User's Manual

23 LS420 Universal User Manual V2.91 2003-01-21.doc
2.6.4 Radius display troubleshooting
For accurate radius calculation the actual boom length and angle, and the jib length and angle
must be correctly displayed by the LS420 and the calibration parameters described in section
2.6.1 must be correctly measured and entered in the advanced options of the LS420 display.
Before proceeding with troubleshooting confirm that the radius calibration procedure described
in section 2.6.1 has been followed correctly. The most common reason for error is caused by
incorrect slew offset compensation. If the difference between the radius displayed and the ac-
tual radius remains constant through all boom angles and boom lengths the slew offset should
be adjusted accordingly.
Some booms bend significantly with a load on the hook, thus reducing effective radius. Boom
deflection can be verified if the displayed radius is equal to the actual radius with the boom at 0°
and at 90° but greater at a boom angle of 45° (boom deflection is greatest at 45°). Furthermore,
the effect of boom deflection is greater when the boom is longer. To compensate for boom de-
flection adjust the boom deflection value in the advanced options of the LS420 display. Follow
the steps below to determine the appropriate boom deflection compensation value.
Step 1) Raise the boom to 45° with a known load.
Step 2) Compare the radius displayed with the actual radius. Change the boom deflection
compensation value and again compare the radius displayed with the actual radius. Adjust
the boom deflection value until the radius displayed equals the actual radius.
Tip:
with the boom at 45° and the maximum load on the hoist, the boom deflection
compensation value should equal the difference in feet between the radius displayed
and the actual radius. With the boom at 45° and half the maximum load on the hoist,
the boom deflection compensation value should equal twice the difference in feet be-
tween the radius displayed and the actual radius. Etc.
Note: the "No Ld Defl" (no load deflection) value permits compensation for booms that deflect
significantly under their own weight, even with no load on the hoist. This value should only be
adjusted in consultation with LSI. For any information contact LSI: see page 2 of this manual.
2.6.5 Calibration of angle display with non-LSI angle sensors.
LS420 requires accurate boom angle information to display radius correctly. If a non-LSI
pendulum type angle sensor is to be used it must be correctly calibrated before proceed-
ing with radius calibration.
Step 1) Place the boom at a known angle.
Step 2) Compare the angle displayed with the actual angle. Adjust the angle offset (or offset
AD2) in the advanced options of the LS420 display to compensate, e.g. if the angle displayed is
1.5° greater than the actual angle, subtract 1.5 from the angle offset value.
Step 3) Verify that the boom angle displayed equals the actual boom angle.
Note: the "scale ADC2" value should only be adjusted in consultation with LSI. For any informa-
tion contact LSI: see page 2 of this manual.