Operation; Control Circuit Components - nifty Mk 3 Seies Operating/Safety Instructions Manual

Height Rider/SP Series
Operating & Safety Instructions
4

Operation

4.1

CONTROL CIRCUIT COMPONENTS

4.1.1 GROUND CONTROLS
MASTER PROGRAMMEABLE LOGIC CONTROLLER (PLC): - Situated under the ground controls
canopy, behind the Ground Controls Station is the Master PLC. The main purpose of the Master PLC is
to process signals received from all areas of the control circuit on the machine and where appropriate
output these to a series of smaller digital modules to operate the relevant machine functions.
Also, during machine operation, the Master PLC is constantly receiving signals from the Platform PLC
(see Section 4.1.2) in order to monitor Safety Critical Functions. If for some reason any of these
functions became inactive the Master PLC would immediately disable the machine.
TILT ALARM: - Fitted to the superstructure behind the ground controls canopy, the tilt alarm is a solid-
state sensor, which monitors the inclination of the machine chassis. When the platform is in use, i.e.
Booms are raised, if the inclination exceeds the pre-set limit, it will disable the drive to the machine and
sound the alarm. In order to recover the machine, the platform operation is unaffected, allowing the
operator to restore drive by lowering the booms into the stowed position. It is then possible to drive
back onto level ground, fully restoring machine operation.
MULTI-TONE SOUNDER: - Situated inside the ground control station is a small electric sounder, which
is used to provide an intermittent beep whenever the machine is in operation. Pushing a green "power
control" button or depressing the foot switch in the platform (if fitted) will energise this sounder. This
serves to warn personnel of the operation of the machine. In addition, it is this device which produces
a ricochet type sound if a safety critical problem has been detected i.e. Tilt angle or Cage weight limits
have been exceeded;
Cage Weigh: - If the electronic load cell detects an overload condition it will sound continuously in
conjunction with the cage overload warning symbols shown on the digital display (See Page 27).
Battery management: - when a low battery state is reached, the "pulsing" of the D.C. motors is
mimicked by the sounder reinforcing the message to the operator to charge the machine.
HORN: - Located on the side of the ground control box is a horn, which is used as a manual alert, by
pushing the "Horn" symbol on the Platform control panel.
BOOM SWITCH: - Mounted on the links knuckle and operated by the raising of any boom, this switch
controls both the operation of the Tilt Alarm Sensor, and the speed control function. With the booms in
the stowed position, the Tilt Alarm Sensor is by-passed, allowing the machine to negotiate slopes in
excess of the permissible working angle, without isolating the drive function. At the same time, High
Speed drive (Depicted by a Hare Icon) is possible, as is fast throttle on those machines so equipped.
When the booms are raised the Tilt Alarm Sensor becomes activated and only Slow Speed drive is
permitted. These control functions are of primary importance to safety of the machine and operator;
under no circumstances should this control function be isolated or by-passed.
TELESCOPIC BOOM SWITCH: - Mounted inside the telescopic boom, this switch controls the
operation of the Tilt Alarm Sensor and Speed Control function as described in the previous paragraph.
20
English/USA – 05/15
Original instructions