3M Workstation Monitor 724 - Allied Electronics

Audible Alarm TonesFor wrist strap malfunctions the 3M Workstation Monitor 724 indicates a differenttone for each operator – a continuous tone for#1 operator and a fast chirping beep for #2operator. The volume of the wrist strap alarmis adjusted by selection of the internal DIPswitch #1. For work surface malfunctions, aslow chirping beep is made. This alarm soundis turned on or off by selection of DIP switch#2. Switch #1 and #2 are accessible through aslot located in the bottom of the chassis.LoudOnDIP switchOffSwitch #1Switch #2Soft3M Workstation Monitor 724 bottom viewFigure 4 – Selected desired alarm optionsModel 724 bottom viewWork Surface MonitoringThe Workstation Monitor 724 monitors its connection NOTICEto ground and the grounding of a 3M ESD worksurface. A loop resistance is measured from theThe grounding wire from themonitor, through a 3M Monitor/Table Mat Cordwork surface and the groundwire from the 3M Workstation2380D to the work surface (Section 2), across theMonitor 724 must be attached toconductive layer of the work surface, through theseparate electrical grounds. Thegrounding wire of the work surface to an electricalwork surface monitoring functionground and finally back to the monitor through theis active any time that the powerWorkstation Monitor 724 grounding wire. If thesupply for the monitor is plugged in.resistance of the loop exceeds 3.7 Megohms the worksurface high red lamp (M) will illuminate and allgreen lamps will be extinguished. If DIP switchNOTICE#2 is in the ON position (Figure 4) the audiblealarm will activate. If no ESD work surface is to beDisconnect the 3M Monitor/monitored, the Monitor/Table Mat Cord 2380D andTable Mat Cord 2380D to preventthe ground wire of the Workstation Monitor 724possible damage to the 3M must be connected to an electrical ground (SectionWorkstation Monitor 724 before3). This is done to ensure that the Workstationtesting the resistance of theMonitor 724 is providing a ground connection forwork surface with a high voltagethe operators. Again, if the loop resistance exceedsmegohmmeter.3.7 Megohms the work surface high red lamp(M) will illuminate and the alarm will activateif selected. 2380 Mat Cord (without resistor) can also be used with the 724Workstation Monitor It can be used when the surface resistance threshold of 3.7Megohms is reached using the 2380D.9

SECTION 2Installation of 3M Workstation Monitor 724 with Work SurfaceGround MonitoringWire Attachments and Grounding - See Figure 12 for complete drawing of theWorkstation 724 wire connections.Tools required – Small blade, screwdriver and wire cutter.a)Connect the work surface to an electricalground with the appropriate one megohmground cord you received at time of purchase.b) Using a small screwdriver move the DIPswitch #2 on the Workstation Monitor 724to the ON position to activate the worksurface audible alarm (Figure 4).c)Locate the accessory package that containsa 3M Monitor/Table Mat Cord 2380D,Workstation Monitor 724 ground wire (withring terminal), and the two-wire connectorplug.d) Attach the 3M Monitor/Table Mat Cord2380D (tinned wire end) to the work surfaceterminal of the two-wire connector byinserting it into opening and securing withthe screwdriver (Figure 5A or 5B). Attachthe plastic cap end to the snap on the worksurface.Note: Two snap fasteners orappropriate connectors must beinstalled at opposite corners of thework surface to use this feature.For recommended surfaces to usewith the 3M Workstation Monitor724 please refer to Section 14. Useof a 3M Female Snap Fastener3034 or 3050 (depending on thetype of surface) is recommendedfor connection to the 3M Monitor/Table Mat Cord 2380D that issupplied with the WorkstationMonitor 724. If you are using the3M Dissipative Hard LaminateMaterial 8300, attach the Monitor/Table Mat Cord 2380D to suitablehardware used to make an electricalconnection to the ground layer of thework surface. This may require youto cut off the plastic cap end of theMonitor/Table Mat Cord 2380D.Note: If for any reason a snap fastenercannot be used on the work surface,the plastic cap on the end of the 3M Monitor/Table Mat Cord 2380D canbe cut off and replaced with a ringterminal not supplied (Figure 6).e)Determine how you want to ground theWorkstation Monitor 724: If you are grounding through the ACadapter perform step (2f). If you are grounding through theWorkstation Monitor 724 ground wire perform step (2g).f)Attach the tinned ground wire of the AC adapter to the ground terminal of thetwo-wire connector by inserting it into opening and securing with screwdriver(Figure 5B). Continue with step (2h).g) Attach the tinned Workstation Monitor 724 ground wire to the ground terminalof the two-wire connector by inserting the tinned end into openingand securing with screwdriver (Figure 5A). Attach the ring terminal end with ascrew (not supplied) to an electrical ground (Figure 7B). Continue with step (2h).10

