156 AK 98™ Dialysis Machine - Calibrations
HCEN12630 Revision 07.2015
Program version 1.xx
7.1.4 I2C Data Bus Errors
The error codes for the I2C data buses are:
● 0623 xxx yyy and 0723 xxx yyy for the Control side
● 0223 xxx yyy and 0323 xxx yyy for the Protective side
If all error codes for a bus are issued it is most likely that one of the transducers has an
error that takes “down” the whole bus.
The best solution to the problem is to disconnect one transducer at the time until only
one error code is issued. Then the disconnected transducer is the faulty one and
should be exchanged for a new one. If error codes for more than one data bus is
issued the error is probably due to some defect on the General I/O board.
7.1.5 Calibrations
The different transducers are calibrated in different ways. The pressure transducers
are calibrated in three steps (0 mmHg, -500 mmHg and +500 mmHg) while e.g. the
conductivity cells are calibrated in two steps (0.0 mS and 14.0 mS)
The calibration of the UF cell differs radically from the rest, and requires a so called
calibration station.
7.1.6 Why is calibration needed?
No transducer is ideal – all transducers have two basic errors: a sensitivity error and
an offset error:
To compensate for these two, the machine shall calculate an offset value which will
bring the line to cross through the zero point, and a calibration coefficient – a factor,
typically between 0.90 – 1.10 which will correct the slope of the line so it matches the
ideal.
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