B. Braun Vista basic Service Manual page 17

System Overview
Mechanical Occlusion Pressure:
The Vista basic has a linear peristaltic pump. This pump has 12
slides which are driven by a camshaft.
When the pump coveris closed, the pump tube is squeezed (oc-
clusion) by at least one of the slides, independent of the pump
head position. The complete pump unit is mounted behind the
front panel in the cabinet frame. The hinges and the locking bow
for the pump cover are led through the front panel. The pump cov-
er is automatically closed when the operating unit door is closed.
The slides are pressed against the pump cover by a spring system
in the pump unit. Thereby a delivery pressure is realized and
mechanically limited by the springs.
If the pressure limit is exceeded there is no volume delivery.
The drop sensor activates an alarm. If one of the springs fails,
the spring system will ensure that an unsafe condition cannot
occur (free flow). The two remaining springs ensure an ap-
propriately high occlusion pressure.
Electronic Occlusion: Pressure:
The electronic occlusion sensor is mounted on the output side of
the pump. A spring pressure loaded slide is seated on the infusion
line. An increase of pressure in the infusion line leads to a deflec-
tion of the coil core via the pressure slide. The depth of immersion
is measured inductively. When a preset pressure threshold is
reached the pump drive is switched off, and an alarmis activated.
The electronic occlusion pressure is a single channel circuit. In
case of a failure, the mechanically limited maximum pressure can
be reached.
Motor Switch- Off by Both Processors:
Function processor: MS signal to switch-off the motor drive. -
Control processor: MOTEIN signal to switch-off the drive of the
motor operating voltage.
Computer interface
Vista basic 950971 Rev A (5/04)
The Vista basic is equipped with a computer interface. It can be
connected to the optical interface or via the MFC service plug. To
activate the computer operation please ask for a detailed descrip-
tion from B. Braun.