PROXIMITY DETECTION SYSTEM
Presented by
PAMICOR GRADUATE TRAINEES

•Proximity: nearness in space
•Proximity Sensor: a sensor that performs non-contact
detection in comparison to sensors such as limit switches that
detect objects by physically contacting them
•A Proximity Detection System (PDS) is designed to slow
down and stop the machine if there is identified a risk of
collision with a person or an object carrying a tag
•The Proximity Interface (PI) is an interface between a
Proximity Detection System (PDS) and a machine

• Depending on the installed PDS model, automatically
generated alarms can be used that instruct personnel to take
corrective or preventative action to avoid a collision.
• Possible technologies that generate required sensor
information to enable detection of close encounters between
two or more objects could include localization, proximity
detection, ranging, and zone control/area isolation.

• In a Sandvik machine, PI system communicates with the control
system of the machine via a CAN bus.
• The control system controls the proportional brake valve based on
requests of the PI system.
• The activation time of Proximity Interface components and
hydraulic system of the brakes from signal state change in the
control module output to the commencement of braking is a
maximum of 700ms.
• If the control system detects a fault in the machine, controls of the
PI system are overridden.

SYSTEM STATES
Safe state
The safe state is an equipment condition where the PDS has not
detected a tag around the machine. The machine can operate
normally.
Caution state
The caution state is an equipment condition where the PDS has
detected a tag inside the caution zone. The PI system limits the
maximum speed of the machine to the parameter defined speed. If
the speed limit is exceeded, the PI system controls the machine
brakes to slow down the machine.

Warning state
• The warning state is an equipment condition where the PDS has detected a
proximity tag inside the warning zone. The PI system limits the maximum
speed of the machine to the parameter defined speed. If the speed limit is
exceeded, the PI system controls the machine brakes to slow down the
machine.
Stop state
• The stop state is an equipment condition where the PDS has detected a tag
inside the stop zone. The PI system engages the parking brake.
Fault state
• System diagnostics has detected a fault situation and the machine is set to the
limp mode.

• The PD interface slows down and stops the machine if the
proximity inputs are activated by the PDS. Operator can any
time exceed the applied braking force by pressing the brake
pedal.
• PD Interface has certain limitations to slowdown or stop the
machine. Collision with another vehicle or person could
cause death or severe injury.
• PD System must never be seen as the only control to avoid
accidents. Drive at safe speed and slowdown the machine
always when other traffic is in working area.

Operation in case of a detection
• Caution zone
• If an object (wearing a tag) is detected inside the caution zone, the
throttle pedal position is overridden, and the service brakes are
activated with increasing braking force if the speed of the machine
is more than 10 km/h.
• Once the speed limit has been achieved, the brakes are released, the
2nd gear is set and the throttle pedal is controlling speed of the
engine. The speed and gears are limited until the caution zone is
clear of detection tags.
• The converter lock-up is not automatically released in the caution
zone, but the activation is prevented by the control system.

Operation in case of a detection
Warning zone
• If an object (wearing a tag) is detected inside the warning zone, the
throttle pedal position is overridden, and the service brakes are activated
with increasing braking force if the speed of the machine is more than
5 km/h.
• Once the speed limit has been achieved, the brakes are released, the 1st
gear is set and the throttle pedal is controlling speed of the engine.
• The speed and gears are limited until the warning zone is clear of
detection tags.
• The converter lock-up is not automatically released in the warning zone,
but the activation is prevented by the control system.

Operation in case of a detection
Stop zone
• If an object (wearing a tag) is detected inside the stop zone, the parking
brakes will be engaged and an alarm/warning will be shown to the
operator.
• The parking brakes cannot be released until the stop zone is clear of
detection tags. When operating in the Remote Control mode, the
parking brake button of the remote controller stays in the released
position in case of a detection.
• The parking brakes will not be released even if the detection tag leaves
from the stop zone. The parking brake must be engaged and released
from the remote controller before the tramming can continue.

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