10 Error handling
Positioner DC 6-06
61
10.5.1
Bootloader Start Tests
The next section describes the tests performed by the bootloader and the resulting
actions. Communication with the unit is not possible while the tests are in progress,
especially when the program sticks in an endless loop because of a fatal error. This is
why different types of display on the control units are used to indicate the current test
mode.
Watchdog Test
Type of display in the event of an error: Error lamp is on
The test checks whether the watchdog built into the processor is operational. This
purpose of the test is to ensure that in an undefined program flow, the control unit
enters a safe state after a defined time. If the watchdog test is negative, the bootloader
program stays in an endless loop and the said display stays on.
Internal RAM Test
Type of display in the event of an error: Error lamp is on
Different bit patterns are read to the internal processor RAM memory and read back
again. If at least one cell does not contain the expected code, the bootloader program
enters an endless loop and the said display stays on.
Bootloader Program Test
Type of display in the event of an error: Error lamp is on
A checksum is calculated over the memory area that contains the bootloader program
and is compared with the checksum programmed at the factory. If they do not match,
the bootloader program stays in an endless loop and the said display stays on.
Control Unit Program Test
Type of display in the event of an error: Error lamp flashes:
three times short, long off, three times
short, ...
A checksum is calculated over the memory area that contains the control unit
program and is compared with the programmed checksum. If they do not match, the
bootloader enters a state in which the error 3087
ErrMainCheckSum
is displayed via
the serial communication (DcDesk 2000 PC program or hand programmer).
Watchdog Tripped
The bootloader enters a state in which the watchdog error 3089
ErrWatchdog
is
displayed via the serial communication (DcDesk 2000 PC program or hand
programmer).
Summary of Contents for PANDAROS DC 6-06
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