Siemens MOBILETT Plus Manual page 33

Collimator-lamp control
The block diagrams and the wiring diagram X037E, sheet 180 are the basis for the
functional description given below.
The control circuit for the halogen collimator lamp in the multileaf collimator includes the
Control and display panel, the boards D3, D1, D8 and D4 and the multileaf collimator,
Z66.
•
one switch is located directly on the multileaf collimator,
•
the other switch is on the Control and display panel.
The two control signals from these switches are handled and processed independently by
the microprocessor on the CPU board D1.
When one of the switches is pressed, the microprocessor on the CPU board D1 gener-
ates the control signal "LAMP ON" for the control relay "LR1" on board D4. It is possible to
measure this control signal on board D4 at the test point "LAMP ON".
When control relay "LR1" makes contact, an AC voltage of about 22 V is supplied to the
collimator lamp. This is the same 22 V signal used following rectification to switch on the
turn plate.
In case the collimator lamp is switched on during the charging of the capacitor bank, M1,
before the signal "CHARGE HIGH" is finished, the charging procedure is interrupted for
about 1 s and then resumed again - as long as the filament of the lamp is still "cool".
Either of the two control switches can be used to switch off the collimator lamp.
If the collimator lamp is not switched off in this way, after 30 s the microprocessor on the
CPU board D1 will switch it off. The lamp is also automatically switched off after an expo-
sure.
Siemens-Elema AB
Solna, Sweden
The collimator lamp is controlled by two switches.
Register 6 SPR8-215.850.02
Rev. 01 01.02
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