P.c.b. Lp 941 Hydraulics Processor - Fresenius Medical Care 4008 E Technical Manual

8.33

P.C.B. LP 941 Hydraulics processor

8.33.1 Description
Voltage supply
The PC board is supplied with 24 V via plug X1. The switching regulator IC 10 which generates
+5 V max., 1 A from 24 V is used for operation of the processor system. The IC 18 serves to
supply the operation amplifier with +12 V. The reference voltage is generated with the reference
voltage source IC 15 as well as IC 5. T8 is a power driver for the bridge voltage of the pressure
transducers. IC 23 and T 7 are used to generate the negative supply voltage for the instrument
amplifier. For delayed switching on of the operating voltages, the two switch controllers IC 10 and
IC 18 are enabled with the low level on pin 5 only when the applied +24 V has become stable for
approx. 5 seconds (watchdog test of 4008). Evaluation is performed with the comparator circuit
associated with IC 13a.
Processor system
Technical data:
– SAF C515C processor
– 6 MHz clock frequency
– 64 KByte EPROM
– 32 KByte RAM
– 16 KBit serial EEPROM
– 10 Bit A/D converter with 8 multiplexed inputs
– 6 ports
– CAN controller AN 82527
– Interface for CAN driver
– 2 ports
The SAF C515C IC 8 receives its 6 Mhz clock frequency via GAL IC 7, pin 19. The oscillator
frequency of 12 Mhz is generated by a separate oscillator component Q1 and divided by 2 for
operation of the controller in the GAL.
The 12 Mhz clock from the oscillator component is directly applied to CAN controller IC 9, pin 18.
The SAF C515C operates with a multiplexed data/address bus. The upper addresses A8 to A15
are available at port 2 and the lower addresses A0 to A7 are available at address latch IC 3 after
decoding.
The IC 22 is a 64k x 8 Eprom.
The RAM, IC 6, has a memory area of 32k x 8.
The GAL IC 7 is used for the decoding of the chip select signals. The EEPROM IC 11 is provided
for the backup of calibration data and treatment data during a power failure.
The integrated CAN controller of SAF C 515 C is used for communication with the CPU 1. Data
exchange is performed via pins 79/80 of IC 8 and via the CAN bus driver IC 12.
The additional CAN controller IC 9 with the CAN bus driver IC 25 is provided for future options in
the hydraulics system which will be performed with intelligent actuators.
Data exchange with the additional CAN controller is performed via the data bus in conjunction
with the signals /CS_CAN und /INT_CAN for transmitting and receiving as well as /RD and/WR
for reading and writing the ports of IC 9.
Fresenius Medical Care 4008 4/09.03 (TM)
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