HP 220 - Manual (Page 61)

5Ć29 Functional Overview C3187Ć90000
Carriage PCA
The carriage PCA has four main functions:
D The nozzleĆtiming ASIC controls the firing of the print cartridges, using data from the
shuffler ASIC on the main PCA.
D A linear encoder senses the carriage position.
D A line sensor enables automatic printĆcartridge calibration.
D A thermistor monitors the temperature near the print cartridges.
The carriage PCA is installed in the carriage assembly, componentĆside down to accommodate
the operation of the linear encoder. A long 28Ćconductor cable (trailing cable) connects the
carriage PCA to the main PCA.
Voltage and Energy The carriage PCA requires 5 V @ 670 mA and 20 V @ 61 to 218 mA.
The regulator for the 20ĆV supply is located on the main PCA, but an active sense circuit on
the carriage PCA senses the voltage at the highĆfrequency bulk charge source capacitors.
Carriage Processor System
The carriage processor system consists of the following:
D Carriage processor
D Nozzle timing ASIC
D Servo processor interface
D AnalogĆtoĆDigital (A/D) Converter
D Print cartridges
D Line sensor
Carriage Processor
The carriage processor's primary task is to configure the nozzleĆtiming ASIC. It receives the
configuration data from the servo processor. It controls the A/D converter used in the line
and temperature sensors, and senses printĆcartridge identity and continuity. It returns
status and sensor data to the servo processor.
To Servo
Processor
System
From Main
Processor
System
8052
Carriage
Processor
Thermistor
Line Sensor
Cartridge
Cartridge
Drivers Nozzle
Timing ASIC
A/D Converter
Carriage-Processor-System