Thermo Scientific 5028i Instruction Manual page 225

Firmware
Instrument Control
Monitoring Signals
Output Communication
Thermo Fisher Scientific
The processor firmware tasks are organized into four areas:
Instrument control
l
Monitoring signals
l
Measurement calculations
l
Output communication
l
Low-level embedded processors are used to control the various functions
on the boards, such as analog and digital I/O. These processors are
controlled over a serial interface with a single high-level processor that
also controls the front-panel user interface. The low-level processors all
run a common piece of firmware that is bundled with the high-level
firmware and loaded on power-up if a different version is detected.
Each board has a specific address that is used to identify to the firmware
what functions are supported on that board. This address is also used for
the communications between the low-level processors and the high-level
processor.
Every tenth of a second, the frequency counters, analog I/O, and digital
I/O are read and written to by the low-level processors. The counters
are accumulated over the past second and the analog inputs are averaged
over that second. The high-level processor polls the low-level processors
once per second to exchange the measurement and control data.
Signals are gathered from the low-level processors once per second,
and then processed by the high-level processor to produce the
final measurement values. The one-second accumulated counts are
accumulated and reported for the user-specified averaging time. If
this averaging time is greater than ten seconds, the measurement is
still reported every 10 seconds. The one-second average of the other
analog inputs are reported directly (no additional signal conditioning is
performed by the high-level processor).
The front panel display, serial and Ethernet data ports, and analog
outputs are the means of communicating the results of the above
calculations. The front panel display presents the concentrations
simultaneously. The display is updated every 1-10 seconds, depending
on the averaging time.
The analog output ranges are user selectable via firmware. The analog
outputs are defaulted based on the measurement range. Negative
concentrations can be represented as long as they are within -5% of full-
scale. The zero and span values may be set by the user to any desired
value.
System Description
Firmware
Model 5028i Instruction Manual 8-5