AR FI7000, Руководство по эксплуатации и обслуживанию

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PL7004 Kit
10 Rev F
2.2.4 Optical Receiver/Power Supply
The probe is powered optically. The laser light is fiber-optically transmitted to the probe. The laser light is
received via an efficient photon (light) power to electrical power converter. The electrical DC power is then
regulated, split, re-regulated and distributed to power the probe. Commands to the probe arrive in serial
optical format from relatively short interruption of the laser light. During receipt of commands, power for
operation is maintained by using excess energy that was stored in capacitors during the laser-on time.
2.2.5 Optical Transmitter
The probe transmits responses via a low power optical transmitter, or photodiode. The photodiode is off, no
light, when there is no transmission.
2.2.6 Control Logic
Functions within the probe are controlled by an on-board microcontroller. Analog-to-digital (A/D) converters
are used to digitize the levels from the preamplifiers, the photon power converter voltage, and internal
temperature. The microcontroller corrects these values using on-board calibration tables and processes all
communication in and out of the probe.
2.2.7 Sampling
The control program (firmware) controls the collection of 12-bit A/D samples from each input in a rapid
sequence, repeated for 16 samples of each input, and completed in 1200 microseconds. This is sufficiently
short in time that the readings may be considered to have been taken at the
same time. (For best accuracy
users are advised to control the sample timing so as to request data when the field levels are not intentionally
being changed. Untimed changes can typically be resolved by making several measurement samples and
using values only after the readings have stabilized.) Typically, samples are taken only upon receipt of a host
request for measurement. The sampled data is digitally processed to calculate the measured field level. The
firmware applies probe specific factory generated probe calibration data. This data includes temperature
correction data based on the internal probe temperature monitor.
2.3 PROBE INTERFACE
The FI7000 Interface provides power and communication to the probe and houses the laser light source,
control logic, and communication interfaces.
2.3.1 Laser
The laser module provides photon (light) power to the probe. The laser module contains an embedded
Class 4 laser with a peak output of 500mW and a wavelength of 850mm.
2.3.2 Optical Receiver
The optical receiver is a conventional-packaged photodetector.
2.3.3 Power Supply
All circuitry is powered by a 5V DC power supply.