3M CTM051 User manual

3M™Ground Pro
Ground Integrity Meter
Model CTM051
User’s Guide

1
3M™Ground Pro Ground Integrity Meter
Model CTM051
Safety Information
Read, understand, and follow all safety information contained in these user
instructions prior to use of the 3M Ground Pro Ground Integrity Meter Model
CTM051. Retain these user instructions for future reference.
EXPLANATION OF SIGNAL WORD CONSEQUENCES
WARNING: Indicates a potentially hazardous situation, which, if not avoided, could result in
death or serious injury and/or property damage.
CAUTION: Indicates a potentially hazardous situation, which, if not avoided, may result in
minor or moderate injury and/or property damage.
NOTICE: Indicates a potentially hazardous situation, which, if not avoided, may result in
property damage.

2
 WARNING
To reduce the risks associated with environmental contamination:
When working with the automated equipment, always observe safety precautions as•
recommended by equipment manufacturer and your company’s practices
 CAUTION
To reduce the risks associated with environmental contamination:
Dispose of the monitor in accordance with local, state, and federal regulations•
NOTICE
To reduce the risks associated with property damage:
Periodically check that the indicator is functioning properly•
FCC
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two
conditions: (1) this device may not cause harmful interference, and (2) this device must accept any
interference received, including interference that may cause undesired operation.
Note: This equipment has been tested and found to comply with the limits for a Class A digital device,
pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection
against harmful interference when the equipment is operated in a commercial environment. This
equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in
accordance with the instruction manual, may cause harmful interference to radio communications.
Operation of this equipment in a residential area is likely to cause harmful interference in which case
the user will be required to correct the interference at his own expense.
Industry Canada
This Class A digital apparatus complies with Canadian ICES-003.

3
The 3M™Ground Pro Ground Integrity Meter is a comprehensive instrument that
measures the ground connection of your equipment in accordance with ANSI 6.1 and
ANSI/ESDA S.20.20 standards. In addition to measuring ground impedance, it also
measures AC and DC voltage on the ground as well as the presence of high-frequency
noise or electromagnetic interference (EMI) on the ground, alerting you to possible
functionality problems, such as tool lockups, erratic behavior and parametric errors.
Controls and Indicators
Turns the power on and off. Hold for a few seconds to turn the unit off. Also
resets some parameters.
Switches the unit into impedance measurement mode.
Switches the unit into high-frequency noise (EMI) measurement mode.
Switches the unit into AC and DC voltage measurement mode.
Sets up the reference for measurements and alarms.
Freezes the display/and shows the maximum measured value.
Adjusts the scale for some parameters and adjusts reference values.
Display backlight on/off
EMI
Ref.
V
P owe r
C
Ohms
Hold

4
Brief Tour of your 3M™Ground Pro
Ground Integrity Meter
Please refer to the rest of this User’s Guide for detailed explanations of each control,
indicator and connection.
Display
Banana Jacks
Keypad
Battery Compartment
(on the back)

5
Overview
The 3M™Ground Pro™Ground Integrity Meter measures several important
parameters of ground integrity: ground impedance, voltage, and high-frequency noise
(EMI) on a ground.
Ground connectivity is measured in accordance with ANSI 6.1, ANSI/ESDA S.20.20
and other standards. More specifically, it is measured as AC impedance in a way that
is immune to parasitic voltages and currents on a ground.
In addition to monitoring the ground connection, the Ground Pro measures high-
frequency voltage (EMI) on the ground that is often present in a factory environment.
Such interference causes problems with the operation of equipment.
The Ground Pro also measures AC and DC voltage on the ground in case of
miswiring.
General
Power
Ground Pro uses a 9V alkaline battery. Do not use any other battery. If you are not
using your Ground Pro for an extended period of time, remove the battery from the
unit in order to prevent damage caused by a possible battery leakage.
Note: Not all batteries labeled similarly have the same performance. Often an off-
brand alkaline battery has only 50% to 60% of the capacity of the leading brand-name
battery.
Installing the Battery
Slide off the battery door at the back of the Ground Pro and attach the 9V battery to
the battery clips. Observe the polarity of the battery. Re-install the battery door.

6
Low-Battery Indicator
When battery voltage gets low (less than 20% capacity
remains), the low battery indicator on the display
appears. At this point it is a good idea to install a new
battery to assure optimal performance.
Turning Unit On and Off
ON
Press the Power/C button. The battery voltage will be displayed for a
moment in both volts and percentage of the full capacity. If the battery voltage is too
low even to indicate low-voltage status on the display or if the self-diagnostic fails, you
will hear a beep and the unit will shut itself off. If the battery is completely “dead,”
there may not even be a beep. Please replace the battery.
OFF
Press the Power/C button for at least two seconds. The 3M™Ground Pro
Ground Integrity Meter will turn off.
Automatic Power Off
In order to save battery life, the Ground Pro has an
automatic power-off (APO) feature that will turn off the
Ground Pro off after approximately 10 minutes if no
buttons are pressed. You can disable or enable APO by
depressing the F button several times until you get to the screen shown to the right.
You can then enable or disable APO using the Up and Down arrow buttons. Please
keep in mind that with APO disabled, the battery life will be shorter.
Checking the Battery Voltage
Press the F button several times until you get to the
following screen. The upper display shows the battery
voltage, and the lower display shows the percentage of
usable battery life left.
Low-Battery Indication
0 62 4
P owe r
C
F
%
V
Lin
0 62 4
F

7
Impedance Measurements
Depress the Ohms button to go into ground impedance
mode. You should see a screen similar to the one
shown on the right. The impedance mode is indicated
by “OH” on the bottom display line.
Scaling
The 3M™Ground Pro Ground Integrity Meter has
four different scales for measuring ground impedance. Choose the appropriate scale
for your measurements using the Up and Down arrow buttons.
Auto-Zeroing Test Leads
Test leads offer added impedance and may alter
measurement results, especially at a lower scale. In
order to take impedance of test leads into account,
short the ends of the test leads together and depress the
Function button (F) until you see the screen shown on
the right. In a few seconds, this screen will disappear
and you will hear a short beep. The Ground Pro will
return to normal measurement mode. Now when the
test leads are shorted together, the display should show
zero Ohms, even though the test leads may have some
impedance. The correction factor will be saved in non-
volatile memory.
X.XX Ohms XX.X OhmsX.XXX Ohms XXXOhms
O hms
0 6 82 4
Ohms
0 62 4
F
Impedance Screen
0 2 4

8
Voltage Measurements
The presence of voltage on a ground is never desirable.
The 3M™Ground Pro Ground Integrity Meter can measure
both AC and DC voltages on a ground.
AC Voltage
Press the V button once. The Ground Pro
will switch to AC voltage measurement
mode and you should see a screen similar
to one on the right. You can adjust the
measurement scale using the Up and Down
arrow buttons.
DC Voltage
Press the V button again to switch to DC
voltage measurement mode. You should see a
screen similar to the one on the right. As in AC
mode, you can adjust the measurement scale
using the Up and Down arrow buttons.
Overload
If voltage on the ground is above the maximum
level on a particular scale, you should see an
overload indicator such as the one on the right.
In such a case, go to the next scale using the Up
arrow button.
V
V
0 2 4
V
0 2 4
0106 82 4
If the test leads are not shorted properly or become accidentally disconnected
during this process, auto-zero will fail and you should hear a long beep before the
display returns to the impedance measurement screen. In this case you will need
to repeat this process again.

9
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.
Ohms
Ref
Normal
measurements
screen
0106824
Threshold
Impedance
in Ohms
10684
REF