Distributed Processing; Module Communication - GE B30 Technical Reference Manual

B30 Patient Monitor

2.3 Distributed processing

This is a multiprocessor system. All parameter modules have their own microprocessor, which
performs functions such as module key control, waveform filtering, parameter related
computing and pneumatic control, etc. At the same time the main CPU performs higher level
tasks such as trending and alarm control. While the parameter modules and CPU are
performing their tasks, the UPI (Universal Peripheral Interface) microprocessor handles all
functions needed to transfer data between the parameter modules and the CPU.
This kind of parallel processing gives one major advantage to centralized processing. When
new parameter modules are added to the system, the processing power is increased. As a
result, the system does not slow down when new features are added.

2.4 Module communication

The communication master controlling data transfers between the CPU and parameter
modules is called UPI processor. It sends data to each connected module 100 times a second.
Modules respond to each data request immediately by sending a data package, whose length
depends on the type of the module. This communication protocol ensures that each module
receives and sends data every 10 ms. If a module does not respond to data requests, the UPI
processor presumes that the module is disconnected.
Parameter modules may hold a static (fixed) or dynamic address, which the UPI processor uses
when sending out data. Two parameter modules of the same type must not be fitted onto the
same monitor since they might reply to a data request simultaneously, thus causing
communication errors.
Figure 3
The UPI processor collects and stores all data that is received from the parameter modules into
a shared SRAM, which is mapped directly to the address space of the main CPU. The main CPU
reads data from the memory while the UPI processor guarantees that the data is up to date.
This operation also works in the other direction. In this the main CPU fills the shared SRAM with
data and the UPI processor distributes it to the parameter modules.
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Document no 2044677-001
Shared
SRAM
Control
Logic
Principle of UPI section operation
Voltage Temp
Meas Meas
Analog & Digital outputs
UPI
Module Bus
Processor
ComWheel Interface
Keypad Interface