Hitachi 902 - Incubator Temperature (Pt Feeler); MPX Data; Temperature Calculation Formula; Temperature Measurement Sequence

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Temperature Measurement Sequence
• Calculation/alarm judgement are made in the past three cycles.
The temperature is judged according to the status and an alarm is output.
The temperature used for judgement is calculated in the following manner.
1. Average of 4 temperature values measured in a single cycle
2. Average temperature in 3 cycles
3. Alarm judgement by value rounded to 1st decimal point and multiplied by 10
(1) MPX Data
No. Item MPX Data
1 Reference voltage (2 V) 6
2 Incubator temeprature 5
3 Reference voltage (6 V) 7
(2) Temperature Calculation Formula
1) Incubator Temperature (Pt feeler)
T = 29.0 × (Y - A)/(B - A) + 7.96
T: Incubator temperature (°C)
Y: ADC count value at measurement
A: Count value for reference voltage (2 V)
B: Count value for reference voltage (6 V)
NOTE: The interrupt register is 100 msec before A/D start.
Dummy lead
Dummy lead Dummy lead
Dummy lead
Dummy lead Dummy lead
Reference
2 V
changeover
Lead/
incubator
changeover
Lead/
incubator
changeover
Lead/
incubator
changeover
Lead/
incubator
changeover
Lead/
incubator
changeover
AD START AD START AD START
AD START
AD START
AD START
Lead
3 cycles (54000)
Cycle 1 Cycle 2
Cycle 3
Temperature ADC : Required time
400 msec × 6 cycles : 2.4 sec