6141.22X Incubator 8000 IC/SC/NC
Function Description
09.99 Page 28 of 49
2.3.1.4 INOP
Serious hardware or software faults result in complete failure of the incubator. The following
alarm messages are given:
- The INOP-LED lights.
- Continuous horn tone (cannot be deactivated).
The equipment is not serviceable.
Additional for Incubator 8000 IC:
If after switch-off of the 02 module within a few minutes an increase of the 02 concentration by
more than 3 Vol. by. % is detected this will also lead to an INOP message:
- INOP-LED lights.
- Continuous horn tone (cannot be deactivated).
The current 02-actual value is displayed flashing.
2.3.2 Software
All software routines described below (except test for RAM battery backup) that detect a failure
condition will cause an INOP alarm.
2.3.2.1 RAM test
After power is turned on, a complete test of the RAM (Random Access Memory) addressing
range of the microprocessor is performed. Specific bit patterns are used and move through the
RAM area. All RAM cells that are not used by the software are set to zero. During normal
operation of the software an ongoing RAM test is performed in the background. During this test
blocks of the RAM are swapped into a reserved RAM area. The RAM is then tested with the bit
patterns test scheme. All data transfer from and to the data block under test is secured by
CRC-calculations (Cyclic Redundancy Check).
2.3.2.2 Test of RAM Battery Backup
After power is turned on, the battery backed up RAM is checked by analyzing the contents of 5
test addresses. If a mismatch was detected, the continuous tone appears for approximately 4
seconds. Then the test addresses are rewritten with the proper information and a cold start is
performed which does not rely on the corrupted data in the battery backed up RAM.
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