Fisher TW-7700 User's Manual
Contents
1. Digital Numeric Readout 0 99 amp Bar Graph Sensitivity Automatic LCD Backlight Included Battery Test Automatic Low Battery alert Push button readout Battery Six cells Battery Life 80 Hours Weight 5 4 Ibs Operating Temp 4 to 140 F 20 to 60 TRANSMITIER Output Frequency 82kHz Output Power nominal Watts Battery TeSt Yes Battery Two 6 Volt lantern batteries Battery Life 80 Hours Wei Qh tite eesti 5 0 Ibs Fisher Research Laboratory does not warrant suitability to specific use Fisher Research Laboratory shall in no event be liable for any direct incidental conse quential or indirect damages QUALITY Fisherdetectorsare renowned fortheir quality Each detectorishand crafted in the USA with pride PERFORMANCE Ourdetectorsand locatorsare durable dependable and search deeper REPUTATION Fisher produced the first patented metal detector in 1931 For over 70 years the Fisherlogo hasbeen a mark of excellence 2 YEAR WARRANTY Fisherbelievesin the products we produce backsthisbelief with a 2 yearlimited waranty Wa manty may vary outside the United States See2. 3 P 1 T 11 Operatng Manual FISHER RESEARCH LABORATORY Description pg Transmitter pg 4 gt 2 5 pg 7 Operating 8 Depth pg 9 SPECIFICATIONS 10 N The TW 7700 Digital Line Tracer consists of a transmitter receiver ground plate ground rod assembly canying case hard or soft an operators manual The TW 7700 isa single frequency line tracer The TW 7700 is an active locating line tracer There are three methods of active locating that an operator can use totracea utility The conductive method is the most preferred method since strong transmitter signal is transmitted through the intended target The inductive method is the easiest method to use but may not yield the best results When a direct connec tion is not available but the operator has good knowl edge of where one point of the utility may be the op erator can placethe Transmitter over the utility mak ing sure that the arrow on top of the tr
3. ansmitter is parallel tothe path of the utility Thethird method of active locating involves using the coupling clamp ac cessory The coupling clamp is used when theutility is exposed but a direct connection is not available The clamp jaws are opened and placed around the utility The clamp never makes a direct connection with the utility that is the utility can move freely with the clamp around it The features of the TW 7700 make it a very easy practical instrument in today s world of underground locating 00 Transmitter Located thetransmitter are the power mode and the accessory output The power mode enables the operator to turn the transmitter or off and to check the condition of the batteries When checking the batteries a reading if 50 or greater on the display meter indicates that batteries are usable Theaccessory output is for the ground plate ground rod assembly and for the coupling clamp Thereisa Red LED light that blinks when thetransmitter is on The batteries are located underneath a lid on top of thetransmitter housing WARNING Do not handle output leads unless power is off ELECTRIC SHOCK HAZARD Servicing to be performed by qualified personnel only The TW 7700 Transmitter Contols The TW 7700 Receiver Mode This button does not have a function on the TW 7700 It allows users of the TW 8800 Multi F requency Line Tracer to change frequencies Pow
4. er On Off Turns the receiver on or off Light Lights up the display for usage in dark areas When the display is backlit LIGHT is shown on the bottom hand side of the display screen Bat Press and hold this pad to check the battery level of the receiver A bar graph on the right side of the display will give status of the batteries When the graph shows 1 bar it is time to replace the batteries Additionally as the operator uses the Receiver if the batteries get low RE PLACE BATTERIES will appear in the lower area of the Display screen Vol up Vol down Increases or decreases the volume of the speaker Depth After determining the centerline of the utility set the blade of the receiver on the ground press and hold this pad to get the depth to the center of the target ee 5 TW 7700 RECEIVER OVER TARGET SIGNAL 82KHz 75 Display Frequency Modes The frequency at which the receiver is operating lt lt Left OverTarget gt Right gt gt Indicates where the receiver is in relation to utility Numeric Display Serves a dual function Relative signal strength of the transmitted signal shown Responds in conjunction with the bar graph Depth to the center of the target when DEPTH pad is pressed or CM shown Light Indicates the display is lit activated by pressing LIGHT BarGraph Serves three purposes e Responds in conjunction with signal strength i
