Checkline CTM User Manual
5.5 Non-linearity
Most three-point tension meters employ only linear characterization and
have large errors at the midpoints (up to 15%). The CTM uses multi-point
segmenting to correct for non-linearity, reducing it to less than 0.2%.
Table of Contents
1.0 Introduction .........................................................................................................................3
5.6 Wire Characteristics
6.0 T roubleshooting
Creep Every material including steel exhibits creep under load. It will
neck down over time, quite quickly over the fi rst few seconds
and much slower as time progresses. A wire cable also sees
creep from the wire spacing and wind. This effect is seen as a
display that drifts lower after it has been clamped in line.
Variations Material that varies in diameter or shape will have different
output at the same tension
Strands The best cable assembly is one that is perfectly round, as
it will not change contact geometry with the wire twist. The
closer the wire cable cross section appears to be round, the
better the measurement performance will be.
Problem Possible Cause Solution
Powers on momentarily and turns off
Does not power on Low battery Replace with high quality alka-
Display is
completely dark
Display drifts downward once installed
Temperature not
accurate
Low battery Replace with high quality alka-
line batteries
line batteries
Batteries installed
backwards or no
spring contact
Software reset Remove battery cap & reinstall
Display contrast too
light
Display contrast too
dark
Wire material is
creeping and internal friction between
wires is relieved.
Instrument changed
temperature environments
Instrument exposed
to sun
Insure that positive terminals
of both batteries (nub) face inward – towards the black cap.
Check that spring is attached
to the battery cap.
after one minute. Attempt to
turn power on again.
Hold the Right Arrow key down
while pressing the F2 key
several times to increase the
display contrast. If nothing occurs, release both keys. Press
the power button and try again.
Hold the Arrow key down while
pressing the F1 key several
times to decrease the display
contrast.
This is normal behavior of
wire. Lower display resolution
to mask this effect.
Allow instrument to remain in
environment until temp stabilizes or enter temp manually
Enter temp manually
1.1 Unpacking ...................................................................................................................3
1.2 Description ..................................................................................................................3
1.3 Important features .......................................................................................................4
2.0 Operation 5
2.1 Typical Operation ........................................................................................................5
2.2 Measurement Practices ..............................................................................................6
2.3 Softkey Functions .......................................................................................................7
3.0 Confi guration Mode ............................................................................................................11
3.1 Accessing the Confi guration Mode ...........................................................................11
4.0 Changing Sheaves .............................................................................................................14
5.0 Achieving Best Accuracy ....................................................................................................15
5.1 Accuracy ...................................................................................................................15
5.2 Calibration to Specifi c Wire Type ...............................................................................15
5.3 Loading Error ............................................................................................................15
5.4 Non-repeatability .......................................................................................................15
5.5 Non-linearity ..............................................................................................................16
5.6 Wire Characteristics ..................................................................................................16
6.0 Troubleshooting ..................................................................................................................16
16
1
Specifi cations
Power
2 AA, common alkaline batteries. Operational battery life over 40 hours at
room temperature. Battery life is reduced at lower temperatures.
5.0 Achieving Best Accuracy
The CTM is an instrument designed to give accuracy that typically exceeds
5.1 Accuracy
normal requirements for wire tensioning. You should have an understanding
of what factors affect tension measurement accuracy.
Display
Operational keys
Operational annunciators
Temperature detection
Display resolution
Dot graphic LCD display
Power, Wire, Escape/Clear (Esc), Next ( ) and four softkeys with changing fuction and label, depending on the specifi c menu in use
Unit of measure, battery level
Temperature accuracy approximately ±2° F (±1°C)
2,000 lbf/ 1,000 kgf/ 10,000 N CTM instrument:
Displayed resolution setting
Low Med High
lbf (pound-force) 10 lbf 5 lbf 2 lbf
kgf (kilogram-force) 5 kgf 2 kgf 1 kgf
N (Newton) 50 N 20 N 10 N
Custom units between 101 &
200 divisions
8,000 lbf/ 3,500 kgf/ 35,000 N CTM instrument:
Displayed resolution setting
Low Med High
lbf (pound-force) 50 lbf 20 lbf 10 lbf
kgf (kilogram-force) 20 kgf 10 kgf 5 kgf
N (Newton) 200 N 100 N 50 N
Custom units between 101 &
200 divisions
between 201 &
500 divisions
between 201 &
500 divisions
between 501 &
1000 divisions
between 501 &
1000 divisions
5.2 Calibration to
Specifi c Wire Type
Contact your distributor for any
additional calibrations you may
need.
