TM 5-6675-323-14
When a pen is installed in a pen stable, it causes the pen stable switch to close,
w h i c h provides a low input signal to PCA A5 via PCA A6. This low signal indicates
that there is a pen in that particular pen stable. Pen-in-arm switch indicates if
there is a pen in the arm via a similar low signal.
3 - 3 . 2 . 5 P e n D r i v e C i r c u i t s . A c c e p t pen position data from PCA A5 and drive the
plotter chart pens along the X- and Y-axes. A s e r i e s o f d r i v e w i r e s a r e u t i l i z e d t o
move the pens, controlled by the pen drive circuits.
The pen drive circuits include the following functional units:
M o t o r driver PCA A8
P e n solenoid
T r a n s i s t o r driver PCA A12
X - and Y-drive motors
3-34
