Fresenius Medical Care 4008 4/09.03 (TM) 8-65
8.12 P.C.B. LP 632 CPU 2
8.12.1 Description
● Technical data
– 80C535 processor
– 11-MHz clock pulse frequency
– 128 Kbyte EPROM
– 8 Kbyte NOVRAM + 2 Kbyte SRAM
– Serial interface
(Baud rate 9600, 8 data bits, 1 stop bit, no parity bit)
– 9 analog inputs (0 to 10 V)
– 40 digital inputs (24 V, 12 V, TTL level)
– 6 analog outputs (0 to 10 V)
– 24 digital outputs (TTL level, Darlington output stages)
● General information
P.C.B. LP 632 (CPU 2) has the following functions in the hemodialysis machine:
– T1 test generation
– Monitoring functions:
a) Transmembrane pressure
b) Conductivity
c) Temperature
d) Hardware and software watchdog
e) UF pump monitoring
– Calibration voltages for:
a) Dialysate pressure (TMP display)
b) Temperature display
P.C.B. LP 632 (CPU 2) constitutes a closed self-contained processor system (stand-alone
system). Basically, the electronics of the CPU 2 comprises three essential functional blocks:
– Analog and digital inputs
– Microcontroller system
– Analog and digital outputs