Fluke Biomedical TNT 12000 - Manual (Page 71)

Operation
How to Use the mAs Detector (TNT 12000 mAs)
2
2-43
Clamp Connections
Some dental X-ray heads do not have an access to the tube current. Some X-ray circuits
are contained inside the X-ray head. Other systems measure current as a voltage across an
internal resistor. The mAs shunt can not be used on these X-ray systems. For these cases,
use a non-invasive current clamp. To make an mA or mAs measurement:
1. Put the clamp around the anode cable where it exits the X-ray tube. Make sure the
jaws are completely closed around the cable. For correct polarity, make sure the
arrow on the moveable jaw of the clamp points in the direction of current flow in the
cable.
2. Connect the clamp to the mAs input connector with the BNC female to banana plug
and the mA/mAs interface cable.
3. Turn on the clamp and set to the 4A range.
4. Zero the clamp before the measurement.
5. Make an exposure.
6. Read the current in the Display.
How to Measure mAs
After the mAs measurement options are set, the MEASUREMENT screen in Figure 2-20
shows in the display.
fct19.bmp
Figure 2-20. mAs Measurement Screen
After the mAs is connected to the X-ray tube, the MEASUREMENT screen is refreshed
with the new measurements after each exposure.