TENSITRON ACM-100 User manual

Operating Instructions
ACM-100
Aircraft Cable Tension Meter

The ACM-100 is shipped calibrated and ready to use
on 1/16", 3/32", 1/8" and 5/32" diameter aircraft cables.
O
OPERATION
1. Memory lock system must be "off." To set in the "off" position push the memory lock
button down fully, so that the red flag is not showing (reference Figure 1).
2. Determine the diameter of the cable to be checked. For example, in Figure 1 the cable
diameter to be tested is 3/32". Rotate the riser so the number 3/32 faces you and clicks into
place. This automatically aligns the back of the riser with the two flanged reference pivots.
3. Open the closure bar by gently pushing it through the handle. This raises the reference
pivots.
4. With the closure bar open, engage the meter onto the cable. Position the cable under the
two reference pivots and over the top of the riser. Squeeze the handle back to the “closed”
position.
5. With the meter now locked onto the cable, note where the pointer is on the dial. Refer to
the calibration chart on the back of the instrument and locate the column for the cable
diameter size you are testing. Then find the row in this column with the number closest to
the one the pointer is on.
6. Follow this row all the way to the left until you come to a number in the “TENSION IN LBS”
column—this number is the true tension of the cable.
7. For example, in Figure 1 the pointer indicates “30” on the dial. Locate the number 30 in the 3/32”
column. Follow this row to the “TENSION IN LBS” column where you see the number 20. Thus,
in this example the true cable tension is 20 lbs.
MEMORY/POINTER LOCK FEATURE
1. Use the memory lock to make a tension reading where the dial cannot be seen. Insert the ACM in
the hidden area. Open meter and clip flanges over cable. Close meter securely. Push the memory
lock button UP as far as possible, exposing the red flag. Remove the ACM from the cable and note
the reading. To clear the reading and return the pointer to zero, push the memory lock button on top
of the instrument fully down.
2. If the memory lock button is pushed up when meter is not in use, you may see the needle move from
1/2 to 1 1/2 dial increment lines. If the memory lock feature is used correctly very little of this
motion is transferred to the actual readings taken. The full-scale accuracy will still be well within
4%.
Before each use:
 Verify that the serial number on the instrument and the calibration
chart match, as readings may vary among instruments.
 The pointer must be resting at 0 on the dial. If the pointer is not
resting at 0, the calibration should be checked.
 Check that the calibration and certification are current.
ACM-100 Operating Instructions Page 1

3. Tension on aircraft cables may vary substantially with differences in temperature, stretching
or manufacture. For greater accuracy it is recommended that several readings be taken at
different locations on the cable and these readings averaged, to compensate for varying
cable thicknesses.
RECALIBRATION
Tensitron provides immediate turnaround service(s) for its instruments needing repair
and/or re-certification. All values tested are traceable to national standards and serviced
instruments meet or exceed all civilian and military specifications. A certification form
listing all calibration data and values is included with each instrument.
If recalibration is done in the “field”, follow the procedures below.
1. Photocopy the blank calibration chart, Figure 2, in preparation for gathering new
values.
2. If pointer is not resting at the 0 position on the dial, unscrew the socket plug located
on the bottom left of the instrument body. Using a small screwdriver, gently adjust
the zero adjust screw until the pointer indicates 0. After adjustment apply torque-
seal or paint to lock the screw head.
3. To simulate tension loads on cables, suspend a 5’ length of aircraft cable from
overhead. Next, apply known weights to the bottom of your cable in the increments
you wish to test. This type of calibration procedure is called a Dead Weight
Calibration. Note: Tension on a cable can be defined as the exact value of a
suspended weight from the cable. For example, a 100 lb weight hanging freely from a
cable will tension the cable to exactly 100 lbs. Only simulate tensions using free-
hanging weights on correctly-sized cable material. Never use any device that
attempts to convert rotational torque values into tension loads, as these types of
systems are highly inaccurate.
4. Determine the correct riser for the cable diameter to be tested by referring to the
calibration chart. Rotate the riser so that the correct number or letter faces you and
clicks into place. This automatically aligns the back of the riser with the two flanged
reference pivots.
5. Insert the instrument onto the tensioned cable making certain that all three contact
points (the two outer flanged reference pivots and the center riser) contact the cable.
When to recalibrate:
a. Pointer does not reset at 0 with memory lock "off."
b. Instrument has been dropped.
c. For use on aircraft, the ACM-100 must be calibrated at intervals
not to exceed 12 months. Check that the calibration and
certification are current.
Page 2 ACM-100 Operating Instructions

Memory Lock Button
Rotating Riser
Closure Bar
3/32
Reference Pivots
OPERATING INSTRUCTIONS FOR
ACM-100 CABLE TENSION METER
Figure 1
ACM-100 Operating Instructions Page 3

6. Note where the pointer is on the dial and enter the new value onto your calibration work
sheet. We suggest taking several readings at different locations along your cable and
averaging the results before entering the new value.
7. Repeat this process for each cable diameter and tension values, making certain that your
new calibration chart has been signed, dated and attached to the instrument.
8. If tension value is considered “critical”, remove the cable from the aircraft and perform a
dead weight calibration.
Note: If calibration results differ greatly from the original calibration, or if minimum or maximum
values cannot be indicated on the instrument dial, return to Tensitron for service.
Page 4 ACM-100 Operating Instructions
ACM-100 Serial No.
If Cable Size is: 1/16" 3/32" 1/8" 5/32"
USE RISER 1/16 RISER 3/32 RISER 1/8 RISER 5/32
Actual Tension on
Cable in LBS =
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
TENSITRON, INC.
CAL. BY: __________________ 733 S. Bowen St. - Longmont, CO 80501
Date: See Cal Sticker
TEL: [phone] FAX: [phone]
Figure 2
TENSITRON, INC.
733 South Bowen Street
Longmont, CO 80501
USA
Phone: [phone]
Fax: [phone]
Email: tensionmet[email protected]
Web Site: www.tensitron.com