USER GUIDE TB-9014 725 Wrist Strap Monitor Operation and Maintenance Theory of Operation The SCS 725 Wrist Strap Monitor is designed to monitor the operation of the wrist strap grounding system of a single operator. The system features special wrist bands and ground cords that contain two independent conductors. The 725 Wrist Strap Monitor performs a resistance measurement by applying a small electrical current. The path for the current is through one conductor of the wrist strap ground cord that contains a current-limiting resistor, through one side of the wristband, through the skin of the wearer under the band, through the second side of the wristband, through the second conductor of the wrist strap ground cord that contains a current limiting resistor, and finally back to the monitor. Figure 1. SCS 725 Wrist Strap Monitor If the resistance of the wrist strap loop is less than Description 35 megohms, the wrist strap ground cord, wristband, and the interface of the wristband to the arm of the The 725 Wrist Strap Monitor is designed to monitor the wearer are considered to be functioning correctly. If the operation of a wrist strap grounding system for a single measured resistance is over 35 megohms, a red lamp operator. This product has been designed and tested flashes along with a chirping audible alarm. for use with SCS Dual Conductor Wrist Straps and SCS Worksurfaces Grounding Systems. This unit is powered In addition, the 725 Wrist Strap Monitor monitors the by a 9 volt alkaline battery. Use of other components ground clip connection to a predetermined electrical or use in any other application not evaluated by SCS ground. This is accomplished by measuring the may cause improper performance and/or an unsafe resistance from the monitor, through one conductor of condition. To avoid damage to the 725 Wrist Strap the monitors ground cord and metal clip, through the Monitor, do not use this monitor outside of the operating ground point conducting medium, through the other conditions listed in this user guide. metal clip and conductor of the monitors ground cord, and finally back to the 725 Wrist Strap Monitor. If the Meets requirements of ANSI/ESD S20.20 and resistance of this loop exceeds 10 megohms, a red recommendations of ESD Handbook ESD TR20.20 lamp will illuminate with a continuous audible alarm. which includes if the products that are being produced This indicates that there is a problem with the monitors are of such value that knowledge of a continuous, ground cord or the ground. reliable ground is needed, and then continuous monitoring should be considered or even required. The SCS 725 Wrist Strap Monitor monitors the battery voltage and alerts the operator when it is necessary to The SCS Wrist Strap Monitor and its accessories are change the battery. When the battery voltage falls below available as the following item numbers: 6 volts 10%, the red lamp will illuminate with no audible alarm. At this time the 725 Wrist Strap Monitor is still Item Description operational, making reliable resistance measurements of 725 Wrist Strap Monitor the wrist strap assembly and the ground connection. 725VK Verification Kit 770065 Verification Tester Packaging 1 725 Wrist Strap Monitor with 5 ft. Ground Clip 1 Certificate of Calibration SCS - 926 JR Industrial Drive, Sanford, NC 27332 East: (919) 718-0000 West: (909) 627-9634 Website: StaticControl.com 2017 DESCO INDUSTRIES, INC. TB-9014 Page 1 of 5 December 2017 Employee OwnedUNDERNEATH A WORKBENCH Installation The SCS 725 Wrist Strap Monitor can be mounted ATTACHING TO A WORKSURFACE under a workbench by securing with two 8 screws (not The SCS 725 Wrist Strap Monitor can be used to supplied) through the mounting hole tabs located on the ground a worksurface while providing a monitored top cover. grounding point for an operator. To ground a worksurface, the 725 Wrist Strap Monitor contains a When mounting the 725 Wrist Strap Monitor under a snap located on its bottom cover, that is connected workbench for non-mobile use, remove the parking internally to the monitors ground cord. To use this clip from the 725 Wrist Strap Monitor using a small feature there must be an SCS 10 mm Female Snap screwdriver. The 725 Wrist Strap Monitor is now ready Fastener 3034, attached to the grounding layer of the to mount. Position the monitor so that it is convenient worksurface. Simply align the male snap on the monitor for the operator to plug their wrist strap ground cord into with the female snap on the worksurface and press the jack on the front of the monitor. It is recommended downward on the monitor. The worksurface is now that the front face of the monitor be flush or slightly automatically grounded through a one megohm resistor recessed from the front edge of the workbench. Attach by the 725 Wrist Strap Monitor. the monitor to the workbench with the screws. It may be necessary to pre-drill pilot holes for the screws. Use of an optional SCS Stand-By Jack 3057 at the Attach the dual conductor ground clip or each wire of work station extends the life of the monitors input jack. the monitors dual conductor ground cord to a suitable The user disconnects the wrist strap ground cord from ground. the wristband and plugs into the Stand-By Jack 3057 which is mounted at the work station. Plugging into Note: Use of the monitor in this way precludes the Stand-By Jack 3057 prevents the 725 Wrist Strap grounding a worksurface through the snap connector on Monitor from continuously alarming when disconnected the bottom of the monitor. A static control worksurface, if from the wristband. present, would require grounding separately through an additional ground cord. Note: Although the worksurface is grounded by the SCS 725 Wrist Strap Monitor, it is not monitoring the ground to the worksurface. Figure 3. Installating the 725 Wrist Strap Monitor underneath a workbench Figure 2. Using the 725 Wrist Strap Monitor with a worksurface SCS - 926 JR Industrial Drive, Sanford, NC 27332 East: (919) 718-0000 West: (909) 627-9634 Website: StaticControl.com 2017 DESCO INDUSTRIES, INC. TB-9014 Page 2 of 5 Employee Owned