CPI CMP 200 Series Service Manual page 286

CPI Canada Inc.
7.2.4 X-ray exposure (Cont)
Pressing X-RAY on the membrane console will energize U10 on the console board. If U10 is energized,
or one of the X-RAY switches on the touchscreen console, X-ray mini-console, or on the associated hand
switches is pressed, U9 and U7 on the generator control board will be energized. The output of U10 on
the console board is read by the console CPU, and the output of U7 on the generator control board is
read by the generator CPU via data buffer U71. An X-ray request will be recognized if the output of U10
on the console board (membrane console only) and / or U7 on the generator control board is low. When
the generator CPU receives an X-ray request, the emitter of U9 on the generator control board will be
pulled low via U86 and driver U83, assuming that there are no errors that would prevent an exposure.
With U9 on the generator control board energized, and its emitter held low, the collector of U9 will be held
low.
Jumpers JW1 and JW2 on the console board (membrane consoles) may be removed to disable the
console PREP and X-RAY buttons. If these jumpers are removed, PREP and X-RAY requests may be
made via a hand switch connected to J3 on the membrane console.
Refer to MD-0931, sheet 2:
The collector of opto-coupler U9 on the generator control board (page 1) is OR'ed with several other
signals on the generator control board, all of which must be at the correct logic level in order to be able to
make an X-ray exposure.
•
The base of Q27 on the generator control board must be held low to allow an exposure. This requires
the following conditions:
∗
The output of U65 must be low, indicating that no fault has been detected by the CPU.
∗
The X-RAY ENABLE command from U9 (page 1) or U11 (MD-0926) must be low.
∗
The HT tank must be connected, holding the line connected to TP17 low.
•
The base of Q26 must be held low by U67, indicating a valid X-ray request.
With the base of Q26 and Q27 held low, Q26 and Q27 will be off. The line connected to TP16 on the
generator CPU board will then be pulled high via R91, pulling the control inputs on AND gates U26A and
U26B on the generator control board high, as described in 7.2.5.
Lastly, with the output of U67 on the generator control board low, the collector of Q21 will be high. This
turns Q22 off, isolating Q22 from the kV demand circuit, part of 7.2.5.
Use and disclosure is subject to the restrictions on the title page of this CPI document.
®
CMP 200 X-Ray Generator Service Manual Ch # 901476-09 Rev. C
7
Theory of Operation
Page 7-5