810DX 9/9/2008 REV D
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button for 3 seconds. Turn Receiver OFF by pressing the ON/OFF DEPTH button for 3
seconds. Disconnect the accessories when you have finished your locate.
6.2.2 Determining the Depth of a Utility -
The depth of a utility may be determined in any of
the Transmitter hook-up modes. When determining depth in the Inductive Mode, move at
least 35 feet (12 m) from the Transmitter to prevent air coupling with the transmitter
signal. Signal strength must be greater than 250 for a depth estimation.
Keep in mind that any number of variables; including soil conditions, overhead lines,
adjacent utilities, and the utility material may affect depth measurements. Most water and
gas pipes are deeper than CATV and telephone cable. Use the depth measurement as a
verification that you are still on your target utility.
1
Position over the utility -
Stand facing along the length of the utility. See figure 6-5.
Confirm a centerline with the 810Dx Receiver.
2
The depth reading
- Hold the Receiver vertically over the centerline with the tip to
ground. Press and release the On/Off Depth arrow button. The depth in feet and inches
(or centimeters) is displayed for 3 seconds.
When determining depth, the Receiver Left/Right Guidance System must be centered
within 3 bars from the centerline in order to get a depth reading. If it is not, the unit will
beep and display “CL” (center line) when you press the On/Off Depth button.
If the signal strength is less than 250, the Receiver will display “FEr”. If the utility is
deeper than 20 ft. (600 cm) the Receiver will display only 20 ft. (610 cm).
Figure 6-5: Receiver Position When Determining Depth
6.2.4 Triangulating to Verify Depth -
If the depth of the utility suddenly changes to a much
different measurement, or a utility is buried in a common trench, triangulate to confirm depth. This
process will confirm the location and the depth of the target utility.
Triangulation is based on the principle that two sides of a 45-degree right triangle are equal. See
Figure 6-6.
Figure 6-6: Principle of Triangulation
Verifying Depth with Triangulation:
