78-9000-5020-0 Rev C
35
9. Locating Frequencies
A. Active Frequencies
Active frequencies are trace signals supplied by a 3M
™
Dynatel
™
Transmitter 7500 Series
(577 Hz, 1 kHz, 8 kHz, 33 kHz, 82 kHz or 133 kHz /200 kHz).
•
Select the same frequency that the transmitter is generating.
•
Press
Menu/
OK [6] (you may have to press
Menu
twice to toggle to the LOCATE
MENU display).
•
Press
Cable/Pipe
[SK]
•
Press
Freq
[SK]
•
Press
Active
[SK Toggle] until the desired frequency is displayed: (“Active” 577, 1k,
8k, 33k, 82k or 133k/200 kHz)
•
Press
Menu/
OK [6] to return to Locate mode.
B. Power Frequencies
7550/7573 Locator
Power frequencies refer to 50 or 60 Hz signals, and their harmonics, that can be traced
without the use of a transmitter.
60:
Best for general locating of passive power.
60H (high harmonic):
If the 60 choice appears to be responding slowly, or poorly, then
60H is the second choice for locating passive power.
60L (low harmonic):
Third choice for passive power locating. May be used when 60 or
50H is weak or erratic.
7550E/7573E Locator
50:
Best for general locating of passive power.
50H
(high harmonic): If the 50 choice appears to be responding slowly, or poorly, then
50H is the second choice for locating passive power.
50L (low harmonic):
Third choice for passive power locating. May be used when 60 or
60H is weak or erratic.
100 Hz:
Used for locating rectified AC power signals, often found on pipelines using
impressed current cathodic protection.
120 Hz:
Used for locating rectified AC power signals, often found on pipelines using
impressed current cathodic protection.
•
Press
Menu/
OK [6] (you may have to press
Menu
twice to toggle to the LOCATE
MENU screen).
•
Press
Cable/Pipe
[SK].
•
Press
Freq
[SK].
•
Press
Power
[SK Toggle] until the desired frequency is displayed: (“Power” 60, 60L,
60H, or 120).
•
Press
Menu/
OK [5] to return to Locate mode.
All U.S. receivers default to 60 Hz.