3M 2250M 用户手册

 22 

78-8130-6150-0 Rev G

2.  Turn the transmitter on by pressing Ohms [T-2]. The continuity of the circuit will be 

measured. The results are displayed [T-4] in ohms and as a tone.

 

− If the continuity of the circuit is very good (the reading on the display is less 

than 3K Ω. and a solid tone from the transmitter is heard) all frequencies can 

be used to locate. Always use the lowest frequency available (for example, 577 

Hz). Lower frequencies are less likely to ‘bleed over’ to other cables in the same 

area, and are very good for tracing over long distances.

 

− If the circuit reads more than 3K Ω., but less than lOK Ω (indicated by a 

beeping tone from the transmitter) it will be necessary to use a higher frequency 

than 577 Hz in order to locate the cable/pipe.

 

− If the circuit reads more than lOK Ω., it will be necessary to use an RF signal 

such as 33 kHz or 200 kHz.

 

− If there is no tone and the transmitter indicates that there is an open circuit (OL 

in the display) this could be an indication of a poor ground, or an open-ended 

cable or pipe. Use one of the higher frequencies available, at high or maximum 

output power level. If it is an open-ended cable or pipe, the receiver's response 

will decrease suddenly at the site of the clear or severed end.

displaying ohms, the flag over the Ω symbol will be visible. When displaying volts, the 

rapid beeping tone will be heard.
3.  Press Trace [T-3] repeatedly until the desired frequency appears on the display.
4.  Press Output Level [T-5] to select high or maximum output power level for longer 

tracing distances or deep pipe/cable.