3M CTM051 User Manual page 10

Using Reference with Voltage
Measurements
Using Reference with
Impedance Measurements
The Reference function
helps to set limits at which
an audio alarm sounds to
indicate that the measured
impedance is below the
specified limit. Unlike a
regular multimeter, the 3M
Ground Pro Ground Integrity
Meter allows you to specify
an exact impedance value
at which the instrument will
provide an audio indication.
In Impedance mode, depress
the Ref. button. You should
see a screen similar to the
one on the right with the REF indicator on. The top line of the display
shows the current impedance value (in this example it is an open circuit)
and the bottom line shows the reference level. Adjust the reference level by
using the Up and Down arrow buttons. Now when the impedance is below
the reference value, you should hear a beep. The reference value is set for
a particular range - you may need to readjust it for a different range. The
reference value will be saved in the internal non-volatile memory.
9
0 2
™
REF
O hm s
R ef
4 6 8 10
4 6 8 10
Normal
measurements
screen
Impedance
in Ohms
Threshold