Power Supply Unit And Communications Board; Pressure Sensor And Encoder Board - Cardinal Health Alaris GW Technical & Service Manual

Circuit Descriptions
Circuit Descriptions

Power Supply Unit and Communications Board

Power module
The selection of 115V or 230V is made via S1. The secondary is rectified to an unregulated DC Voltage. F2 is a Polyswitch resetable fuse.
The raw DC is output to the Control PCB. The battery is connected via JP3, the maximum current being limited by F1.
RS3 & Nursecall
The external RS232 connection is made via JP5 where power for the 4kV isolated interface is taken from pins 4 and 7. This voltage is
converted to a 5-volt supply and in turn converts the RS232 communications levels to TTL which are then sent to the Microcontroller.
The Nursecall interface is controlled from the Microcontroller to energise the relay which causes the contact to change over.
IrDA Module
IrDA or RS232 is selectable. The IrDA communication signal is output from IC7.

Pressure Sensor and Encoder Board

Motor encoder
Diodes D1 and D2 are the emitters in the motor encoder and OPT1 and OPT2 being the receivers. The signals are sent to the Control
PCB where they are used in conjunction with the Pressure Sensor and Encoder PCB to provide a quadrature detection scheme from the
rotary encoder on the drive motor. These signals are then processed via the Microcontroller.
Pressure sensor
The strain gauge is connected to the Pressure Sensor PCB, the sensor o/p signal is then amplified and then output to the Control PCB
and used to provide a second stage of amplification for the pressure sensor signal. This signal is processed via the Microcontroller.
Alaris® GW Volumetric Pump 30/77 1000SM00006 Issue 4