Motor Encoder Pcb; Interface Pcb; Air In Line(Ail)/Safety Clamp Housing; Door Detect Flexible Pcb - CareFusion Alaris GP Technical & Service Manual

Alaris® GP Volumetric Pump
Circuit Descriptions

Motor Encoder PCB

The Motor Encoder PCB sits above the encoder wheel. The wheel consists of two discs one with multiple teeth the other with a single
slot. The wheel with the multiple teeth runs through a dual channel slotted optical switch which produces two digital encoder signals.
The fluid delivery processor is able to interpret the phase and frequency of these signals to determine the speed and direction of the
cam shaft. The disc with the single slot runs through a single channel slotted optical switch that produces a single digital signal from
which the mechanism can be set into the park position.

Interface PCB

The Interface PCB provides all the low level control and monitoring functionality of the system. It is broken into the following functional
blocks:
Fluid Delivery Processor Module
This module provides the interface between the motor drive and sensor systems and the main processor.
Drop Sensor Module
This module provides the interface between the fluid delivery processor and an IVAC® 180 Flow Sensor. It incorporates automatic gain
control to minimise the effects of fogging and changes in ambient light levels. Connection of the drop sensor is automatically detected.
Pressure Measurement Module
The fluid delivery processor connects to the upstream and downstream pressure transducers via its internal analogue to digital
converter. The fluid delivery processor is able to determine if the sensors are working correctly by monitoring the voltage across the
force transducer and by switching in a known off set to the amplifier.
Encoder Interface Module
Using optical encoders the fluid delivery processor is able to determine the direction and speed of the motor, the position of the cam,
the status of the door seers and the flow stop device.
Air In Line Module
This is an ultrasonic system used to detect air bubbles in the line. A swept frequency signal is used to excite the piezo crystals in the AIL/
Safety Clamp Housing. When fluid is present in the tube the signal is coupled across the gap and received by another piezo crystal. The
received signal is amplified and passed through a detector to indicate whether air or fluid is present in the line.
Motor Drive Module
The fluid delivery processor generates three PWM control signals which are used to determine the amount of current flowing through
each phase of the stepper motor. The motor is driven using micro steps. The Safety Processor is able to prevent operation of the motor if
it believes that a system fault has occurred.

Air In Line(AIL)/Safety Clamp Housing

The AIL/Safety Clamp Housing contains the ultra sonic piezo transducers used by the air in line system.
These transducers connect to the Interface PCB via the Air In Line Flexible PCB. A reflective optical sensor in the AIL/Safety Clamp
Housing allows the fluid delivery processor to determine the status of the seers used to retract the flow stop. A photo transistor and
a photo diode are used to determine if the Safety Clamp slide is open or closed. All the drives to the optical sensors are modulated to
prevent cross talk and determine correct operation. The optical sensors connect to the Interface PCB via the Safety Clamp Detect Flexible
PCB.

Door Detect Flexible PCB

The status of the door is monitored using a magnet embedded in the door frame and a digital Hall Effect device mounted on the end of
the Door Detect Flexible PCB.

Battery Pack

The battery pack contains a smart gas gauge device that provides charge information to the charger and the status of the battery
(capacity, voltage, current and temperature) to the main processor. The pack also contains a thermal fuse and thermal cut out. The
battery will be charged when ever the unit is connected to the main supply.
1000SM00013 Iss. 4 46/80