Cameron NUFLO 1141C, Руководство пользователя

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Scanner 1141 Hardware User Manual
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a debounce circuit
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a counter for the pulse input
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automatic dispensing of pulses to the pulse output ports
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interfacing to the serial ports
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simple output for controlling the A/D system
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analog outputs
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transmitter supplies
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the “watchdog” timer
Clocks and Timers
The CPU clock provides 7 MHz to run the microprocessor. In power-save mode, the CPU clock
automatically shuts down when the processor is inactive.
The real-time clock is a combined clock and calendar with leap years. It provides all timing
functions to the flow computer including the generation of the “heartbeat interrupt” (see
Power
Management below) which runs the real-time kernel. The real-time clock provides the accurate time
base for volume integration, estimation, history and data logging, and all other timing functions. The
real-time clock runs continuously; during power outages, it draws power from the memory backup
battery.
The “watchdog” timer prevents the microprocessor from stalling in a loop (e.g., the processor waits
for an input signal that never arrives). If a loop occurs, the Watchdog Timer resets the program to the
initial start point and normal operation continues. Watchdog Timer resets are logged in the Event
log.
Power Management
The Scanner 1141 uses a sophisticated power management system to optimize measurement and
control operations while minimizing power use. A single power input is required; all other supplies
are generated from the mainboard.
To conserve energy, the display automatically shuts down when it is not in use. A push-button switch
on the circuit board is pushed to “wake-up” the display. Any display item can be paused for viewing
by pressing the wakeup button.
A “heartbeat interrupt” pulse triggers the processor periodically for internal process operations.
When the power-saver mode is ON, the real-time clock provides a “heartbeat interrupt” signal that
turns the CPU ON every 1/32 of a second. During this momentary ON period, the CPU performs any
pending tasks. If no tasks are pending, the CPU shuts itself off.