h) Plug the two wire connector into thejack at the rear of the 3M WorkstationMonitor 724 (Figure 8).i)Insert the plug connector of the 3M Dual Conductor Remote Input Jack 732cable into the 732 jack at the rear of theWorkstation Monitor 724 (Figure 9).j)Insert the round connector from the ACadapter into the jack at the rear of theWorkstation Monitor 724.Note: Disconnect the 3M Monitor/Table Mat Cord 2380D to check forvisual and audible high work surfacealarm condition and reconnect. Ifthe high work surface lamp (M) is onbefore removing the Monitor/TableMat Cord 2380D, check for looseconnections or high resistance toground ( 3.7 Megohms). Disconnectthe Monitor/Table Mat Cord 2380Dfrom the work surface and check theresistance to ground by attaching onelead of an ohmmeter to the connectoron the work surface and the other leadto ground.SECTION 3Installation of 3M Workstation Monitor 724 without Work SurfaceGround MonitoringWire Attachments and Grounding – See Figure 12 for complete drawing ofWorkstation Monitor 724 wire connections.Tools required – Small blade, screwdriver, and wire cutter.a)Using a screwdriver move DIP switch #2on the Workstation Monitor 724 to the OFFposition to deactivate the work surfaceaudible alarm (Figure 4).b) Locate the accessory package that containsa 3M Monitor/Table Mat Cord 2380D,Workstation Monitor 724 ground wire (withring terminal), and the two-wire connectorplug.c)Attach the Monitor/Table Mat Cord 2380D(tinned wire end) to the work surfaceterminal of the two-wire connector plugby inserting into opening and securingwith screwdriver (Figure 5A or 5B).11NOTICEDo not physically connect the 3M Monitor/Table Mat Cord 2380Dand the 3M Workstation Monitor724 ground wire together. Theground wire for the work surfaceand the ground wire from theWorkstation Monitor 724 mustbe attached to separate electricalgrounds. However, by attachingthe wires to the same ground butat a different physical location,the Workstation Monitor 724 cancheck for loose or lost connectionsto ground. This would be indicatedby the high red work surface lamp(M) illuminating.

d) Cut off the plastic cap on the end of the 3M Monitor/Table Mat Cord2380D and strip off approximately 1/2 inch of insulation and twist thestranded wire together (Figure 6). Attach this end to an electrical groundusing a ring terminal (not supplied) or by wrapping the wire around thehead of a screw (Figure 7A).e)Determine how you want to ground the 3M Workstation Monitor 724: If you are grounding through the AC adapter, perform Step (3f.) If you are grounding through the Workstation Monitor 724 ground .wire, perform Step (3g.)f)Attach the tinned ground wire of the AC adapter to the ground terminalof the two-wire connector by inserting into opening and securing withscrewdriver (Figure 5B). Continue with Step (3h.)g) Attach the tinned Workstation Monitor 724 ground wire to the groundterminal of the two- wire connector by inserting the tinned end into openingand securing with screwdriver (Figure 5A). Attach the ring terminal endwith a screw (not supplied) to an electrical ground (Figure 7B). Continuewith Step (3h.)h) Plug the two wire connector into the jack at the rear of the WorkstationMonitor 724 monitor (Figure 8).Two-Wire Connector3M Monitor-Table MatReplacement Cordwith DiodeAC AdapterGround WireAttach 3M Workstation Monitor724 Ground Cord or ACAdapter Ground Wire2380D3M Monitor-Table MatReplacement Cordwith DiodeDC Plug3M Workstation Monitor724 Ground CordAC AdapterFig. 5AFig. 5BFigure 5A & 5B – Attaching ground wire/cord and work surface cord to two-wire connector.12

Figure 6 – Cutting off table mat ground snap.Figure 7A – Attaching system grounds. Note work,surface and unit are grounded at different locations.Figure 7B – Grounding 3M Workstation Monitor724.Figure 8 – Inserting two-wire connector into rear of3M Workstation Monitor 724.Figure 9 – Inserting 3M Dual Conductor RemoteInput Jack plug into rear of 3M Workstation Monitor724.13

