Siemens MOBILETT Plus Manual page 47

Integration of the tube current
The block diagrams and the wiring diagram X037E, sheet 140 are the basis for the func-
tional description given below.
The actual tube current is led via a measuring resistor in the single tank and cable K9 to
the CPU board D1.
Fig. 1
There it can be measured at test point "MA POS".
Before the exposure release the selected mAs value is stored as binary information in a
software-implemented counter.
Beginning 0.7 ms after the start of exposure the actual tube current "MA POS" is mea-
sured every 50 µs by the microprocessor 80C166 on the CPU board D1 until the exposure
is completed.
The result of the measurement is used to decrease the counter.
Fig. 2
Siemens-Elema AB
Solna, Sweden
Simultaneously, each measured actual tube current value is compared with a
minimum value of 5 mA.
Register 6
"MA POS" curve for a long-time exposure
SPR8-215.850.02
Rev. 01 01.02
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