Hoffrichter CARAT I, Service Manual

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to 6.)
The real-time clock is, foremost, to indicate the time for an occurrence of an alarm. Furthermore,
the operator date and time is shown on the display.
to 7.)
The communication with the external peripherals (e.g. Windows computer) is through an isolated
RS232 interface. The programming (software update) of the controller can also be done through
this interface.
to 8.)
The communication with the controller is through another serial interface.
5.1.2 COnTROL SECTIOn
Functions:
1. Control the turbine and the valves, to implement the set respiration modes with the appertain-
ing parameters
2. Detection of alarm situations
3. Communication with the operation controller through a serial interface
4. Communication with the power management controller through a serial interface
to 1.)
The calculation for the nominal values for the motor control is made from the respiratory mode set
and the appertaining parameters. The nominal value output is through a DAC on the motor control.
The nominal values (analog measured values – pressure or flow) are read and evaluated from the
controller.
Furthermore, the switching on/off of the turbine is through the controller, as well as the control of
the (electromagnetic) proportion valve. This valve controls the pneumatic expiration valve in the line
circuit (expiration valve closed

inspiration; expiration valve open

expiration).
to 2.)
The condition of the alarm is checked through the controller, and in the case of an alarm the emis-
sion of an acoustic signal. The volume of this signal is adjustable.
to 3.)
The communication with the operation controller is through a serial interface.
to 4.)
The communication with the power management controller is through a second serial interface.
5.1.3 RS232 CIRCUIT BOARD
The communication with the external peripherals (Windows computer

software CaratControl) is
through the RS232 circuit board. In addition, with the help of this circuit board, a remote alarm box
or a call nurse can be connected to the machine.