Medivance Arctic Sun 2000, Руководство по обслуживанию

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is referenced to chassis ground. The other islands are isolated from the Backplane island by
opto-isolators or transformers. The RS-232 #1, RS-232 #2, and Temperature Out (Echo) islands
are isolated from the Backplane and from each other to a breakdown voltage of at least 500V.
The patient temperature island is isolated from all others to a level of 1500V. It should be noted
that, in addition to this, the 24V power supply in the Power Module isolates all low voltage
circuitry to a level of 4000V from Mains.
ƒ Input/Output (I/O) Circuit Card: The I/O Card contains the majority of the actuator and sensor
circuitry. T1, T2, T3, and T4, the flowmeter, pressure sensor, and level sensor are conditioned on
the I/O Card. Both pump motors, the valves, and the refrigeration system are controlled by this
circuit card.
The remaining circuitry is housed in the Remote Display Module. This module communicates with
the card cage via a cable having 13 twisted pairs using a technology called Low Voltage Differential
Signaling (LVDS) which minimizes both the risk of spurious signals interfering with communication
and the emission of electromagnetic energy. The Remote Display Module houses LED display
drivers, keyboard interpretation circuitry, an audible alarm (primary), and an LCD text module.
There is also a manually resettable thermal breaker mounted on the heater casing. This breaker is
not used for normal temperature control, only to ensure that in the event of control failures the heater
does not over heat.