SECTION 4Selection of Test Voltage and Resistance LimitTools required – Small blade, screwdriver.The 3M Workstation Monitor 724 allows for the selection of test voltages (9Vor 16V) and resistance limits (10 Megohms or 35 Megohms). The additionalranges have been added to accommodate global ESD requirements. Selection ofthe operating parameters are left up to the user’s discretion.a)Select the desired resistance and voltage limit by moving the appropriateslide switch (with screwdriver) on the side of the Workstation Monitor 724to the desired position (Figure 2).SECTION 5Mounting the 3M Workstation Monitor 724 and3M Dual Conductor Remote Input Jack 732a)Mount or position the WorkstationMonitor 724 so that the lampsare easily viewed by the operator(Figs. 10 and 11). Mount theWorkstation Monitor 724 to theunderside of a work bench topor shelf through the two holeslocated at the top rear of the caseusing the two screws supplied. Ifusing the screws is not possible,apply an appropriate amount ofdurable, double-sided adhesivefoam tape to the case.Figure 10 – 3M Workstation Monitor 724mounted on bench top.b) Locate the Dual ConductorRemote Input Jack 732 so thatit is convenient for the operatorsto attach their wrist strap groundcord. Mount the remote with thescrews provided.Figure 11 – 3M Workstation Monitor 724mounted under shelf or bench.14

c)Plug the AC adapter intoa 3-prong grounded outlet(North American System).Outside North America useappropriate AC adapter (seespecifications Section 11). The3M Workstation Monitor724 is ready for use.3M Workstation Monitor 724Rear3M WorkstationMonitor Remote 724GroundGroundConductiveWork SurfaceWhen not using workstation monitoringfeature, connectwork surface wireto ground.Attach a 3M Dual ConductorGround Cord to a 3M DualConductor Wrist Band. Plug the cordinto either of the two jacks on the3M Dual Conductor Remote InputJack 732 (Figure 13). Plugging intoa jack activates the monitor for thatinput.b) The high wrist strap red lamp(H) should illuminate and thecorresponding audible alarm forthe input (1 or 2) should soundindicating proper functioning ofthe monitor.c)GroundFigure 12 – 3M Workstation Monitor 724 wireconnection diagram for single work station.SECTION 6Wrist Strap Connectiona)AC AdapterFigure 13 – Connecting wrist snap ground cord to3M Dual Conductor Remote Input Jack 732.Slip the wrist band on your wrist.The alarm should quiet and thewrist strap high red lamp (H)should slowly extinguish. Thecorresponding OK wrist strap greenlamp (1 or 2) should illuminate.15

SECTION 7Fault Conditions(Refer to Figure 3)Red Wrist Strap Lamp (H) Accompanied by an Audible AlarmThis indicates that a high resistance condition(greater than 10 Megohms or 35 Megohms)exists for an operator or wrist strap assembly.If two operators are connected to the monitorthe high condition is with the operatorwhose green lamp has extinguished. Checkthe operator for good contact between thewrist and band. Check the ground cord andconnections for continuity. Some operatorshave difficulty in providing sufficientcontinuity to the wrist band due to dry skin orarm hair. They may need to use an approvedskin moisturizer or reposition the wrist bandon the arm.Note: The operators may complain thatthe alarm is sounding too often untilthey learn to adjust the wrist band tofit securely or apply an approved skinmoisturizer on a frequent basis. Pleaseremember that the monitor is informingyou that the operator is exceeding theestablished static control requirementfor resistance to ground when wearinga static protective wrist strap assembly.These alarms alert the operator whensensitive electronics are possibly beingexposed to static electricity. Prior toincorporating the work station monitorinto your static control process, theoperator was unaware of these events.Yellow Wrist Strap Lamp (L) with no Audible AlarmNOTICEThis indicates that a low resistance condition (less than 1.5 Megohms) existsbetween the operator and ground. One or both of the one megohm currentlimiting resistors are being bypassed. A low resistance condition can becaused by touching a grounded object or by standing on a conductive surface.Red Work Surface Lamp (M)This indicates that a high resistance condition ( 3.7 Megohms) exists across theconductive layer of the work surface and/or the ground connections. Check thework surface, ground cords, and the connections for continuity. Note the audiblealarm may also sound if selected.16

SECTION 83M Standby Jack 3057Since the activating switches are located in the 3M Dual Conductor RemoteInput Jack 732 and 733, the normal operating procedure is for the operatorsto disconnect their cords from the remotes when leaving the work station.However, an optional Standby Jack 3057 that allows the wrist strap groundcord to remain plugged into the remotes is available. Simply attach it to anyconvenient location then disconnect the cord from the wrist band and attach it tothe standby jack. The OK green lamp (1 or 2) on the 3M Workstation Monitor724 will illuminate upon connection. The low yellow lamp (L) will slowly flashif the standby jack is grounded. It can be grounded by attaching a ground wireto the screws or back plate. It can also be grounded if the plate is attached to agrounded metal surface. The operator should reconnect the wrist strap groundcord to their wrist band upon returning to the work station.SECTION 93M Dual Conductor Remote Input Jack 733The 3M Dual Conductor Remote Input Jack 733 is used to separate the twowrist strap jacks on the Dual Conductor Remote Input Jack 732 that connect to aWorkstation Monitor 724. This provides a separation up to approximately 10 feetapart. This is done using a second remote input module Dual Conductor RemoteInput Jack 733 in conjunction with the Dual Conductor Remote Input Jack732 originally supplied with the Workstation Monitor 724. Two separate workstations can also be created using the Dual Conductor Remote Input Jack 733and the 3M Monitor/Table Mat Interconnect Cord 2389 (10 ft.). Instructionsfor creating two separate work stations are included with the purchase of the 3MMonitor/Table Mat Interconnect Cord 2389 (Figure 15).17

