Hitachi 902 Service Manual page 101

(c) Evasion of sample carry-over due to sample probe and washing for evasion
(I) Condition for carry-over evasion
Sample carry-over is prevented by washing the sample probe.
(II) Method of carry-over evasion
The sample probe is washed at the timing just before pipetting the sample
whose measurement includes a sample carry-over washing-specified test
(between sample pipettings).
The sample probe is washed by the following method. The determined volume
(65 µL) of detergent is aspirated from the specified washing cup on the sample
disk and discharged into the washing bath where the sample probe is washed
with water. At this time, stirring is not made.
(III) Tests with sample probe washing
Tests of control sample and standard solution are excluded.
(IV) Sample probe washing cycle
The sample probe is washed in one cycle time. Washing of the sample probe
will not degrade throughput.
(V) Registration of carry-over evasion-specified pattern
Up to 8 kinds of patterns, for which the evasion of carry-over due to the sample
probe is specified, can be registered.
(VI) Specification from screen
From the screen, the following need be specified; a test, for which washing of
the sample probe is specified for carry-over evasion, and the detergent set
position on the sample disk. An example of specification is shown below.
[AFP]
↑
Carry-
over
giving test
(CH1 to 36)
(VII) Examples of evading procedure
An example of carry-over evading procedure is shown below.
A to C represent tests, and W stands for washing.
Carry-over Evasion-specified Test
[W1]
↑
Detergent set position
(W1, W2, W3)
..... B
A
Sample i
3 - 9
Example of Evading Procedure
W A B C W
Sample i+1 Sample i+2
A W A B
Sample i+3