5. itially disregard the LEFT RIGHT indicator and rely on the signal strength readout Make note of the high readings These are areas that need to be traced examined in more detail Tracing After locating the point s where the signal strength was the highest return to that those points and start tracing your utility This is where the LEFT RIGHT indicator is very helpful Swing the receiver from left to right and lis ten for the change of tone When the target is to the RIGHT of the receiver the tone is pulsed tone As the receiver gets closer to the target the pitch gets higher When the target is to the LEFT of the receiver the tone is a continu ous tone As the receiver gets close to the target the pitch also becomes higher When the receiver is over the target OVER TARGET is displayed on the display screen and the tone is at its highest peak sound Depth Measuring When an OVER TARGET response is displayed position the blade of the receiver directly over the utility and place the tip on the ground Hold the receiver steady press and hold the DEPTH pad Depth will be measured to the center of the utility Depth measurement isa feature of the TW 7700 Accuracy is defined on an ideal target thatis one that iscontinuous good conductor and not surrounding by other utilities There are factors that can cause the operatorto question the accuracy of the utility being traced A I
6. ndicator for battery test when BAT pad is pressed Volume loudness indicator when VOL up VOL down is pressed Replace Batteries When the receiver batteries fall below a nominal level REPLACE BATTERIES will be displayed No Signal When no signal is received by the receiver NO SIGNAL will display This response may be due to the transmitter not being turned on or the transmitter and receiver not be set at the same frequency ASS ESSO Ri Ea Coupling Clamp The coupling clamp is useful when the utility is exposed a direct connection is not possible It is plugged into the same plug in socket as the ground plate ground rod assembly The coupling clamp only operates at the 82 kHz frequency The coupling clamp will fit around utili ties that are 3 inches in diameter or smaller The length of the cable is approximately 10 feet Coupling Clamp Applications Diagram A The coupling clamp is for all tracing applications with con ductors exposed exception an open circuit atline stermination B A ground must be provided for the proper curent flow when the coupling clamp is used at a ter mination C The coupling clamp must be used between the grounding and where the line goes under D Trace signal will return to ground when incorrectly coupled E Signal will be transmitted in both directions when connect ing ismidway in a long conductor F Drop lines or laterals divide the signal stre
7. nductive Transmitter Setup Inductively only small portion of the signal attaches itself to the utility With a weakened signal trace should be accurate but depth may not The conductive method will yield better results Low Receiver Signal Strength When the signal strength falls below 20 25 depth readout may not be accurate It would be beneficial to move the transmitter to a closer point of contact Nearby Utlities Close nearby utilities may have some influence on the accuracy of the Depth readout This is more prone to happen in the higher frequencies where signals can jump to nearby utilities Switching to a lower frequency can give better results Moisture Ground that is too dry or overly saturated may skew the depth readout Ts elbows orsplits in the utility can distort the transmitted signal in thatgeneral area WARNING Do not connect output leadsto a live energized utility Please prevent shock hazard and equipment damage ASAIO NS Subject to improvement or modification without notice REC BVER Depth 1 inch foot in nominal condi tions Readout Inches or cm factory preset Left Right Guidance Audio continuous tone eft pulsed tone Right VCO varying pitch output for easy over target location Visual Left Right Over Target messages Signal Strength
8. ngth in half at each junction ground This represents a jumper Headsets Fisher Research Laboratory has a variety of headsets avail able eUlItra quiet deluxe Fisher Phones High quality sound while reducing the outside noise Standard Stereo Headphones Single Earpiece Headset Enables the operator to effec tively listen to the TW 7700 and remain aware of noise close proximity ee 7 See The following instructionsare designed fora safe and effective method of line tracing and utility avoidance Some of the steps may not be applicable allsituations The undenying guideline is that operator safety must be maintained at all times Use of safety equipment extra personnel and up to date as built plans should be considered when necessary INTALSC AN Set up Transmitter either Inductively or Conductively Inductive Be aware of air coupling the transmitted signal travelling to the Receiver via the air not the utility Conductive Connect the ground plate ground rod assembly to the trans mitter Connect the red lead tothe energized utility Con nect the black lead to the ground plate ground rod Place the plate rod at a 90 degree angle in reference to the utility Be sure not toplacethe wires over any other utility After transmitter set up move away from the point of con nection or Induction about 25 feet 8 meters Sweep a circle around the point of connection In
9. yourdealerfordetails SERVICE Fisher iscommitted to providing you ourvalued customer with supenorservice Each and every instrument is rigidly tested and carefully insoected during assembly and before shipment Should you have any questions orproblems contact FISHER RESEARC H LABORATORY 200 W Willmott Rd Los Banos 93635 Tel 209 826 3292 Fax 209 826 0416 www fisherab com email info fishernab com EXPORT DEPARTMENT P O Box 1896 New Haven CT 06508 USA Tel 203 288 1638 Fax 203 287 8099 FRL 8708002 A email mb exportdept com
Download Pdf Manuals
Related Search