Rtp Data Bus I/O Latch Cpld Circuitry; Data Acquisition System (Das) Front End Circuitry - Bayer HealthCare RapidPoint 400 Series Service Manual

RTP Data Bus I/O Latch CPLD Circuitry

This section of the Main board contains a group of circuits located in a
CPLD, U38. The majority of the IC takes the data bus signals, D0 to D15
and strobe signals from U37 and other 68332 control signals, such as
DS-, to latch data in and out of U38.
Latch outputs in the logic array block LAB-A direct data to the
micro-stepper microcontroller U39.
Latch inputs in LAB-B direct data to the luer and AQC motor drivers.
Latch outputs in LAB-C and LAB-D direct data to the Multiplexer board
assembly located in the measurement block module.
Latch outputs in LAB-E and LAB-F connect the system data bus (D0 to
D15) to U37, and use the control strobes generated by U37.
Latch outputs in LAB-G and LAB-H receive data from the various system
status sensors and flag signals from the FIFO circuitry.

Data Acquisition System (DAS) Front End Circuitry

This section of the Main board contains the interface to the Multiplexer
board located in the measurement block module. This module receives
parallel data bits from the U38 latches. U38 returns the properly
conditioned sensor analog signal to the 40-pin connector J8. This
connector returns the temperature sensor bridge signals for the preheater
and block heater located in the measurement block module. J8 supplies
+5 V, +12 V, and -12 V to the measurement block module.
The disposable cartridge connected to the measurement block module
contains a small EE memory to retain information about the cartridge
calibration and its history. This EE memory communicates to the Main
board through J8.
There is a 12-bit digital-to-analog converter (DAC) IC U22 contained in this
section of the DAS, and it sends a programmable analog voltage to the
measurement block module to offset each sensor into proper calibration
range. All the analog signals arriving at J8 are in a differential form and
connected to two 16-channel multiplexers, U8 and U9. The MUX0-3
signals generated from latches on U38 control U8 and U9. The selected
differential pair of signals is then sent to the next section.
Rev. C Electronic System Overview 85