uniphy Phyaction V, Руководство по обслуживанию

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Service manual Phyaction V
Service manual version 0.1 Page 6
5. Circuit description
5.1 Power supply
The device is mains powered. It sports an all-range off-line switched mode power supply ,
meaning it can be used all over the world without having to select a working voltage or
frequency. But of course the the plug of the power cord has to fit into the local outlet type.
5.2 Patient Current Routing
The electrotherapy outputs of the main unit are connected to the vacuum unit, at the rear, and
the electrodes are connected to the front of the vauum unit. As long as the vacuum is not used
the traditional electrodes function as before, even when the vacuum unit is not switched on.
As soon as the vacuum is turned on the patient current is switched from the traditional
electrodes to the connectors for the hoses at the other end of which the suction cups are. In the
hoses is a wire that feeds the patient current to a metal plate inside the cup. Contact with the
the skin of the patient is established by a moisturized sponge. The switchover always happens
for channel A but the operator can add channel B by pressing a button that toggles the choice
between traditional and vacuum electrodes.
5.3 Vacuum
When the vacuum control is turned up, air is pumped out to create the vacuum until the set
level is reached. The hose connectors limit the air flow into each hose so one can put the
vacuum electrodes one at a time in their place. When channel B is not used, its connectors
should be plugged by connecting them to each other by a hose, otherwise the pump keeps
running and deeper vacuum levels cannot be reached.
5.3.1 Control Loop
A pressure sensor measures the vacuum level and a control loop powers the pump if the set
level is deeper or opens a valve to let air in when lower . In continuous mode this results in only
the pump being run very lightly, making up up for the small air leakage between the cups and
the skin and at the connectors.
5.3.2 Pulsed Vacuum
When the electrodes are in place the operator can pulsate the vacuum to mitigate the effect
vacuum has on patients with a vulnerable skin. When pulsating, the vacuum is raised by 50%
during 1.5 second and then returns for 1.5 to 4.5 seconds to the level set for continuous
operation. As a result the pump will run during the 1.5 second period of deepened vacuum after
which the valve will be opened until the base level is reached again.