B. Braun Infusomat fmS, Service Manual

Page: 15 / 86

System Overview
1
Infusomat® fmS 2.3 gb 1 - 5
Voltage Supply The voltage supply is generated either directly from mains, via the
FM connector (14 V connection to the fluid manager system), or
via the MFC-connector (11 to 16 V) and as an internal supply via
the internal 7.2 V NiCD battery. The mains module is available in
three versions: 230 V, 220 / 230 / 240 V and 100 / 110 / 120 V.
The rated voltage has a tolerance of + 10% to – 15 %.
A voltage of 11 V to 18 V is available after transformation and
rectification. This voltage is fed to the battery charge circuit and
the unit supply. This is also valid for an external 12 V supply from
the MFC- or FM-connector. The FET V10 switches between the ex-
ternal and the internal voltage supply. The transistor V10b works
as an ON/OFF switch for the operating voltages UPS, UMOT and
+5V. The +5V supplies the complete electronics including the
double channel microprocessor system. A window comparator
constantly monitors the +5V for undervoltage or overvoltage. The
function is checked during switch-on. The operating voltage UPS
supplies the stepper motor and the UMOT, the stepper motor
drive.
The transistor V47 switches the operating voltage UMOT. In case
of an alarm the motor is switched off by V47. Additionally the
switching function of the transistor is checked during the switch-
on test.
The circuit has two separate assembly groups with separate sup-
ply voltages UBA and UBB. The ON/OFF circuit has a retriggerable
delay switch-off. A follow-up charging circuit drives the transis-
tor V10b.
The alarm logic (operating voltage UBB) is an RS latch. This is set
when the unit is running and activates the alarm circuit. The
alarm buzzer and driver are also driven by UBB. The ON/OFF circuit
is activated and the voltage supply is switched on by pressing the
ON/OFF key. The alarm latch is reset simultaneously. A function
test of the voltage monitoring, motor circuit and alarm activation
is performed. The voltage supply is maintained by cyclic self-hold-
ing pulses fed to the logic. The alarm latch is also activated.