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W450769A 01/14
3.5.3 Function Kickout Fuse (Fus1)
The computer unit contains a standard 10 AMP replaceable fuse. The fuse protects the function kickout
circuit and relay contacts, if a short circuit occurs across the crane kickout solenoids. Replace the fuse
if the system error codes indicate that the function kickout power feed is missing. Ensure the crane
circuit breaker is closed and power from the crane is present.
NOTE: Prior to replacing the fuse, ensure any electrical shorts which may have caused the failure of
the original fuse have been removed
.
3.5.4 Pressure Sensors
There are two pressure sensors installed as part of a MicroGuard® RCI-510 System. Both pressure
sensors are mounted within the computer unit. One is connected to the PISTON side of the boom hoist
cylinder via flexible hose; the other is connected to the rod side of the boom hoist cylinder via flexible
hose. Both hoses are protected by velocity fuses within the boom hoist cylinder valve block on the end
of the cylinder(s).
The pressure sensor located on the piston side, is subject to the hydraulic pressure needed to support
the weight of the boom, any attachments, and the load. The pressure sensor on the rod side monitors
the pressure necessary to control the down motion of the boom. The computer unit uses this
information (along with other sensors such as extension, length, and angle), to compute the weight of
the suspended load. The maximum continuous working pressure for the sensors is 250 bar (3625 PSI).
WARNING!
BOTH PRESSURE SENSORS ARE PRE-CALIBRATED FROM THE FACTORY AND
SUPPLIED AS PART OF THE COMPUTER. THE PRESSURE SENSORS MAY NOT BE
INDIVIDUALLY REPLACED. REMOVAL OR REPLACEMENT OF THE PRESSURE
SENSORS FROM THE COMPUTER INVALIDATES THE WARRANTY AND WILL
ADVERSELY AFFECT THE PRESSURE CALIBRATION. ANY SERIOUS PROBLEM WILL
NECESSITATE CHANGING THE ENTIRE COMPUTER UNIT.
Checking Pressure Sensors
1. Lower the boom until the boom hoist cylinder is completely retracted and on its stop.
2. Loosen both hydraulic connections to the pressure sensors to ensure zero pressure is present
on the sensors.
3. Enter the CALIBRATION MODE and use the “PRESSURE MONITOR” command to view both
sensor pressures and net pressure.
4. Check the PRESSURE values of both sensors. They should be between -75 and + 75 PSI. If
not, replace the computer unit.
5. Check the NETT pressure values of both sensors. This should be between -35 and +35 PSI. If
not, replace the computer unit.
