MicroGuard
®
434/500 System — Troubleshooting Manual PN W453200 Rev C 08/01/00
GREER COMPANY 1918 E. Glenwood Place Santa Ana, CA 92705 Telephone: (714) 259-9702 FAX: (714) 259-7626
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Crane Systems
2.4.2 DISPLAYED LOAD OR RADIUS ERRORS
This section gives direction to fault diagnosis of load and radius errors as displayed on the display
console. Load or radius errors may give rise to early or late tripping of overload alarms. Accuracy
of load, radius, length, and angle is determined by the correct installation and maintenance of the
system sensors.
Accuracy of load is governed by the radius accuracy, and the extension, angle, and pressure
sensors.
Accuracy of radius (unloaded) is governed by the extension and angle sensors.
Before continuing, make sure that there are no system faults.
•
CHECK BOOM EXTENSION
1. First check that the boom is fully retracted.
2. Check that the extension reel-off cable is correctly layered as a single layer across the
extension reel surface. Any stacking of the cable will cause extension errors when the boom is
fully retracted, causing the System to exceed the 0.5 ft tolerance allowed by the computer for
boom mode selection. If the reel-off cable is stacking on the reel, see SECTION 6.2.
3. Check the zero of the extension sensor at the fully retracted boom position. Enter the
Calibration Mode (SECTION 10.2). Using the “SPAN” command (SECTION 10.4.5), select
sensor No. 2 to view the extension value in feet. The value of extension must be between -0.2
and +0.2, with the boom fully retracted. If the extension value is incorrect, follow the
EXTENSION SENSOR SETUP procedure in SECTION 6.5.
4. Fully telescope the boom and check that the displayed boom length value matches the
maximum length of the boom. If the length value is incorrect, follow the EXTENSION SPAN
calibration procedure in SECTION 6.5.3 .
•
CHECK MAIN BOOM RADIUS
1. Fully retract the boom and make sure that the crane configuration is correctly set up.
2. Boom up to about 45° and measure the radius. The measured radius must match the displayed
radius within +/- 0.2 ft. If it does not match, continue to the “CHECK BOOM ANGLE”
procedure. If it does match, continue to “CHECK PRESSURE SENSORS.”
Both procedures are on the next page.
SECTION 2
NOTE
The required accuracy of taped radius measurements is within 0.1 feet.
When taking radius measurements; always use a good quality tape that does not stretch.
The tape should be graduated in feet and tenths of feet. Always measure between the
swing center of the crane and the hook line, using a single part of line, with the crane
centered over front (rough terrain crane) or centered over rear (truck crane).