Rosemount TankRadar Rex DAU 2100, Руководство по обслуживанию

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3-27
Rosemount Tank Radar Rex
Chapter 3 Device Description
Service Manual
308012En, Ed.2
May 2013
3.3.7 Database Registers
The DAU’s database is stored in a nonvolatile memory (it will retain its
contents even if the power is turned off), a serial EEPROM. The
database is copied to a part of RAM that acts as a Shadow RAM in order
to increase performance when accessing the database. The database
contains tank specific values like the height of the temperature sensors.
At start up the software determines whether it was a power on or a reset
from the Watchdog. At power on it tests the checksum of the program
stored in the EPROM, and runs a test of the entire RAM. If any faults are
found, these are flagged in status registers. Then the checksum in the
database is tested. If it is OK, the data base is loaded into the shadow
RAM. If it is not OK, this is indicated in status registers, and a default
database is restored in the EEPROM and RAM.
The program will also conduct memory tests during the usual chores.
The RAM test is run approximately every 20:th second. The EPROM and
EEPROM tests are run at intervals of 80 minutes separated by 40
minutes. It takes two consecutive errors to be detected before the error is
signaled to the bus-master.
3.3.8 Local Display
The DAU is equipped with an LCD-display as a Local Readout function.
The display shows the level of the associated RTG, values measured by
the DAU itself and error codes.
Figure 3-20. DAU LCD-display
Data Acquisition Unit Type DAU 2130
EEx C T4
T
amb
=-40° to +65°C and D. Temperature Code T4. The device
Group C Hazardous Location Class
TankRadar L/2
UL
Ex