SECTION 10Installation of 3M Dual Conductor Remote Input Jack 733a)Insert the plug connector of the DualConductor Remote Input Jack 733cable into the 733 jack at the rear ofthe 3M Workstation Monitor 724(Figure 14).b) Fully insert the small plastic plugthat comes with the kit into the#2 wrist strap input on the DualConductor Remote Input Jack Mdel732. This disables the #2 input andprevents a situation where two userswould simultaneously attempt to usethe input lines to the WorkstationMonitor 724.c)Figure 14 – Inserting 3M Dual ConductorRemote Input Jack 733 plug into rear of 3M Workstation Monitor 724Position and mount both remote input jacks in convenient locations.SECTION 11Verification Procedure for the Workstation Monitor 724The Workstation Monitor 724 cannot be recalibrated after the initial factorycalibration. However, the following steps can be used to determine if theWorkstation Monitor 724 is operating within its specifications.Equipment Needed: Small blade screwdriver. Resistance Substitution Box (RSB), 1 Ohm to 45 Megohms 1%. One two-conductor cable with standard 3.5 mm (miniature) phone plugattached on one end and appropriate connectors on the other end toconnect to RSB.Note: Two-conductor cable must have an isolation resistance of 1 Gigohmbetween conductors. Two separated wires may also be used to obtain higher isolation resistance. Two wires with alligator clips. Ohmmeter capable of measuring to 45 Megohms 0.5%, to verify the RSB.18

ProcedureWork Surfacea)Access the dual inline package (DIP) switches SW1 and SW2 through a slotlocated at the bottom of the chassis. Adjust SW1 to the LOUD position andSW2 to the ON position with a small screwdriver (Figure 4).b) Plug in the AC adapter. Note that the red high work surface lamp (M) isilluminated with an audible alarm (slow chirping beep).c)Adjust DIP switch SW1 to the SOFT position. Note that the loudness of thealarm decreases.d) Adjust DIP switch SW2 to the OFF position. Note that the audible alarm issilenced.e)Attach the 3M Monitor/Table Mat Cord 2380D and the 3M WorkstationMonitor 724 ground wire to the RSB using the two wires with alligatorclips. Set the resistance as follows and observe Workstation Monitor 724output:3.1 Megohms – Red work surface lamp (M) OFF.4.3 Megohms – Red work surface lamp (M) ON.f) Disconnect the cords from the RSB.g) Connect the ring terminal end of the Workstation Monitor 724 ground wire tothe metal snap of the Monitor/Table Mat Cord 2380D. The red work surfacelamp (M) should now be OFF.3M Workstation Monitor 724Attach 3M WorkstationMonitor 724 GroundCord or AC AdapterGround WireRearWorkstation Monitor724 Ground CordGround3M Monitor Table Mat CordAC AdapterAC AdapterGround Wire3M DualRemote SplitterConductive/DissipativeWork Surface #13M RemoteInput Jack3M Monitor Table Mat Cord Conductive/DissipativeWork Surface #2Work SurfaceGround CordGroundFigure 15 – 3M Workstation Monitor 724 wire connection diagram for two work stations. 19

Wrist StrapSet Resistance Limit 10 Megohms and Test Voltage 9V (Figure 2).h) Connect the two-wire cable with 3.5 mm phone plug into the #1 input ofthe 3M Dual Conductor Remote Input Jack 732 and attach the other endto the RSB. Set the resistance as follows and observe the 3M WorkstationMonitor 724 output:1.3 Megohms – Yellow low lamp (L) flashing, green (OK) lamp (1) ON,and audible alarm OFF.1.7 Megohms - Yellow low lamp (L) OFF, green (OK) lamp (1) ON, andaudible alarm OFF.8.5 Megohms – High red wrist strap lamp (H) OFF, green (OK) lamp (1)ON, and audible alarm OFF.11.5 Megohms – High red wrist strap lamp (H) ON, audible alarm ON(continuous tone), and green (OK) lamp (1) OFF.i)Repeat step (6h) for input #2 of the Dual Conductor Remote Input Jack 732.Audible alarm will be a fast chirping beep.Set Resistance Limit 35 Megohms

6 3M Dual Conductor Remote Input Jack 733 (optional) Figure 1 – 3M Workstation Monitor 724 with remote input jacks. 3M Dual Conductor Remote Input Jack 732 3M Workstation Monitor 724 SECTION 1 Theory of Operation The 3M Workstation Monitor 724 (Figure 1) is designed to monitor the operati