Attachment 01 - Tensiometer Calibration Procedure.pdf

MTNW TENSIOMETER

CALIBRATION PROCEDURE

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MTNW Tensiometer Calibration Procedure

Measurement Technology Northwest designs and manufactures rugged winch control, wireline monitoring and instrumentation used in demanding oil & gas, commercial and oceanographic applications ranging from polar to tropical. Our products are used to control and monitor speed, payout, and tension in winch systems used for equipment deployment, barge positioning, fixed-place mooring, drawbridge controls, and wherever accurate and reliable line control is required.

Electrical and mechanical components can change over time due to wear and tear so it is best to calibrate a running line tensiometer at least once every year to provide the best accuracy possible.

This document will provide the recommended procedure for calibrating a running line tensiometer.

1. Calibration General Arrangement

Figure 1.0 Recommended Configuration for Multi-Point Calibration

a. Multi-point calibration

i. For accuracy of less then 1% of full scale over the capacity range, more points are needed to fit the tension curve.

b. Two-point calibration

i. For accuracy greater then 1% of full scale over the capacity range.

TENSION TEST

INSTRUMENT

POWER

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2. Tools and Instruments Required

a. Running Line Tensiometer (RLT)

i. Output signal: mA or mV

b. Wire Rope (Must be the same diameter and construction if available that will be used in the final application)

c. Tension Test Instrument

i. Tension Link / Dynamometer (For Multi-Point Calibration)

1. Output of this device should provide you with a unit of force.

a. ie: LBs, KG, Ton, MTon, Kip, etc.

2. Should be calibrated regularly by a certified professional with certificate.

3. Tension Link capacity should not be more than twice the full scale range of the tensiometer you are testing.

4. The recommended accuracy of the tension link should be at least 10% of the accuracy you want to see on the tensiometer.

(Example: You want the tensiometer to have an accuracy of +/-1% of

100 Kips.

You should use a use a 100 Kip tension link with an accuracy of +/-0.1%)

ii. Known Weight (For 2-Point Calibration)

1. Hanging Sand Bag

2. Hanging Water Bag

3. Cement Blocks

4. Rail Wheels

d. Tension Pulling Mechanism

i. Hydraulic Ram

ii. Winch System

iii. Chain Fall

iv. A known weight

e. RLT Measurement Device

i. LCI-90i, LCI-80x

ii. PLC

iii. Multimeter

iv. Other

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3. Procedure Overview

a. Warm-up

i. Required for the wire rope to properly set into the sheaves of the RLT.

ii. Apply the full scale tension and return to a zero-load state. Repeat five times.

iii. By the fifth pull to full scale, the RLT output signal should have a consistent and stable output.

b. Calibration

i. Calibration points are captured.

ii. The more points taken the better the RLTs accuracy will be.

iii. These points will consist of taking a tension measurement from the tension test instrument and relating it to the signal output of the RLT.

iv. Calibration points should be distributed evenly along the full scale capacity of the device that is being calibrated.

c. Verification

i. Verify the calibration points are repeatable.

ii. Apply tension to the system. Repeat the calibration points. Compare running line RLT output to tension test instrument.

4. LCI90i Multi-Point Calibration Procedure

a. Warm-up

i. On the LCI-90i display from the main screen push the DIAG button.

ii. Write down the tension measurement from the tension test instrument and the raw output signal (mA/mV) from the RLT.

iii. Apply the full scale tension to the system.

iv. Return the system to a zero-load state and record the low and high output of the

RLT.

v. Repeat 4 more times.

b. Calibration

i. From the startup screen navigate to the following.

1. MENUCALIBRATION

ii. Make sure the WINCH NUMBER for the device being calibrated is selected (i.e.

1 thru 4).

iii. Navigate menu to TENSION CALIBRATION.

1. MENUCALIBRATION TENSION CALIBRATION

iv. The screen should look like Figure 3 in Appendix A. If not, select CALIBRATION

MODE and change to LOOKUP.

v. Navigate the menu to CREATE/EDIT TABLE.

vi. The screen should now look like Figure 4 of Appendix A. Select table ‘A’ under

TABLE ID in which the data will be stored.

vii. Change the NUMBER OF POINT to the number of calibration points that will be used. (2-10 points possible)

viii. Make sure POINT TO EDIT is set to 1 and LIVE/EDIT is set to LIVE.

ix. Select INPUT SIGNAL and press ENT once. This will bring the up the current input signal on the selected device. Press ENT again and the signal will be captured.

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1. It is important that when ENT is pressed the second time that you are also grabbing the tension reading from the tension test instrument and writing that number down.

2. If the tension reading is to jumpy wait for the reading to settle before proceeding to the next point.

3. It is recommended that there is a small amount of tension on the line for the first calibration point. Bring the tension up to around 100-200 pounds.

x. Enter the tension value measured by the tension test instrument in DISPLAY

TENSION.

xi. Select POINT TO EDIT and advance it to the next calibration point.

xii. Increase the wire rope tension till the next calibration point is reached.

xiii. Repeat steps ix. to xii. until the last calibration point.

xiv. Press the RUN button to display the main screen.

c. Verification

i. On the LCI-90i display from the startup screen push the DIAG button.

ii. Return the system to a zero-load state.

iii. Record the output from the tension test instrument, the tension output for the

RLT and the output signal for the RLT.

1. It is recommended to record the all three pieces of information.

2. If the verification for the calibration point seems outside our the required accuracy, the tension test instrument number and RLT output signal can be re-entered into the lookup table to correct the error.

iv. Increase the wire rope tension till the next calibration point is reached.

v. Repeat step iii until all calibration points are verified to be within the required accuracy.

vi. Return the system to a zero-load state.

vii. Repeat the verification process a second time (steps iii thru.v).

viii. If all calibration points are verified twice to be within the required accuracy, the calibration is complete.

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Appendix A.

Figure 2. Example of 10-Point Calibration

2.2 TENSION CAL. WINCH 1

1 CALIBIBRATION MODE LOOKUP

> 2 USE TABLE ID. A

A A

B B

C C

D D

E E

8 CREATE / EDIT TABLE

Figure 3. LCI-90i Lookup Table Selection Screen

Warm Up Lookup Table

Verification Run 1

Verification Run 2

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2.28 CREATE LOOKUP TABLE

1 TABLE ID. A

> 2 NAME A

3 NUMBER OF POINTS 10

4 POINT TO EDIT 1

5 DISPLAY TENSION 1000.0 lbs

6 LIVE/EDIT LIVE

7 INPUT SIGNAL 4.560 mA

Figure 4. LCI -90i Lookup Table Creation Screen

CONTACT INFORMATION

4211 24th Ave West Seattle WA 98199

USA

Phone: 206.634.1308 Fax: 206.634.1309

Email: LCI@mtnw-usa.com Copyright 2013