Siemens SIREMOBIL Iso-C Service Instructions Manual page 125

Supplement, Measuring the tube current
NOTE
•
Switch OFF SIREMOBIL.
•
Remove jumper X97 from board D1.
•
Connect the mA measuring device at D1.X39 and D1.X40.
•
Switch ON SIREMOBIL.
•
Release radiation and read the overall current.
•
Read out the kV value produced while the current is being measured.
Calculate the tube current as follows:
tube current [mA] = overall current [mA] -
e. g:
At 110 kV, an overall current of 5.275 mA is measured.
tube current [mA] = 5.275 [mA] -
Siemens AG
Medical Solutions
When measuring the tube current, the distribution current must
be derived from the measured value. The distribution current
depends upon the kV and is calculated according to Ohm's law.
The distribution resistance is 400 MOhm.
110 [kV]
400 [MOhm]
SPR2-230.061.01
Rev. 13
high voltage [kV]
distribution resistance [MOhm]
= 5.275 [mA] - 0.275 [mA] = 5.0 [mA]
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12.04 CS PS 24
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SIREMOBIL Iso-C
System Manual