industry standards. The Jewel the unit will alarm. This is an integrating resistance Workstation Continuous Mini Monitor is drift-free and measuring circuit, therefore it is relatively insensitive to designed to be insensitive to the effects of squeezing or externally induced electromagnetic fields. The stretching the coil cord. resistance threshold is factory set to 500 megohms. (It can be special ordered to other limits. Limits can be Advantages Of Wave Distortion And varied and set to 1 gigohm maximum.) Single-Wire Technology Installation The Jewel Workstation Continuous Mini Monitor allows the use of any standard, single-wire wrist strap Confirm that the surface resistance (RTG) of the mat is and coil cord. The monitor/wrist strap/cord system 5 x 10E8 ohms or less and has a conductive layer. We life-cycle costs are by far lower than alternative systems recommend the Desco 19780 or 19635 Tester. Remove which require expensive and less durable dual-wire the monitor from its packaging and inspect for any cords and special wrist straps. The Jewel shipping damage. Included with each Jewel Worksta- Workstation Continuous Mini Monitor is an tion Continuous Mini Monitor should be: economical way to monitor both the operators wrist 1 120 VAC Adapter strap and workstation surface. See Maintenance and 2 Push and clinch snaps (09863) Calibration (page 4) to minimize life-cycle costs. The Continuous Mini Monitor is normally installed The dictionary defines constant as uniform and toward the front edge of a workstation where the LEDs unchanging, and continuous as uninterrupted. are easily visible. The unit is designed to be snapped on Nonetheless, some dual-wire resistance monitors utilize the worksurface using the 10mm snap studs mounted at a pulsed test current and do not provide continuous the bottom of the monitor. See figure 2. monitoring. For example, during each 2.2 second pulse cycle of a leading constant resistive monitor, electrical current is pulsed for only 0.2 seconds followed by an *1981 article by Donald E. Frank - Electrical Overstress / unmonitored interval of 2 seconds. This leaves the user/ Electronic Discharge Symposium Proceedings DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 (909) 627-8178 Fax (909) 627-7449 DESCO EAST - One Colgate Way, Canton, MA 02021-1407 (781) 821-8370 Fax (781) 575-0172 Web Site: Desco.com 2011 DESCO INDUSTRIES INC. TB-3004 Page 2 of 4 Employee Owned