Illinois Tool Works IJ300, Operation Manual

Page: 90 / 125

Controller
Appendix B: Theory of Operation
Page 80 of 115 5760-121 Operations Manual Rev B
Integrated Valve Print Head Interface Board
The IV Print Head Interface Board controls the print head daisy chain, and it is the power
entry point for the print heads and the rest of the system (See the
Power section above.)
The Print Head Interface Board also contains the photosensor and external encoder con-
nectors.
The daisy chain controller is made up of an FPGA (U3) and print image RAM (U5). The
print image is written to image RAM by the CPU board, and circuitry on the FPGA reads
the print image and shifts it out to the print heads. The generation and timing of all daisy
chain signals - DATA, CLOCK and LATCH - take place in the FPGA in response to signals
from the photosensor and encoder.
Test Points: TP1: 5VDC
TP2: 3.3VDC
TP3: (FPGA) DONE. LOW when the FPGA is being programmed. High
when FPGA programming is complete.
TP4: Print head CLOCK signal
TP5: Print head DATA signal
TP6: Print head LATCH signal
TP8: PHOTOSENSOR signal
TP9: DC power in (15V)
TP10: External ENCODER signal
TP11: GND
TP12: (FPGA) INIT; goes LOW to indicate an FPGA programming error.
TP13: (FPGA) PROGRAM; pulses low to initiate FPGA programming.
TP4
TP3
TP5 TP6
J2
TP8
TP9
TP10
J1
TP11
TP12
TP13
TP1
TP2
P2 J4
IV INTERFACE
BOARD
U5
U3