![Diatron Abacus + Service Manual Download Page 11](http://html.mh-extra.com/html/diatron/abacus/abacus_service-manual_2494683011.webp)
Abacus
+
Service Manual
rev 1.09
11
The analyzer performs enhanced Hemoglobin measurement technology for HGB
measurement. The output of HGB head is frequency (TSL235 detector is light to frequency
converter). This signal is counted by a digital counter in the FPGA circuit/micro-controller.
This counter counts up while the LED is on and counts down while the LED is off, the LED
and the counter directions are switched with a 100 Hz signal. This method provides “real
time backlight correction”, which makes the HGB measurement more precise in changing
backlight environment situation as well.
There are two kinds of HGB measurements:
Sample measurement
(before RBC counting)
Diluent measurement
(in WBC washing phase)
The HGB result is calculated from these measurements by:
HGB log (CNT
diluent light
/ CNT
sample light
)
In spite of the fact that is less sensitive to incident light changes it is
recommended to keep side door closed during measurements.
2.1.3. Cell counter Amplifier Board
Amplifier board includes its own voltage regulator, the connection interfaces to HGB head, to
high voltage board and to COMB card. In this board there is the current generator circuit,
which works from 50 V measuring voltage (generated by High Voltage Board) and the probe
voltage (DC) is amplified with a voltage follower (output: ELV). Nominal measuring current is
870 µA
.
Amplifier board includes two input connectors for the chambers (measuring electrodes).
There are two reed relays on the input side: IC10 can select between the two channels
(RBC, WBC) with RSW signal; IC11 connects high voltage to the selected probe with HSW
signal. Test circuit makes possible to generate test pulses (with TEST and PLS signals
through FETs) for checking the proper operation of the amplifier channel.
Connection to COMB (AMP and DIGIO)
Connection to the HVB
Reed relays