CADD Legacy Plus 6500 - Software Safety Features

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Reference
Section 5: Reference
Software Safety Features
Hardware-related Software Safety Features
Program Memory Check
At power up and at regular intervals thereaer, the program memory is
tested by calculating a Cyclic Redundancy Code (CRC) on the program and
then comparing it with the CRC stored with the program.
If the stored and calculated CRCs do not match, the soware will display
a system fault screen, turn on a continuous two-tone audible alarm, and
stop all medication delivery.
RAM Memory Check
At power up, the random access memory is checked. A series of bit pat-
terns is written to and read from each address in the RAM. If the read
data is dierent from the written data, the soware will display a system
fault screen, turn on a continuous two-tone audible alarm, and stop all
medication delivery.
Motor Circuit Check
At power up and at regular intervals thereaer, the motor circuit is
checked to ensure that no power is being applied to the motor unless
the motor is actually on. If the soware detects power being applied to
the motor at any other time, it will sound a continuous two-tone audible
alarm and will no longer attempt to deliver medication. During every
pump activation, the soware checks to see whether the motor completes
one activation. If the motor fails to turn, or fails to complete a cycle, the
soware will display a system fault screen, turn on a continuous two-
tone audible alarm, and stop all medication delivery.
Keyboard Encoder Check
Every time the soware receives data from the keyboard encoder, it is
checked. If the data is not a valid key press, the soware will disregard
the key press. e keyboard is designed with redundant switches for
‹
and
⁄
. e soware must detect that both switches are activated
before taking any action.