While it is best to have the instrument calibrated to the specifi c wire size(s)
and type(s) used, the CTM can often work adequately in other situations. If
the best tension accuracy is required, it is recommended that a calibration
be performed for that specifi c wire size and type.
What calibration choice and sheaves should I use?
Situation
Exact wire size
and type is
shown in wire list
Wire size is
same, but type is
not identical
Wire size is not
the same
Do not use the CTM to measure tension for wires if both of the following are
true:
1. No wire calibrations are stored of the same diameter as the wire you are
looking to measure, and
2. You do not have sheaves of the same diameter.
If both of these conditions exist, contact your distributor.
Wire calibration
selection
Description of
exact match
Description of
same wire
diameter
Closest diameter
Sheave
selection
Sheaves noted
in list
Sheaves noted
for that wire size
Sheaves match-
ing the wire size
being measured
Accuracy
Best
Good
Fair
Available options
Operating environment
Dimensions
Weight
For ease of use, the display always counts by a multiple of 1, 2 or 5.
Varied wire sizes
Suitable for outdoor use
10˝ x 23˝ x 3˝ (25 cm x 59 cm x 8 cm) approximately
11 lb (5 kg) approximately
2
5.3 Loading Error
5.4 Non-repeatability
Contact your distributor to improve accuracy for a specifi c wire type by
calibrating to it.
A tensiometer works by defl ecting the cable, which makes the cable path
longer than when a tensiometer is not installed. When the tensiometer is
removed, the wire tension decreases as the cable length is restored. This
effect is known as loading error. The CTM design elongates the cable by a
mere 0.08 inch (2 mm), making loading errors extremely small.
The CTM’s sheave with bearing design provides the best mechanical
performance. It is also superior at detecting tension that is being added or
removed.
15
4.0 Changing Sheaves
1.0 Introduction
Do not use the CTM with cable
larger than indicated on the
sheaves. Overload and damage to the instrument may
result.
Do not mix sheave sizes. This
will result in inaccurate measurement and possible overload.
As you use the CTM on different diameter cables you must change to the
correct sheave size. To change sheaves, remove the hex head screws
pointed out in Figure 6 below. Replace the sheaves with the correct letter
sheave and reinsert the screws and tighten.
Insure sheaves installed agree with sheaves noted in the Wire calibration.
Exception: Sheaves match the wire diameter of the cable to be measured
and alternate calibration is selected as per section 5.2.
Insure that the wire rope is riding in the groove of all three sheaves.
Screws
1.1 Unpacking
This manual covers the setup and operation of the CTM Clamp Line Tensiometer. The CTM is a simple, accurate strand dynamometer. It is can be
clamped onto a cable, accurately determine the wire tension and be removed in seconds.
The CTM can handle multiple wire diameters, it can display live tension, dual
live/peak tension, average tension captured from several tests, dual tension/
temperature display and a check-tensioning graphical display.
With its battery-powered electronic interface, setup and operation is made
simple with on-screen prompts.
This manual covers the following:
• Unpacking
• Setup
• Operation
• Maintenance
• Troubleshooting
When you receive your CTM, unpack it and inspect the container and the
instrument for any damage. Report any problems to the shipping company
immediately and save the packing materials.
Insert 2 AA batteries into the battery compartment, shown in Figure 1. Your
CTM probably comes from the factory with the proper sheave size installed
and calibrated for your application. If not, follow the setup directions later in
section 3.0 Confi guration Mode and 4.0 Changing Sheaves.
Figure 7
Changing sheaves
1.2 Description
Figure 1
The CTM is shown in Figure 1 with the parts labeled.
Sheaves
Support arm
Lever arm
Front panel
Battery
compartment
14
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