Block Diagram Theory; Figure 26: Block Diagram - Nellcor OXIMAX N-595 Service Manual

Block Diagram
Theory
N-595
The monitor block diagram is shown in Figure 26 on page 113.

Figure 26: Block Diagram

The N-595 main printed circuit board (PCB) consists of three main parts:
• The Secondary Input Port/Secondary Output Port (SIP/SOP)
• The FE-102 front end
• The User Interface (UIF).
The SIP/SOP and the FE-102 front end are both electrically isolated from the
UIF. The FE-102 is electrically isolated to reduce capacitive coupling to earth
ground and improve the FE-102's ability to read difficult patients. The SIP/
SOP is isolated as mandated by regulations for patient safety.
The N-595 contains a microprocessor (Motorola MPC823 Power PC) and a
microcontroller (Microchip PIC17C756). The microprocessor provides the
bulk of the functionality in the pulse oximeter, acting as the master controller.
The microcontroller controls the FE-102 analog front end. The two processors
communicate by means of an asynchronous serial link between the two
processors over an isolated barrier.
Technical Discussion
113