Technical Description 5-7
Microprocessor
The CPC incorporates an Intel 80188 microprocessor to control all
its functions. The microprocessor uses a 32KB EPROM
*
chip for
program memory and an 8KB RAM
**
chip for making calculations
and running count buffers. An additional 8KB of EPROM stores
nonvolatile information such as the photometric calibration.
An analog-to-digital (A/D) converter is connected to the
microprocessor and measures photodetector voltages,
temperatures, and flowrates. (The temperatures and flowrate
controls are based on the raw data received by the A/D converter).
Counters within the microprocessor keep track of the particle
pulses detected by the photodetector. The display, pushbuttons,
and RS-232 communications are also controlled by the
microprocessor.
Flow System
Figure 5-2 is a flow schematic of the CPC. The CPC has two inlet
flow options: high flow (1.5 L/min), low flow (0.3 L/min). The
flowrate through the sensor is always 0.3 L/min, independent of
the inlet flow. For information on how to enter these modes, see
“The Front Panel” in Chapter 3.
*
Electronically Programmable Red Only Memory
**
Random Access Memory
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