User's Manual

19 LS420 Universal User Manual V2.91 2003-01-21.doc
2.5 Installation of a length sensor cable reel
Step 1) Install the reel on its solder tab on the main boom. The cable reel is usually installed
on the main boom’s lower section on a clear area. Guides should be placed along the boom
sections and a cable anchor near the boom head.
Step 2) Feed the cable through the cable guides and pull on it to attach it to the cable anchor.
There should be minimal tension on the cable reel spring when the boom is fully retracted. Ver-
ify the boom length as shown on the appropriate operation
screen of the display unit. Please consult your Quick Reference
Guide to find the length display for your specific LS420 system
configuration. The boom length should represent the actual total
boom length from the boom pin to the head sheave center, however, depending on the exact
placement of the cable reel and cable anchor the displayed length may differ from the actual
length. Note the difference to the tenths of feet.
Step 3) Adjust the length displayed: press the hoist button re-
peatedly until the display shows the advanced options entry
screen. Press the test button to enter the advanced options, and
then press the hoist button until the display shows “Trim
Length” or “Offset AD1”. Use the limit+ and limit– buttons to
enter the difference noted above, to the tenths of feet. Note: For
“Offset AD1” the decimal point may be hidden so, if the length
displayed is 10 feet too short, the trim length factor must be set
to 100 (10.0 ft) and if the length displayed is 6 feet 6 inches too
long, the trim length must be set to – 65 (- 6.5 ft). When finished,
press bypass to return to the main operation screen. For help with the buttons of the display
please refer to the quick reference guide or section 1.3 of the user manual.
IMPORTANT! Step 4) Test: verify that the display correctly shows boom length when com-
pletely retracted and when fully extended. It is safer to have someone helping to ensure that the
reel has enough cable to reach full crane extension.
Cable anchor
Cable guide
Cable reel
Boom base pin
Boom length: distance
from boom base pin to
head sheave center.