Software Safety Features - SIMS Deltec CADD-Legacy PLUS Operator's Manual

Section 5: Reference

Software Safety Features

Hardware-related Software Safety Features
Program Memory Check
At power up and at regular intervals thereafter, 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 software will
display a system fault screen, turn on a continuous two-tone audible
alarm, and stop all drug delivery.
RAM Memory Check
At power up, the random access memory is checked. A series of bit
patterns is written to and read from each address in the RAM. If the
read data is different from the written data, the software will
display a system fault screen, turn on a continuous two-tone audible
alarm, and stop all drug delivery.
Motor Circuit Check
At power up and at regular intervals thereafter, the motor circuit is
checked to ensure that no power is being applied to the motor
unless the motor is actually on. If the software 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 software checks to
see whether the motor completes one activation. If the motor fails
to turn, or fails to complete a cycle, the software will display a
system fault screen, turn on a continuous two-tone audible alarm,
and stop all drug delivery.
Keyboard Encoder Check
Every time the software receives data from the keyboard encoder, it
is checked. If the data is not a valid key press, the software will
disregard the key press. The keyboard is designed with redundant
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